Minor optimizations

– allow local constants in macros
– allow untyped macro parameters with void
– treat the name of a function as a pointer to it
– add this.function local alias (#118)

.gitignore

@@ -31,9 +31,12 @@ issue*.mfk
 *.seq
 *.asm
 *.lbl
+*.labels
 *.nl
 *.fns
 *.sym
+*.mlb
+*.dbg
 *.deb
 *.xex
 *.nes

CHANGELOG.md

@@ -1,5 +1,69 @@
 # Change log
 
+## 0.3.30 (2021-12-15)
+
+* Added volatile structure fields (#112).
+
+* Added `this.function` as the alias for the current function (#118).
+
+* Added support for constant evaluation in `file` expressions (#114).
+
+* Allowed declaring local constants and passing untyped parameters for macros.
+
+* Allowed treating bare function name as a pointer to it.
+
+* Added Mesen, ld65 and "raw" label file formats (#128).
+
+* Commodore: the address used by SYS is now determined automatically instead of hardcoded (#111).
+
+* C64: Fixed address for `sid_v1_sr` (#115).
+
+* EasyFlash: Fixed address for `switch_hirom` (#121).
+
+* GB: Fixed standard library (thanks to @retrac0).
+  
+* Commander X16: Updated platform definition file (thanks to @mookiexl).
+
+* 65CE02: Full assembly support.
+
+* R800: Full assembly support.
+
+* Various miscompilation fixes (#123, #125) and parser fixes (e.g. #120).
+
+* 6809: Various optimizations.
+
+* Improvements related to constant evaluation.
+
+## 0.3.28 (2021-05-24)
+
+* Officially deprecated decimal operators with apostrophes.
+
+* Added optimization hints.
+
+* Added `utf32be`, `utf32le`, `cp1253`, `cp1254`, `cp1257`, `geos_de` encodings.
+
+* Allowed for underscores in numeric literals for readability purposes, similar to several other programming languages. 
+
+* Added a warning for comparisons between bytes and pointers (#110).
+
+* Fixed escape sequences in many encodings.
+
+* Fixed and documented absolute module imports (#106)
+  
+* Fixed and optimized sign extension.
+  
+* Fixed optimizations involving unused labels.
+  
+* Fixed pointer types to type aliases.
+
+* Fixed parsing of Intel hex literals of the form `0BH`, `0B0H` etc. 
+
+* 6809: Fixed flow analysis in optimization.
+
+* Optimization of certain bitmask operations.
+
+* Parsing optimizations.
+
 ## 0.3.26 (2021-03-01)
 
 * Array fields in structs.

README.md

@@ -5,7 +5,7 @@
 A middle-level programming language targeting 6502-based, 8080-based, Z80-based and 6809-based microcomputers. 
 
 For binary releases, see: [https://github.com/KarolS/millfork/releases](https://github.com/KarolS/millfork/releases)
-(latest: 0.3.24).  
+(latest: 0.3.30).  
 For build instructions, see [Build instructions](./COMPILING.md).
 
 ## Features

build.sbt

@@ -1,6 +1,6 @@
 name := "millfork"
 
-version := "0.3.26"
+version := "0.3.31-SNAPSHOT"
 
 // keep it at 2.12.11 for GraalVM native image compatibility!
 scalaVersion := "2.12.11"

docs/abi/inlining.md

@@ -14,6 +14,8 @@ It implies the following:
 
 * cannot contain variable or array declarations
 
+  * but can contain scalar constant declarations; the constants are scoped to the particular macro invocation
+
 * can be `asm` - in this case, they should **not** end with a return instruction
 
 * do not have an address
@@ -35,7 +37,13 @@ It implies the following:
     * `call` parameters exceptionally can have their type declared as `void`;
     such parameters accept expressions of any type, including `void`, however, you cannot assign from those expressions
 
-* macros do not have their own scope (they reuse the scope from their invocations) – exceptions: the parameters and the local labels defined in assembly
+* macros do not have their own scope (they reuse the scope from their invocations) – exceptions: 
+ 
+  * the parameters
+
+  * the local labels defined in assembly
+
+  * the local constants
 
 * control-flow statements (`break`, `continue`, `return`, `goto`, `label`) are run as if places in the caller function
 

docs/api/command-line.md

@@ -47,6 +47,12 @@ The extension and the file format are platform-dependent.
     * `-G sym` – format used by the WLA DX assembler. The extension is `.sym`.
     
     * `-G fceux` – multi-file format used by the FCEUX emulator. The extension is `.nl`.
+    
+    * `-G mesen` – format used by the Mesen emulator. The extension is `.mlb`.
+    
+    * `-G ld65` – a simplified version of the format used by the `ld65` linker (used by CC65 and CA65). The extension is `.dbg`.
+    
+    * `-G raw` – Millfork-specific format. The extension is '.labels'. Each row contains bank number, start address, end address (if known), object type, and Millfork-specific object identifier. 
 
 * `-fbreakpoints`, `-fno-breakpoints` – 
 Whether the compiler should use the `breakpoint` macro.
@@ -206,6 +212,10 @@ The compiler doesn't support accessing the stack variables via the S stack point
 
 * `-O9` – Optimize code using superoptimizer (experimental). Computationally very expensive, decent results.
 
+* `-fhints`, `-fno-hints` – 
+Whether optimization hints should be used.
+Default: yes.
+
 * `-finline`, `-fno-inline` – Whether should inline functions automatically.
 See the [documentation about inlining](../abi/inlining.md). Computationally easy, can give decent gains.
 `.ini` equivalent: `inline`.
@@ -289,6 +299,10 @@ You can also enable or disable warnings individually:
     Whether should warn about deprecated aliases.
     Default: enabled.
 
+* `-Wcomparisons`, `-Wno-comparisons` –
+    Whether should warn about comparisons between bytes and pointers.
+    Default: enabled.
+
 * `-Wextra-comparisons`, `-Wno-extra-comparisons` –
     Whether should warn about simplifiable unsigned integer comparisons.
     Default: disabled.
@@ -312,3 +326,7 @@ You can also enable or disable warnings individually:
 * `-Wuseless`, `-Wno-useless` –
     Whether should warn about code that does nothing. 
     Default: enabled.
+
+* `-Whints`, `-Wno-hints` –
+    Whether should warn about unsupported optimization hints.
+    Default: enabled.

docs/api/commodore-programming-guide.md

@@ -2,6 +2,11 @@
 
 ### A note about Commodore 64
 
+#### Unusual main function location
+
+If you're creating a prg file and your `main` function may be located at address $2710 hex (10000 decimal) or higher,
+you might need to define the `DISPLACED_MAIN=1` preprocessor feature. 
+
 #### Multifile programs
 
 A multifile program is a program stored on a disk that consists of the main program file that is executed first

docs/api/custom-platform.md

@@ -37,6 +37,8 @@ if a line ends with a backslash character, the value continues to the next line.
     * `z80` (Zilog Z80)
     
     * `strictz80` (Z80 without illegal instructions)
+
+    * `r800` (R800)
     
     * `z80next` (Z80 core from ZX Spectrum Next)  
     Note: Millfork version 0.3.18 and earlier uses the name `zx80next` for this architecture.
@@ -80,6 +82,8 @@ This list cannot contain module template instantiations.
     * `emit_x80` – whether the compiler should emit instructions present on Sharp LR35902 and Z80, but absent on Intel 8080, default is `true` on compatible processors and `false` elsewhere
 
     * `emit_z80` – whether the compiler should emit Zilog Z80 instructions not covered by `emit_x80`, default is `true` on compatible processors and `false` elsewhere
+
+    * `emit_r800` – whether the compiler should emit R800 instructions, default is `true` on compatible processors and `false` elsewhere
     
     * `prevent_jmp_indirect_bug` – whether the compiler should try to avoid the indirect JMP bug, 
     default is `false` on 65C02-compatible or non-6502 processors and `true` elsewhere
@@ -263,3 +267,7 @@ Default: `main,*`
     * `sym` – format used by the WLA/DX assembler. The extension is `.sym`.
     
     * `fceux` – multi-file format used by the FCEUX emulator. The extension is `.nl`.
+    
+    * `mesen` – format used by the Mesen emulator. The extension is `.mlb`.
+    
+    * `ld65` – format used by the `ld65` linker. The extension is `.dbg`.

docs/doc_index.md

@@ -44,6 +44,8 @@
 
 * [Important guidelines regarding reentrancy](lang/reentrancy.md)
 
+* [Optimization hints](lang/hints.md)
+
 * [List of keywords](lang/keywords.md)
 
 ## Library reference

docs/lang/custom-encoding.md

@@ -16,7 +16,7 @@ No other lines are allowed in the file.
 * `NAME=<name>` defines the name for this encoding. Required.
 
 * `BUILTIN=<internal name>` defines this encoding to be a UTF-based encoding.
-`<internal name>` may be one of `UTF-8`, `UTF-16LE`, `UTF-16BE`.
+`<internal name>` may be one of `UTF-8`, `UTF-16LE`, `UTF-16BE`, `UTF-32LE`, `UTF-32BE`.
 If this directive is present, the only other allowed directive in the file is the `NAME` directive.
 
 * `EOT=<xx>` where `<xx>` are two hex digits, defines the string terminator byte.

docs/lang/functions.md

@@ -4,17 +4,17 @@
 
 Syntax:
 
-`[segment (<segment>)] [<modifiers>] <return_type> <name> ( <params> ) [align ( <alignment> )] [@ <address>] { <body> }`
+`[segment (<segment>)] [<modifiers>] <return_type> <name> ( <params> ) [align ( <alignment> )] [<optimization hints>] [@ <address>] { <body> }`
 
-`[segment (<segment>)] [<modifiers>] <return_type> <name> ( <params> ) [align ( <alignment> )] [@ <address>] = <expression>`
+`[segment (<segment>)] [<modifiers>] <return_type> <name> ( <params> ) [align ( <alignment> )] [<optimization hints>] [@ <address>] = <expression>`
 
-`[segment (<segment>)] asm <return_type> <name> ( <params> ) @ <address> extern`
+`[segment (<segment>)] asm <return_type> <name> ( <params> ) [<optimization hints>] @ <address> extern`
 
 Examples:
 
     void do_nothing() { }
     inline byte two() = 2
-    asm void chkout(byte register(a) char) @ $FFD2 extern
+    asm void chkout(byte register(a) char) !preserves_x !preserves_y @ $FFD2 extern
     segment(prgrom0) void main_loop(word w, byte x) align(fast) { // body omitted
     
 
@@ -68,6 +68,8 @@ For assembly functions, certain parameter names are interpreted as CPU registers
     * on 6502, it means that the function will not cross a page boundary if possible
     * on Z80, it is ignored   
 
+* `<optimization hints>` is a list of [optimization hints](./hints.md), separated by spaces
+
 * `<address>` is a constant expression that defines where in the memory the function is or will be located.
 
 * `extern` is a keyword than marks functions that are not defined in the current program, 

docs/lang/hints.md

@@ -0,0 +1,84 @@
+[< back to index](../doc_index.md)
+
+# Optimization hints
+
+Optimization hints are optional annotations for functions and variables
+that allow the compiler to make extra assumptions that help with code optimization.
+
+The general idea is that removing or disabling optimization hints will not break the code,
+but adding invalid optimization hints may break the code.
+
+Every optimization hint's name starts with an exclamation mark.
+
+Optimization hints marked with **(X)** currently do nothing and are planned to be implemented in the future. 
+
+## Hints for functions
+
+* `!preserves_memory` – the function does not write to memory
+
+* `!idempotent` – calling the function multiple times in succession has no effect
+
+* `!hot` – the function is hot and should be optimized for speed at the cost of increased size
+
+* `!cold` **(X)** – the function is cold and should be optimized for size at the cost of increased run time
+
+* `!odd` – the function returns an odd value
+  
+* `!even` – the function returns an even value
+
+## Hints for 6502 assembly functions
+
+These hints have only effect when used on an assembly function on a 6502 target:
+  
+* `!preserves_a` – the function preserves the contents of the A register
+
+* `!preserves_x` – the function preserves the contents of the X register
+
+* `!preserves_y` – the function preserves the contents of the Y register
+
+* `!preserves_c` – the function preserves the contents of the carry flag
+
+## Hints for 8080/Z80/LR35902 assembly functions
+
+These hints have only effect when used on an assembly function on a 8080-like target:
+  
+* `!preserves_a` – the function preserves the contents of the A register
+
+* `!preserves_bc` – the function preserves the contents of the B and C registers
+
+* `!preserves_de` – the function preserves the contents of the D and E registers
+
+* `!preserves_hl` – the function preserves the contents of the H and L registers
+
+* `!preserves_cf` – the function preserves the contents of the carry flag
+
+## Hints for 6809 assembly functions
+
+These hints have only effect when used on an assembly function on a 6809 target:
+  
+* `!preserves_a` – the function preserves the contents of the A register
+
+* `!preserves_b` – the function preserves the contents of the B register
+
+* `!preserves_d` – the function preserves the contents of the A and B register
+
+* `!preserves_dp` **(X)** – the function preserves the contents of the DP register; exceptionally this can also be used on non-assembly functions
+
+* `!preserves_x` – the function preserves the contents of the X register
+
+* `!preserves_y` – the function preserves the contents of the Y register
+
+* `!preserves_u` – the function preserves the contents of the U register
+
+* `!preserves_c` – the function preserves the contents of the carry flag
+
+## Hints for variables
+  
+* `!odd` **(X)** – the variable can only contain odd values
+
+* `!even` **(X)** – the variable can only contain even values
+
+
+
+
+

docs/lang/literals.md

@@ -14,7 +14,14 @@ Octal: `0o172`
 
 Hexadecimal: `$D323`, `0x2a2`
 
-When using Intel syntax for inline assembly, another hexadecimal syntax is available: `0D323H`, `2a2h`.
+Digits can be separated by underscores for readability. Underscores are also allowed between the radix prefix and the digits:
+
+    123_456
+    0x01_ff
+    0b_0101_1111__1100_0001
+    $___________FF
+
+When using Intel syntax for inline assembly, another hexadecimal syntax is available: `0D323H`, `2a2h`, `3e_h`.
 It is not allowed in any other places.
 
 The type of a literal is the smallest type of undefined signedness
@@ -65,7 +72,7 @@ and the byte constant `nullchar_scr` is defined to be equal to the string termin
 You can override the values for `nullchar` and `nullchar_scr`
 by defining preprocessor features `NULLCHAR` and `NULLCHAR_SCR` respectively. 
 
-Warning: If you define UTF-16 to be you default or screen encoding, you will encounter several problems:
+Warning: If you define UTF-16 or UTF-32 to be you default or screen encoding, you will encounter several problems:
 
 * `nullchar` and `nullchar_scr` will still be bytes, equal to zero.
 * the `string` module in the Millfork standard library will not work correctly
@@ -75,21 +82,26 @@ Warning: If you define UTF-16 to be you default or screen encoding, you will enc
 You can also prepend `p` to the name of the encoding to make the string length-prefixed.
 
 The length is measured in bytes and doesn't include the zero terminator, if present.
-In all encodings except for UTF-16 the prefix takes one byte,
+In all encodings except for UTF-16 and UTF-32 the prefix takes one byte,
 which means that length-prefixed strings cannot be longer than 255 bytes.
  
 In case of UTF-16, the length prefix contains the number of code units,
 so the number of bytes divided by two,
 which allows for strings of practically unlimited length.
-The length is stores as two bytes and is always little endian,
+The length is stored as two bytes and is always little endian,
 even in case of the `utf16be` encoding or a big-endian processor.
+ 
+In case of UTF-32, the length prefix contains the number of Unicode codepoints,
+so the number of bytes divided by four.
+The length is stored as four bytes and is always little endian,
+even in case of the `utf32be` encoding or a big-endian processor.
 
         "this is a Pascal string" pascii
         "this is also a Pascal string"p
         "this is a zero-terminated Pascal string"pz
 
 Note: A string that's both length-prefixed and zero-terminated does not count as a normal zero-terminated string!
-To pass it to a function that expects a zero-terminated string, add 1 (or, in case of UTF-16, 2):
+To pass it to a function that expects a zero-terminated string, add 1 (or, in case of UTF-16, 2, or UTF-32, 4):
 
     pointer p
     p = "test"pz

docs/lang/modules.md

@@ -11,7 +11,8 @@ Each module has a name, which is its unique identifier.
 A module name is a sequence of slash-separated valid Millfork identifiers.
 The name also defines where the module is located:
 a module named `a/b` is presumed to exist in `a/b.mfk`
-and it's looked up first in the current working directory,
+and it's looked up first in the directory that contains the current source file,
+then in the current working directory,
 and then in the include directories.
 
 A module can import other modules, using the `import` statement. 

docs/lang/operators.md

@@ -18,9 +18,9 @@ Millfork has different operator precedence compared to most other languages. Fro
 
 * `->` and `[]`
 
-* `*`, `*'`, `/`, `%%`
+* `*`, `$*`, `/`, `%%`
 
-* `+`, `+'`, `-`, `-'`, `|`, `&`, `^`, `>>`, `>>'`, `<<`, `<<'`, `>>>>`
+* `+`, `$+`, `-`, `$-`, `|`, `&`, `^`, `>>`, `$>>`, `<<`, `$<<`, `>>>>`
 
 * `:`
 
@@ -34,16 +34,16 @@ Millfork has different operator precedence compared to most other languages. Fro
 
 You cannot use two different operators at the same precedence levels without using parentheses to disambiguate. 
 It is to prevent confusion about whether `a + b & c << d` means `(a + b) & (c << d)` `((a + b) & c) << d` or something else.   
-The only exceptions are `+` and `-`, and `+'` and `-'`. 
+The only exceptions are `+` and `-`, and `$+` and `$-`. 
-They are interpreted as expected: `5 - 3 + 2 == 4` and `5 -' 3 +' 2 == 4`.  
+They are interpreted as expected: `5 - 3 + 2 == 4` and `5 $- 3 $+ 2 == 4`.  
-Note that you cannot mix `+'` and `-'` with `+` and `-`. 
+Note that you cannot mix `$+` and `$-` with `+` and `-`. 
 
-Certain operators (`/`, `%%`, `<<`, `>>`, `<<'`, `>>'`, `>>>>`, `:`, `!=`) cannot have more than 2 parameters,
+Certain operators (`/`, `%%`, `<<`, `>>`, `$<<`, `$>>`, `>>>>`, `:`, `!=`) cannot have more than 2 parameters,
 i.e. `x / y / z` will not compile.
 
 The decimal operators have two different forms:
 
-* apostrophe form (e.g. `+'`) – the original one, to be deprecated in the future, may be removed in Millfork 0.4
+* apostrophe form (e.g. `+'`) – the original one, deprecated, will be removed in Millfork 0.4
 
 * dollar form (e.g. `$+`) – available since Millfork 0.3.22
 
@@ -135,20 +135,20 @@ These operators work using the decimal arithmetic (packed BCD).
 
 On Ricoh-based targets (e.g. Famicom) they require the zeropage register to have size at least 4
 
-* `+'`, `-'`: decimal addition/subtraction  
+* `$+`, `$-`: decimal addition/subtraction  
-`$+`, `$-`: (since Millfork 0.3.22)  
+`+'`, `-'`: (deprecated form)  
-`byte +' byte`  
+`byte $+ byte`  
-`constant word +' constant word`  
+`constant word $+ constant word`  
-`constant long +' constant long`  
+`constant long $+ constant long`  
-`word +' word` (zpreg)
+`word $+ word` (zpreg)
 
-* `*'`: decimal multiplication  
+* `$*`: decimal multiplication  
-`$*`: (since Millfork 0.3.22)  
+`*'`: (deprecated form)  
-`constant *' constant`
+`constant $* constant`
 
-* `<<'`, `>>'`: decimal multiplication/division by power of two  
+* `$<<`, `$>>`: decimal multiplication/division by power of two  
-`$<<`, `$>>`: (since Millfork 0.3.22)  
+`<<'`, `>>'`: (deprecated form)  
-`byte <<' constant byte`
+`byte $<< constant byte`
 
 ## Comparison operators
 
@@ -201,8 +201,8 @@ An expression of form `a[f()] += b` may call `f` an undefined number of times.
 `mutable word = word`  
 `mutable long = long`
 
-* `+=`, `+'=`, `|=`, `^=`, `&=`: modification in place  
+* `+=`, `$+=`, `|=`, `^=`, `&=`: modification in place  
-`$+=` (since Millfork 0.3.22)   
+`+'=` (deprecated form)   
 `mutable byte += byte`  
 `mutable word += word`  
 `mutable trivial long += long`
@@ -212,14 +212,14 @@ An expression of form `a[f()] += b` may call `f` an undefined number of times.
 `mutable word <<= byte`  
 `mutable trivial long <<= byte`
 
-* `<<'=`, `>>'=`: decimal shift in place  
+* `$<<=`, `$>>=`: decimal shift in place  
-`$<<=`, `$>>=` (since Millfork 0.3.22)  
+`<<'=`, `>>'=` (deprecated form)  
-`mutable byte <<'= constant byte`  
+`mutable byte $<<= constant byte`  
-`mutable word <<'= constant byte`  
+`mutable word $<<= constant byte`  
-`mutable trivial long <<'= constant byte`
+`mutable trivial long $<<= constant byte`
 
-* `-=`, `-'=`: subtraction in place  
+* `-=`, `$-=`: subtraction in place  
-`$-=` (since Millfork 0.3.22)  
+`-'=` (deprecated form)  
 `mutable byte -= byte`  
 `mutable word -= simple word`  
 `mutable trivial long -= simple long`
@@ -230,9 +230,9 @@ An expression of form `a[f()] += b` may call `f` an undefined number of times.
 `mutable word *= unsigned byte` (zpreg)
 `mutable word *= word` (zpreg)
 
-* `*'=`: decimal multiplication in place  
+* `$*=`: decimal multiplication in place  
-`$*=` (since Millfork 0.3.22)  
+`*'=` (deprecated form)  
-`mutable byte *'= constant byte`
+`mutable byte $*= constant byte`
 
 * `/=`, `%%=`: unsigned division and modulo in place  
 `mutable unsigned byte /= unsigned byte` (zpreg)  
@@ -291,9 +291,9 @@ but you can access its fields or take its pointer:
 
 * `nonet`: expansion of an 8-bit operation to a 9-bit operation  
 `nonet(byte + byte)`  
-`nonet(byte +' byte)`  
+`nonet(byte $+ byte)`  
 `nonet(byte << constant byte)`  
-`nonet(byte <<' constant byte)`  
+`nonet(byte $<< constant byte)`  
 Other kinds of expressions than the above (even `nonet(byte + byte + byte)`) will not work as expected.
 
 * `hi`, `lo`: most/least significant byte of a word  

docs/lang/predefined_constants.md

@@ -25,3 +25,5 @@
 * `byte segment.N.bank` – the value of `segment_N_bank` from the platform definition
 
 * `byte segment.N.fill` – the value of `segment_N_fill` from the platform definition
+
+* `this.function` – the alias of the current function (in macros, it resolves to the actual non-macro function that called the macro)

docs/lang/preprocessor.md

@@ -103,6 +103,8 @@ Some libraries may require that some of these be defined.
 
 * `KEYBOARD` – 1 if the target has a keyboard, 0 otherwise
 
+* `DISPLACED_MAIN` – set this to 1 if the `main` function is in a very unusual location for the target
+
 * `USE_MOUSE_MBM` –  set this to 1 if you want to enable middle button support for the mouse. 
 
 * `JOYSTICKS` – the maximum number of joysticks using standard hardware configurations, may be 0
@@ -151,11 +153,40 @@ The `if` function returns its second parameter if the first parameter is defined
     // prints 500:
     #infoeval if(0, 400, 500)
 
-TODO   
+The `min` and `max` functions return the smallest or largest parameter respectively. They support any number of arguments:
-`not`, `lo`, `hi`, `min`, `max` `+`, `-`, `*`, `|`, `&`, `^`, `||`, `&&`, `<<`, `>>`,`==`, `!=`, `>`, `>=`, `<`, `<=`
+
+    // prints 400:
+    #infoeval min(400, 500, 600)
+    // prints 500:
+    #infoeval max(400, 500)
+
+The following Millfork operators and functions are also available in the preprocessor:  
+`not`, `lo`, `hi`, `+`, `-`, `*`, `|`, `&`, `^`, `||`, `&&`, `<<`, `>>`,`==`, `!=`, `>`, `>=`, `<`, `<=`
 
 The following Millfork operators and functions are not available in the preprocessor:  
-`+'`, `-'`, `*'`, `<<'`, `>>'`, `:`, `>>>>`, `nonet`, all the assignment operators
+`$+`, `$-`, `$*`, `$<<`, `$>>`, `:`, `>>>>`, `nonet`, all the assignment operators
+
+
+### Character literals
+
+Preprocessor supports character literals. By default, they are interpreted in the default encoding,
+but you can suffix them with other encodings.
+
+    // usually prints 97:
+    #infoeval 'a'
+    // prints 97:
+    #infoeval 'a'ascii
+
+Exceptionally, you can suffix the character literal with `utf32`.
+This gives the literal the value of the Unicode codepoint of the character:
+
+    // may print 94, 96, 112, 173, 176, 184, 185, 222, 227, 234, 240, something else, or even fail to compile:
+    #infoeval 'π'
+    // prints 960:
+    #infoeval 'π'utf32
+
+Escape sequences are supported, as per encoding. `utf32` pseudoencoding supports the same escape sequences as `utf8`.
+
 
 ### `#template`
 

docs/lang/suffixes.md

@@ -10,9 +10,9 @@ These suffixes can be only applied to arithmetic or pointer variables:
 
 * `.hi` – the most significant byte of a two-byte variable (word, pointer) (use `hi(_)` for arbitrary expressions)
 
-* `.loword` – the least significant byte of a three- or four-byte variable
+* `.loword` – the least significant word of a three- or four-byte variable
 
-* `.hiword` – the most significant byte of a three- or four-byte variable
+* `.hiword` – the most significant word of a three- or four-byte variable
 
 * `.b0`, `.b1` etc. – the given byte of the multi-byte arithmetic variable, with `.b0` being the least significant byte
 

docs/lang/syntax.md

@@ -50,7 +50,7 @@ or a top level of a function (*local* variables).
 
 Syntax:
 
-`[segment(<segment>)] [volatile] [<storage>] <type> <name> [@<address>] [= <initial_value>]`
+`[segment(<segment>)] [volatile] [<storage>] <type> <name> [<optimization hints>] [@<address>] [= <initial_value>]`
 
 Examples:
 
@@ -69,6 +69,8 @@ Volatile variables cannot be declared as `register` or `stack`.
 * `<storage>` can be only specified for local variables. It can be either `stack`, `static`, `register` or nothing.
 `register` is only a hint for the optimizer. 
 See [the description of variable storage](../abi/variable-storage.md).
+  
+* `<optimization hints>` is a list of [optimization hints](./hints.md), separated by spaces
 
 * `<address>` is a constant expression that defines where in the memory the variable will be located. 
 If not specified, it will be located according to the usual allocation rules. 

docs/lang/text.md

@@ -26,6 +26,8 @@ TODO: document the file format.
 
 * `oldpetscii` or `oldpet` – old PETSCII (Commodore PET with newer ROMs)
 
+* `geos_de` – text encoding used by the German version of GEOS for C64
+
 * `cbmscr` or `petscr` – Commodore screencodes
 
 * `cbmscrjp` or `petscrjp` – Commodore screencodes as used on Japanese versions of Commodore 64
@@ -89,7 +91,7 @@ DOS codepages 437, 850, 851, 852, 855, 858, 866
 
 * `kamenicky` – Kamenický encoding
 
-* `cp1250`, `cp1251`, `cp1252` – Windows codepages 1250, 1251, 1252
+* `cp1250`, `cp1251`, `cp1252`, `cp1253`, `cp1254`, `cp1257` – Windows codepages 1250, 1251, 1252, 1253, 1254, 1257
 
 * `msx_intl`, `msx_jp`, `msx_ru`, `msx_br` – MSX character encoding, International, Japanese, Russian and Brazilian respectively
 
@@ -132,6 +134,8 @@ English, Japanese, Spanish/Italian and French/German respectively
 
 * `utf16be`, `utf16le` – UTF-16BE and UTF-16LE
 
+* `utf32be`, `utf32le` – UTF-32BE and UTF-32LE
+
 When programming for Commodore,
 use `petscii` for strings you're printing using standard I/O routines
 and `petsciiscr` for strings you're copying to screen memory directly.
@@ -163,10 +167,12 @@ The exact value of `{nullchar}` is encoding-dependent:
     * in the `zx80` encoding it's `{x01}`,
     * in the `zx81` encoding it's `{x0b}`,
     * in the `petscr` and `petscrjp` encodings it's `{xe0}`,
+    * in the `apple2e` encoding it's `{x7f}`,
     * in the `atasciiscr` encoding it's `{xdb}`,
     * in the `pokemon1*` encodings it's `{x50}`,
     * in the `cocoscr` encoding it's exceptionally two bytes: `{xd0}`
     * in the `utf16be` and `utf16le` encodings it's exceptionally two bytes: `{x00}{x00}`
+    * in the `utf32be` and `utf32le` encodings it's exceptionally four bytes: `{x00}{x00}{x00}{x00}`
     * in other encodings it's `{x00}` (this may be a subject to change in future versions).
 
 ##### Available only in some encodings
@@ -211,6 +217,7 @@ Encoding | lowercase letters | backslash | currencies | intl | card suits
 `petscr`            | yes¹ | no  | £    | none      | yes¹  
 `petjp`             | no   | no  | ¥    | katakana³ | yes³  
 `petscrjp`          | no   | no  | ¥    | katakana³ | yes³  
+`geos_de`           | yes  | no  |      |           | no  
 `sinclair`, `bbc`   | yes  | yes | £    | none      | no  
 `zx80`, `zx81`      | no   | no  | £    | none      | no  
 `apple2`            | no   | yes |      | none      | no  
@@ -273,6 +280,7 @@ Encoding | new line | braces | backspace | cursor movement | text colour | rever
 `origpet`           | yes | no  | no  | yes | no  | yes | no  
 `oldpet`            | yes | no  | no  | yes | no  | yes | no  
 `petscr`, `petscrjp`| no  | no  | no  | no  | no  | no  | no  
+`geos_de`           | no  | no  | no  | no  | no  | yes | no
 `sinclair`          | yes | yes | no  | yes | yes | yes | yes  
 `zx80`,`zx81`       | yes | no  | yes | yes | no  | no  | no  
 `ascii`, `iso_*`    | yes | yes | yes | no  | no  | no  | no  

examples/README.md

@@ -3,6 +3,12 @@
 The examples showcased here are designed to compile with a compiler built from the newest sources.
 If you are using a release version of the compiler, consider browsing the older versions of the examples:
 
+* [for version 0.3.28](https://github.com/KarolS/millfork/tree/v0.3.28/examples)
+
+* [for version 0.3.26](https://github.com/KarolS/millfork/tree/v0.3.26/examples)
+
+* [for version 0.3.24](https://github.com/KarolS/millfork/tree/v0.3.24/examples)
+
 * [for version 0.3.22](https://github.com/KarolS/millfork/tree/v0.3.22/examples)
 
 * [for version 0.3.18](https://github.com/KarolS/millfork/tree/v0.3.18/examples)

include/c128_kernal.mfk

@@ -6,7 +6,7 @@
 
 // CHROUT. Write byte to default output. (If not screen, must call OPEN and CHKOUT beforehands.)
 // Input: A = Byte to write.
-asm void chrout(byte register(a) char) @$FFD2 extern
+asm void chrout(byte register(a) char) !preserves_a !preserves_x !preserves_y @$FFD2 extern
 
 asm void putchar(byte register(a) char) {
     JSR chrout

include/c264_kernal.mfk

@@ -5,7 +5,7 @@
 
 // CHROUT. Write byte to default output. (If not screen, must call OPEN and CHKOUT beforehands.)
 // Input: A = Byte to write.
-asm void chrout(byte register(a) char) @$FFD2 extern
+asm void chrout(byte register(a) char) !preserves_a !preserves_x !preserves_y @$FFD2 extern
 
 asm void putchar(byte register(a) char) {
     JSR chrout

include/c64_easyflash.mfk

@@ -2,7 +2,7 @@ import err
 
 inline asm void switch_hirom(byte register(a) bank) {
     ? and #$3F
-    ! sta $DE01
+    ! sta $DE00
     ? rts
 }
 

include/c64_kernal.mfk

@@ -2,7 +2,7 @@
 
 // CHROUT. Write byte to default output. (If not screen, must call OPEN and CHKOUT beforehands.)
 // Input: A = Byte to write.
-asm void chrout(byte register(a) char) @$FFD2 extern
+asm void chrout(byte register(a) char) !preserves_a !preserves_x !preserves_y @$FFD2 extern
 
 // CHRIN. Read byte from default input (for keyboard, read a line from the screen). (If not keyboard, must call OPEN and CHKIN beforehands.)
 // Output: A = Byte read.

include/c64_sid.mfk

@@ -10,7 +10,7 @@ word sid_v1_freq  @$D400
 word sid_v1_pulse @$D402
 byte sid_v1_cr    @$D404
 byte sid_v1_ad    @$D405
-byte sid_v1_sr    @$D409
+byte sid_v1_sr    @$D406
 
 word sid_v2_freq  @$D407
 word sid_v2_pulse @$D409

include/cbm/basic_loader.mfk

@@ -0,0 +1,31 @@
+#template $ADDR$
+
+#if not(CBM)
+#warn cbm/basic_loader module should be only used on Commodore targets
+#endif
+
+const array _basic_loader @ $ADDR$ = [
+#if DISPLACED_MAIN
+    @word_le [
+        $ADDR$ + 0xB
+    ],
+#else
+    @word_le [
+        $ADDR$ + if(main.addr >= 10000, 1/0, 0xA) // use -D DISPLACED_MAIN=1 if you get an error here
+    ],
+#endif
+    10,
+    0,
+    $9e,
+#if DISPLACED_MAIN
+    $30 + (main.addr/10000)%%10,
+#endif
+    $30 + (main.addr/1000)%%10,
+    $30 + (main.addr/100)%%10,
+    $30 + (main.addr/10)%%10,
+    $30 + (main.addr/1)%%10,
+    0,
+    0,
+    0
+    ]
+

include/encoding/apple2.tbl

@@ -7,7 +7,7 @@ C0-DF=@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_
 
 a-z=C1
 
-{q}=02
+{q}=A2
-{apos}=07
+{apos}=A7
 {nbsp}=40
 {n}=8D

include/encoding/apple2c.tbl

@@ -13,3 +13,4 @@ EOT=00
 {apos}=27
 {lbrace}=7b
 {rbrace}=7d
+{pound}=5c

include/encoding/apple2e.tbl

@@ -7,8 +7,8 @@ EOT=7F
 20-3f=@abcdefghijklmnopqrstuvwxyz[\]^_
 60-7e=πABCDEFGHIJKLMNOPQRSTUVWXYZ{|}~
 
-{q}=22
+{q}=02
-{apos}=27
+{apos}=07
 {lbrace}=7b
 {rbrace}=7d
 {pi}=60

include/encoding/apple2gs.tbl

@@ -9,4 +9,4 @@ E0-FE=`abcdefghijklmnopqrstuvwxyz{\}~
 {q}=A2
 {apos}=A7
 {lbrace}=FB
-{rbrace}=FC
+{rbrace}=FD

include/encoding/cp1250.tbl

@@ -26,6 +26,7 @@ f0-ff=đńňóôőö÷řůúűüýţ˙
 {apos}=27
 {lbrace}=7b
 {rbrace}=7d
+{euro}=80
 {copy}=a9
 {ss}=df
 {nbsp}=A0

include/encoding/cp1251.tbl

@@ -23,6 +23,7 @@ f0-ff=рстуфхцчшщъыьэюя
 {apos}=27
 {lbrace}=7b
 {rbrace}=7d
+{euro}=88
 {copy}=a9
 {nbsp}=A0
 {shy}=AD

include/encoding/cp1252.tbl

@@ -25,6 +25,7 @@ f0-ff=ðñòóôõö÷øùúûüýþÿ
 {apos}=27
 {lbrace}=7b
 {rbrace}=7d
+{euro}=80
 {cent}=a2
 {pound}=a3
 {yen}=a5

include/encoding/cp1253.tbl

@@ -0,0 +1,39 @@
+NAME=CP1253
+EOT=00
+
+20=U+0020
+21-3f=!"#$%&'()*+,-./0123456789:;<=>?
+40-5f=@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_
+60-7e=`abcdefghijklmnopqrstuvwxyz{|}~
+80=€
+82-87=‚ƒ„…†‡
+89=‰
+8b=‹
+91-97=‘’“”•–—
+99=™
+9b=›
+a1-ac=΅Ά£¤¥¦§¨©ͺ«¬
+ae-af=®―
+b0-bf=°±²³΄µ¶·ΈΉΊ»Ό½ΎΏ
+c0-cf=ΐΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟ
+d0-d1=ΠΡ
+d3-df=ΣΤΥΦΧΨΩΪΫάέήί
+e0-ef=ΰαβγδεζηθικλμνξο
+f0-fe=πρςστυφχψωϊϋόύώ
+
+
+
+{b}=08
+{t}=09
+{n}=0d0a
+{q}=22
+{apos}=27
+{lbrace}=7b
+{rbrace}=7d
+{euro}=80
+{pound}=a3
+{yen}=a5
+{copy}=a9
+{pi}=f0
+{nbsp}=A0
+{shy}=AD

include/encoding/cp1254.tbl

@@ -0,0 +1,34 @@
+NAME=CP1254
+EOT=00
+
+20=U+0020
+21-3f=!"#$%&'()*+,-./0123456789:;<=>?
+40-5f=@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_
+60-7e=`abcdefghijklmnopqrstuvwxyz{|}~
+80=€
+82-8c=‚ƒ„…†‡ˆ‰Š‹Œ
+91-9c=‘’“”•–—˜™š›œ
+9f=Ÿ
+a1-ac=¡¢£¤¥¦§¨©ª«¬
+ae-af=®¯
+b0-bf=°±²³´µ¶·¸¹º»¼½¾¿
+c0-cf=ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏ
+d0-df=ĞÑÒÓÔÕÖ×ØÙÚÛÜİŞß
+e0-ef=àáâãäåæçèéêëìíîï
+f0-ff=ğñòóôõö÷øùúûüışÿ
+
+{b}=08
+{t}=09
+{n}=0d0a
+{q}=22
+{apos}=27
+{lbrace}=7b
+{rbrace}=7d
+{euro}=80
+{cent}=a2
+{pound}=a3
+{yen}=a5
+{copy}=a9
+{ss}=df
+{nbsp}=A0
+{shy}=AD

include/encoding/cp1257.tbl

@@ -0,0 +1,36 @@
+NAME=CP1257
+EOT=00
+
+20=U+0020
+21-3f=!"#$%&'()*+,-./0123456789:;<=>?
+40-5f=@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_
+60-7e=`abcdefghijklmnopqrstuvwxyz{|}~
+80=€
+82-8c=‚ƒ„…†‡ˆ‰Š‹Œ
+8d-8f=¨ˇ¸
+91-9c=‘’“”•–—˜™š›œ
+9e-9f=¯˛
+a1-ac=¡¢£¤¥¦§Ø©Ŗ«¬
+ae-af=®Æ
+b0-bf=°±²³´µ¶·ø¹ŗ»¼½¾æ
+c0-cf=ĄĮĀĆÄÅĘĒČÉŹĖĢĶĪĻ
+d0-df=ŠŃŅÓŌÕÖ×ŲŁŚŪÜŻŽß
+e0-ef=ąįāćäåęēčéźėģķīļ
+f0-ff=šńņóōõö÷ųłśūüżž˙
+
+
+{b}=08
+{t}=09
+{n}=0d0a
+{q}=22
+{apos}=27
+{lbrace}=7b
+{rbrace}=7d
+{euro}=80
+{cent}=a2
+{pound}=a3
+{yen}=a5
+{copy}=a9
+{ss}=df
+{nbsp}=A0
+{shy}=AD

include/encoding/cp437.tbl

@@ -27,4 +27,5 @@ F0-FE=≡±≥≤⌠⌡÷≈°∙·√ⁿ²■
 {pound}=9c
 {yen}=9d
 {ss}=e1
+{pi}=e3
 {nbsp}=FF

include/encoding/cp850.tbl

@@ -23,6 +23,7 @@ F1-FE=±‗¾¶§÷¸°¨·¹³²■
 {apos}=27
 {lbrace}=7b
 {rbrace}=7d
+{copy}=b8
 {cent}=BD
 {pound}=9c
 {yen}=BE

include/encoding/cp851.tbl

@@ -24,6 +24,7 @@ F1-FE=±υφχ§ψ¸°¨ωϋΰώ■
 {apos}=27
 {lbrace}=7b
 {rbrace}=7d
+{pound}=9c
 {ss}=D7
 {nbsp}=FF
 {shy}=F0

include/encoding/cp858.tbl

@@ -25,6 +25,7 @@ F1-FE=±‗¾¶§÷¸°¨·¹³²■
 {rbrace}=7d
 {cent}=BD
 {pound}=9c
+{copy}=b8
 {yen}=BE
 {euro}=D5
 {ss}=e1

include/encoding/cpc_da.tbl

@@ -19,6 +19,9 @@ fe-ff=↕↔
 {apos}=27
 {lbrace}=7b
 {rbrace}=7d
+{pound}=a3
+{copy}=a4
+{pi}=b8
 {AE}=5b
 {OE}=5c
 {AA}=5d

include/encoding/cpc_en.tbl

@@ -19,3 +19,6 @@ fe-ff=↕↔
 {apos}=27
 {lbrace}=7b
 {rbrace}=7d
+{pound}=a3
+{copy}=a4
+{pi}=b8

include/encoding/cpc_es.tbl

@@ -19,3 +19,5 @@ fe-ff=↕↔
 {apos}=27
 {lbrace}=7b
 {rbrace}=7d
+{copy}=a4
+{pi}=b8

include/encoding/cpc_fr.tbl

@@ -20,3 +20,6 @@ fe-ff=↕↔
 {apos}=27
 {lbrace}=7b
 {rbrace}=7d
+{pound}=a3
+{copy}=a4
+{pi}=b8

include/encoding/ebcdic.tbl

@@ -24,3 +24,4 @@ F0-F9=0123456789
 {q}=7F
 {lbrace}=C0
 {rbrace}=D0
+{cent}=4A

include/encoding/geos_de.tbl

@@ -0,0 +1,20 @@
+NAME=GEOS-DE
+EOT=00
+
+20=U+0020
+21-3f=!"#$%&'()*+,-./0123456789:;<=>?
+40-5f=§ABCDEFGHIJKLMNOPQRSTUVWXYZÄÖÜ^_
+60-7e=`abcdefghijklmnopqrstuvwxyzäöüß
+
+{b}=08
+{t}=09
+{n}=0d0a
+{q}=22
+{apos}=27
+{AE}=5b
+{OE}=5c
+{UE}=5d
+{ae}=7b
+{oe}=7c
+{ue}=7d
+{ss}=7e

include/encoding/iso8859_3.tbl

@@ -27,3 +27,4 @@ f1-ff=ñòóôġö÷ĝùúûüŭŝ˙
 {ss}=df
 {nbsp}=A0
 {shy}=AD
+{pound}=A3

include/encoding/kamenicky.tbl

@@ -24,4 +24,5 @@ F0-FE=≡±≥≤⌠⌡÷≈°∙·√ⁿ²■
 {lbrace}=7b
 {rbrace}=7d
 {ss}=e1
+{pi}=e3
 {nbsp}=FF

include/encoding/koi8f.tbl

@@ -14,6 +14,7 @@ EOT=00
 {lbrace}=7b
 {rbrace}=7d
 {nbsp}=a0
+{copy}=98
 •=95
 
 b0=№

include/encoding/koi8r.tbl

@@ -14,6 +14,7 @@ EOT=00
 {lbrace}=7b
 {rbrace}=7d
 {nbsp}=9a
+{copy}=bf
 
 80-8f=─│┌┐└┘├┤┬┴┼▀▄█▌▐
 90-99=░▒▓⌠■∙√≈≤≥

include/encoding/koi8ru.tbl

@@ -14,6 +14,7 @@ EOT=00
 {lbrace}=7b
 {rbrace}=7d
 {nbsp}=9a
+{copy}=bf
 
 80-8f=─│┌┐└┘├┤┬┴┼▀▄█▌▐
 90-99=░▒▓“■∙”—№™

include/encoding/koi8t.tbl

@@ -14,6 +14,7 @@ EOT=00
 {lbrace}=7b
 {rbrace}=7d
 {shy}=8d
+{copy}=bf
 
 
 

include/encoding/koi8u.tbl

@@ -14,6 +14,7 @@ EOT=00
 {lbrace}=7b
 {rbrace}=7d
 {nbsp}=9a
+{copy}=bf
 
 80-8f=─│┌┐└┘├┤┬┴┼▀▄█▌▐
 90-99=░▒▓⌠■∙√≈≤≥

include/encoding/macroman.tbl

@@ -29,5 +29,6 @@ f1-ff=ÒÚÛÙıˆ˜¯˘˙˚¸˝˛ˇ
 {ss}=a7
 {nbsp}=CA
 {euro}=DB
+{pi}=b9
 €=DB
 U+F8FF=F0

include/encoding/mazovia.tbl

@@ -26,4 +26,5 @@ F0-FE=≡±≥≤⌠⌡÷≈°∙·√ⁿ²■
 {cent}=9b
 {yen}=9d
 {ss}=e1
+{pi}=e3
 {nbsp}=FF

include/encoding/pcw.tbl

@@ -55,3 +55,8 @@ f0-ff=äëïöüçæåøñãõ⇒⇐⇔≡
 {lbrace}=7b
 {rbrace}=7d
 {pi}=1b18
+{pound}=a3
+{copy}=a4
+{yen}=bd
+{cent}=b1
+{ss}=ba

include/encoding/pokemon1en.tbl

@@ -23,6 +23,7 @@ F0-FF=₽×./,♀0123456789
 {ot}=BE
 {'v}=BF
 {hav}=BF
+{apos}=E0
 {'r}=E4
 {ar}=E4
 {'m}=E5

include/encoding/pokemon1es.tbl

@@ -22,6 +22,7 @@ F0-FF=₽×./,♀0123456789
 {'t}=DD
 {'v}=DE
 
+{apos}=E0
 {PK}=E1
 {pk}=E1
 {MN}=E2

include/encoding/pokemon1fr.tbl

@@ -13,6 +13,7 @@ E6-E8=?!.
 EC-EF=▷▶▼♂
 F0-FF=₽×./,♀0123456789
 
+{ss}=be
 {c'}=d4
 {ce}=d4
 {d'}=d5
@@ -37,6 +38,7 @@ F0-FF=₽×./,♀0123456789
 {u'}=de
 {ue}=de
 {y'}=df
+{apos}=e0
 
 {PK}=E1
 {pk}=E1

include/encoding/utf32be.tbl

@@ -0,0 +1,2 @@
+NAME=UTF-32BE
+BUILTIN=UTF-32BE

include/encoding/utf32le.tbl

@@ -0,0 +1,2 @@
+NAME=UTF-32LE
+BUILTIN=UTF-32LE

include/gb_header_small.mfk

@@ -4,7 +4,7 @@
 
 #pragma zilog_syntax
 
-array __header @ $100 = [
+const array __header @ $100 = [
     $00, $C3, $50, $01, $CE, $ED, $66, $66,   $CC, $0D, $00, $0B, $03, $73, $00, $83,
     $00, $0C, $00, $0D, $00, $08, $11, $1F,   $88, $89, $00, $0E, $DC, $CC, $6E, $E6,
     $DD, $DD, $D9, $99, $BB, $BB, $67, $63,   $6E, $0E, $EC, $CC, $DD, $DC, $99, $9F,

include/gb_joy.mfk

@@ -38,9 +38,9 @@ void read_joy() {
         ld a,(reg_joypad)
         ld a,(reg_joypad)
     }
-    byte tmp
+    
     tmp = reg_joypad ^ $ff
-    input_a = (tmp & 1) >> 0
+    input_a = (tmp & 1) // >> 0  
     input_b = (tmp & 2) >> 1
     input_select = (tmp & 4) >> 2
     input_start = (tmp & 8) >> 3

include/i80/i80_math.mfk

@@ -11,6 +11,12 @@ inline asm byte __mul_u8u8u8() {
     ? LD A, E
     ? RET
 }
+#elseif CPUFEATURE_R800
+inline asm byte __mul_u8u8u8() {
+    ? MULUB A,D
+    ? LD A,L
+    ? RET
+}
 #elseif CPUFEATURE_Z80 || CPUFEATURE_GAMEBOY
 //A = A * D
 noinline asm byte __mul_u8u8u8() {
@@ -89,6 +95,16 @@ __divmod_u16u8u16u8_skip:
     ? RET
 }
 
+
+#if CPUFEATURE_R800
+inline asm word __mul_u16u8u16() {
+    ? LD L,A
+    ? LD H,0
+    ? MULUW HL,DE
+    ? RET
+}
+#else
+// HL=A*DE
 noinline asm word __mul_u16u8u16() {
     ? LD HL,0
     ? LD B,8
@@ -113,8 +129,17 @@ __mul_u16u8u16_skip:
 #endif
     ? RET
 }
+#endif
 
-#if CPUFEATURE_Z80 || CPUFEATURE_GAMEBOY
+
+#if CPUFEATURE_R800
+inline asm word __mul_u16u16u16() {
+    ? EX DE,HL
+    ? MULUW HL,BC
+    ? RET
+}
+#elseif CPUFEATURE_Z80 || CPUFEATURE_GAMEBOY
+// HL=BC*DE
 noinline asm word __mul_u16u16u16() {
     LD HL,0
     LD A,16

include/loader_0401.mfk

@@ -1,19 +1 @@
-#if not(CBM)
+import cbm/basic_loader<$401>
-#warn loader_0401 module should be only used on Commodore targets
-#endif
-
-const array _basic_loader @$401 = [
-    $0b,
-    4,
-    10,
-    0,
-    $9e,
-    $31,
-    $30,
-    $33,
-    $37,
-    0,
-    0,
-    0
-    ]
-

include/loader_0801.mfk

@@ -1,19 +1 @@
-#if not(CBM)
+import cbm/basic_loader<$801>
-#warn loader_0801 module should be only used on Commodore targets
-#endif
-
-const array _basic_loader @$801 = [
-    $0b,
-    $08,
-    10,
-    0,
-    $9e,
-    $32,
-    $30,
-    $36,
-    $31,
-    0,
-    0,
-    0
-    ]
-

include/loader_0801_16bit.mfk

@@ -22,4 +22,5 @@ asm void __init_16bit() @$80D {
     clc
     xce
     sep #$30
-}
+    jmp main
+}

include/loader_1001.mfk

@@ -1,19 +1 @@
-#if not(CBM)
+import cbm/basic_loader<$1001>
-#warn loader_1001 module should be only used on Commodore targets
-#endif
-
-const array _basic_loader @$1001 = [
-    $0b,
-    $10,
-    10,
-    0,
-    $9e,
-    $34,
-    $31,
-    $30,
-    $39,
-    0,
-    0,
-    0
-    ]
-

include/loader_1201.mfk

@@ -1,19 +1 @@
-#if not(CBM)
+import cbm/basic_loader<$1201>
-#warn loader_1201 module should be only used on Commodore targets
-#endif
-
-const array _basic_loader @$1201 = [
-    $0b,
-    $12,
-    10,
-    0,
-    $9e,
-    $34,
-    $36,
-    $32,
-    $31,
-    0,
-    0,
-    0
-    ]
-

include/loader_1c01.mfk

@@ -1,19 +1 @@
-#if not(CBM)
+import cbm/basic_loader<$1c01>
-#warn loader_1c01 module should be only used on Commodore targets
-#endif
-
-const array _basic_loader @$1C01 = [
-    $0b,
-    $1C,
-    10,
-    0,
-    $9e,
-    $37,
-    $31,
-    $38,
-    $31,
-    0,
-    0,
-    0
-    ]
-

include/m6809/m6809_math.mfk

@@ -3,7 +3,7 @@
 #warn m6809_math module should be used only on 6809-like targets
 #endif
 
-noinline asm word __mul_u16u16u16(word register(x) x, word register(d) d) {
+noinline asm word __mul_u16u16u16(word register(x) x, word register(d) d) !preserves_y !preserves_u {
     pshs d,x
     exg d,x
     lda ,s
@@ -26,7 +26,7 @@ noinline asm word __mul_u16u16u16(word register(x) x, word register(d) d) {
 }
 
 // returns p/q: quotient in A, remainder in B
-noinline asm word __divmod_u8u8u8u8(word register(a) p, word register(b) q) {
+noinline asm word __divmod_u8u8u8u8(word register(a) p, word register(b) q) !preserves_x !preserves_y !preserves_u {
     pshs b,cc
     ldb #8
     stb ,-s
@@ -47,7 +47,7 @@ noinline asm word __divmod_u8u8u8u8(word register(a) p, word register(b) q) {
 }
 
 // returns p/q: quotient in X, remainder in D
-noinline asm word __divmod_u16u16u16u16(word register(x) p, word register(d) q) {
+noinline asm word __divmod_u16u16u16u16(word register(x) p, word register(d) q) !preserves_y !preserves_u {
     pshs x,d,cc
     ldb #16
     pshs b

include/pet_kernal.mfk

@@ -6,7 +6,7 @@
 
 // CHROUT. Write byte to default output. (If not screen, must call OPEN and CHKOUT beforehands.)
 // Input: A = Byte to write.
-asm void putchar(byte register(a) char) @$FFD2 extern
+asm void putchar(byte register(a) char) !preserves_a !preserves_x !preserves_y @$FFD2 extern
 
 inline void new_line() {
     putchar(13)

include/platform/x16_experimental.ini

@@ -11,14 +11,21 @@ modules=loader_0801,x16_kernal,x16_hardware,c64_panic,stdlib
 
 [allocation]
 ; Let's not use the BASIC:
-zp_pointers=0-$7F
+; $00-$01 are used for bank switching
-segments=default,himem_00,himem_ff
+zp_pointers=$02-$7F
+segments=default,user,himem_00,himem_ff
 default_code_segment=default
 segment_default_start=$80D
 segment_default_codeend=$9eff
 segment_default_datastart=after_code
 segment_default_end=$9eff
 
+;1KB user space
+segment_user_start=$0400
+segment_user_codeend=$07ff
+segment_user_datastart=after_code
+segment_user_end=$07ff
+
 segment_himem_00_start=$a000
 segment_himem_00_codeend=$bfff
 segment_himem_00_datastart=after_code

include/vic20_kernal.mfk

@@ -6,7 +6,7 @@
 
 // CHROUT. Write byte to default output. (If not screen, must call OPEN and CHKOUT beforehands.)
 // Input: A = Byte to write.
-asm void chrout(byte register(a) char) @$FFD2 extern
+asm void chrout(byte register(a) char) !preserves_a !preserves_x !preserves_y @$FFD2 extern
 
 asm void putchar(byte register(a) char) {
     JSR chrout

include/zxspectrum.mfk

@@ -5,16 +5,16 @@
 
 #pragma zilog_syntax
 
-inline asm void putchar(byte register(a) char) {
+inline asm void putchar(byte register(a) char) !preserves_bc !preserves_de !preserves_hl {
     rst $10
     ? ret
 }
 
-inline void new_line() {
+inline void new_line() !preserves_bc !preserves_de !preserves_hl {
     putchar(13)
 }
 
-inline asm void set_border(byte register(a) colour) {
+inline asm void set_border(byte register(a) colour) !preserves_bc !preserves_de !preserves_hl {
     out (254),a
     ? ret
 }

millfork-udl.xml

@@ -19,11 +19,15 @@
                 += -= *= >>= <<=
                 +' -' *' <<' >>'
                 +'= -'= *'= <<'= >>'=
+                $+ $- $* $<< $>>
+                $+= $-= $*= $<<= $>>=
                 = ?
                 / %% /= %%=
                 > >= < <= != ==
                 | || |= ^ ^= & && &=
-                ( ) { } @ [ ] : # </Keywords>
+                ( ) { } @ [ ] : #
+                ; .
+            </Keywords>
             <Keywords name="Operators2"></Keywords>
             <Keywords name="Folders in code1, open">{</Keywords>
             <Keywords name="Folders in code1, middle"></Keywords>
@@ -38,10 +42,14 @@
                 void bool byte sbyte ubyte word farword pointer farpointer long word_be word_le long_be long_le file 
                 int8 int16 int24 int32 int40 int48 int56 int64
                 int72 int80 int88 int96 int104 int112 int120 int128
-                signed8 
+                signed8 signed16 signed24 signed32 signed40 signed48 signed56 signed64
+                signed72 signed80 signed88 signed96 signed104 signed112 signed120 signed128
                 unsigned8 unsigned16 unsigned24 unsigned32 unsigned40 unsigned48 unsigned56 unsigned64
                 unsigned72 unsigned80 unsigned88 unsigned96 unsigned104 unsigned112 unsigned120 unsigned128
-                array addr fast</Keywords>
+                array addr fast
+                clear_carry clear_zero clear_overflow clear_negative
+                set_carry set_zero set_overflow set_negative
+            </Keywords>
             <Keywords name="Keywords2">
                 import segment
                 if else for return while do asm extern break continue default goto label
@@ -54,9 +62,11 @@
                 utf8 utf16le utf16be latin0 latin9 iso8859_15 zx80 zx81 vectrex koi7n2 short_koi msx_intl msx_us msx_uk msx_de msx_fr msx_es msx_ru msx_jp msx_br
                 utf8z utf16lez utf16bez latin0z latin9z iso8859_15z zx80z zx81z vectrexz koi7n2z short_koiz msx_intlz msx_usz msx_ukz msx_dez msx_frz msx_esz msx_ruz msx_jpz msx_brz
                 until to downto parallelto paralleluntil
+                function
                 static stack ref const volatile inline noinline macro register kernal_interrupt interrupt align reentrant
                 hi lo sin cos tan call nonet 
-                false true nullptr</Keywords>
+                false true nullptr nullchar nullchar_scr
+            </Keywords>
             <Keywords name="Keywords4">&quot;sta &quot; &quot;lda &quot; &quot;jmp &quot; &quot;bit &quot; &quot;eor &quot; &quot;adc &quot; &quot;sbc &quot; &quot;ora &quot; &quot;and &quot; &quot;ldx &quot; &quot;ldy &quot; &quot;stx &quot; &quot;sty &quot; &quot;tax&quot; &quot;tay&quot; &quot;tya&quot; &quot;txa&quot; &quot;txs&quot; &quot;tsx&quot; &quot;sei&quot; &quot;cli&quot; &quot;clv&quot; &quot;clc&quot; &quot;cld&quot; &quot;sed&quot; &quot;sec&quot; &quot;bra &quot; &quot;beq &quot; &quot;bne &quot; &quot;bmi &quot; &quot;bpl &quot; &quot;bcc &quot; &quot;bcs &quot; &quot;bvs &quot; bvc &quot;  &quot;jsr &quot; rts&quot;  &quot;rti&quot; &quot;brk&quot; &quot;rol&quot; &quot;ror&quot; &quot;asl&quot; &quot;lsr&quot; &quot;inc &quot; &quot;dec &quot; &quot;cmp &quot; &quot;cpx &quot; &quot;cpy &quot; inx iny dex dey pla pha plp  hp phx plx phy ply &quot;stz &quot; &quot;ldz &quot; tza taz &quot;tsb &quot; &quot;trb &quot; ra   txy tyx pld plb phb phd phk xce&#x000D;&#x000A;&#x000D;&#x000A;&quot;STA &quot; &quot;LDA &quot; &quot;JMP &quot; &quot;BIT &quot; &quot;EOR &quot; &quot;ADC &quot; &quot;SBC &quot; &quot;ORA &quot; &quot;AND &quot; &quot;LDX &quot; &quot;LDY &quot; &quot;STX &quot; &quot;STY &quot; &quot;TAX&quot; &quot;TAY&quot; &quot;TYA&quot; &quot;TXA&quot; &quot;TXS&quot; &quot;TSX&quot; &quot;SEI&quot; &quot;CLI&quot; &quot;CLV&quot; &quot;CLC&quot; &quot;CLD&quot; &quot;SED&quot; &quot;SEC&quot;   &quot;BEQ &quot; &quot;BRA &quot; &quot;BNE &quot; &quot;BMI &quot; &quot;BPL &quot; &quot;BCC &quot; &quot;BCS &quot; &quot;BVS &quot; BVC &quot;  &quot;JSR &quot; RTS&quot;  &quot;RTI&quot; &quot;BRK&quot; &quot;ROL&quot; &quot;ROR&quot; &quot;ASL&quot; &quot;LSR&quot; &quot;INC &quot; &quot;DEC &quot; &quot;CMP &quot; &quot;CPX &quot; &quot;CPY &quot; INX INY DEX DEY PLA PHA PLP  HP PHX PLX PHY PLY &quot;STZ &quot; &quot;LDZ &quot; TZA TAZ &quot;TSB &quot; &quot;TRB &quot; RA   TXY TYX PLD PLB PHB PHD PHK XCE</Keywords>
             <Keywords name="Keywords5">&quot;sbx &quot; &quot;isc &quot; &quot;dcp &quot; &quot;lax &quot; &quot;sax &quot; &quot;anc &quot; &quot;alr &quot; &quot;arr &quot; &quot;rra &quot; &quot;rla &quot; &quot;lxa &quot; &quot;ane &quot; &quot;xaa &quot;&#x000D;&#x000A;&quot;SBX &quot; &quot;ISC &quot; &quot;DCP &quot; &quot;LAX &quot; &quot;SAX &quot; &quot;ANC &quot; &quot;ALR &quot; &quot;ARR &quot; &quot;RRA &quot; &quot;RLA &quot; &quot;LXA &quot; &quot;ANE &quot; &quot;XAA &quot;</Keywords>
             <Keywords name="Keywords6"></Keywords>

mkdocs.yml

@@ -35,6 +35,7 @@ nav:
     - Inline 8080/LR35902/Z80 assembly: lang/assemblyz80.md
     - Inline 6809 assembly: lang/assembly6809.md
     - Reentrancy guidelines: lang/reentrancy.md
+    - Optimization hints: lang/hints.md
     - List of keywords: lang/keywords.md
   - Library reference:
     - stdlib module: stdlib/stdlib.md

src/main/resources/META-INF/native-image/reflect-config.json

@@ -17,6 +17,11 @@
   "allDeclaredFields":true,
   "allPublicMethods":true
 },
+{
+  "name":"millfork.assembly.m6809.MOpcode$",
+  "allDeclaredFields":true,
+  "allPublicMethods":true
+},
 {
   "name":"org.apache.commons.logging.LogFactory"
 },

src/main/scala/millfork/CompilationOptions.scala

@@ -45,7 +45,7 @@ case class CompilationOptions(platform: Platform,
       EmitIntel8085Opcodes, EmitIntel8080Opcodes, UseIxForStack, UseIntelSyntaxForInput, UseIntelSyntaxForOutput)
 
     if (CpuFamily.forType(platform.cpu) != CpuFamily.I80) invalids ++= Set(
-      EmitExtended80Opcodes, EmitZ80Opcodes, EmitSharpOpcodes, EmitEZ80Opcodes, EmitZ80NextOpcodes,
+      EmitExtended80Opcodes, EmitZ80Opcodes, EmitSharpOpcodes, EmitEZ80Opcodes, EmitZ80NextOpcodes, EmitR800Opcodes,
       UseIyForStack, UseIxForScratch, UseIyForScratch, UseShadowRegistersForInterrupts)
 
     if (CpuFamily.forType(platform.cpu) != CpuFamily.M6809) invalids ++= Set(
@@ -172,6 +172,11 @@ case class CompilationOptions(platform: Platform,
             log.error("Extended 8080-like opcodes enabled for architecture that doesn't support them")
           }
         }
+        if (flags(EmitR800Opcodes)) {
+          if (platform.cpu != R800) {
+            log.error("R800 opcodes enabled for architecture that doesn't support them")
+          }
+        }
         if (flags(EmitIntel8080Opcodes)) {
           if (!Intel8080Compatible(platform.cpu)) {
             log.error("Intel 8080 opcodes enabled for architecture that doesn't support them")
@@ -220,6 +225,7 @@ case class CompilationOptions(platform: Platform,
       "OPTIMIZE_IPO" -> toLong(flag(CompilationFlag.InterproceduralOptimization)),
       "CPUFEATURE_DECIMAL_MODE" -> toLong(flag(CompilationFlag.DecimalMode)),
       "CPUFEATURE_Z80" -> toLong(flag(CompilationFlag.EmitZ80Opcodes)),
+      "CPUFEATURE_R800" -> toLong(flag(CompilationFlag.EmitR800Opcodes)),
       "CPUFEATURE_EZ80" -> toLong(flag(CompilationFlag.EmitEZ80Opcodes)),
       "CPUFEATURE_8080" -> toLong(flag(CompilationFlag.EmitIntel8080Opcodes)),
       "CPUFEATURE_8085" -> toLong(flag(CompilationFlag.EmitIntel8085Opcodes)),
@@ -290,7 +296,7 @@ object CpuFamily extends Enumeration {
     import Cpu._
     cpu match {
       case Mos | StrictMos | Ricoh | StrictRicoh | Cmos | SC02 | Rockwell | Wdc | HuC6280 | CE02 | Sixteen => M6502
-      case Intel8080 | Intel8085 | StrictIntel8085 | Sharp | Z80 | StrictZ80 | EZ80 | Z80Next => I80
+      case Intel8080 | Intel8085 | StrictIntel8085 | Sharp | Z80 | StrictZ80 | R800 | EZ80 | Z80Next => I80
       case Intel8086 | Intel80186 => I86
       case Cpu.Motorola6809 => M6809
     }
@@ -368,6 +374,10 @@ object Cpu extends Enumeration {
     * The Zilog Z80 processor, without illegal instructions
     */
   val StrictZ80: Cpu.Value = Value
+  /**
+    * The R800 CPU (used in MSX Turbo-R)
+    */
+  val R800: Cpu.Value = Value
   /**
     * The Zilog eZ80 processor
     */
@@ -400,11 +410,11 @@ object Cpu extends Enumeration {
   /**
     * Processors that can run code for Zilog Z80
     */
-  val Z80Compatible: Set[Cpu.Value] = Set(Z80, StrictZ80, EZ80, Z80Next)
+  val Z80Compatible: Set[Cpu.Value] = Set(Z80, StrictZ80, R800, EZ80, Z80Next)
   /**
     * Processors that can run code for Intel 8080
     */
-  val Intel8080Compatible: Set[Cpu.Value] = Set(Intel8080, Intel8085, StrictIntel8085, Z80, StrictZ80, EZ80, Z80Next)
+  val Intel8080Compatible: Set[Cpu.Value] = Set(Intel8080, Intel8085, StrictIntel8085, Z80, StrictZ80, R800, EZ80, Z80Next)
   /**
     * Processors that can run code for Intel 8085
     */
@@ -419,14 +429,18 @@ object Cpu extends Enumeration {
     RegisterVariables,
     FunctionDeduplication,
     EnableBreakpoints,
+    UseOptimizationHints,
     GenericWarnings,
+    ByteOverflowWarning,
     UselessCodeWarning,
     BuggyCodeWarning,
     FallbackValueUseWarning,
+    BytePointerComparisonWarning,
     DeprecationWarning,
     NonZeroTerminatedLiteralWarning,
     CallToOverlappingBankWarning,
     DataMissingInOutputWarning,
+    UnsupportedOptimizationHintWarning,
   )
 
   private val mosAlwaysDefaultFlags = alwaysDefaultFlags
@@ -464,6 +478,8 @@ object Cpu extends Enumeration {
       i80AlwaysDefaultFlags ++ Set(EmitIntel8080Opcodes, EmitIntel8085Opcodes, UseIntelSyntaxForInput, UseIntelSyntaxForOutput)
     case StrictZ80 | Z80 =>
       i80AlwaysDefaultFlags ++ Set(EmitIntel8080Opcodes, EmitExtended80Opcodes, EmitZ80Opcodes, UseIxForStack, UseShadowRegistersForInterrupts)
+    case R800 =>
+      i80AlwaysDefaultFlags ++ Set(EmitIntel8080Opcodes, EmitExtended80Opcodes, EmitZ80Opcodes, UseIxForStack, UseShadowRegistersForInterrupts, EmitR800Opcodes)
     case Z80Next =>
       i80AlwaysDefaultFlags ++ Set(EmitIntel8080Opcodes, EmitExtended80Opcodes, EmitZ80Opcodes, UseIxForStack, UseShadowRegistersForInterrupts, EmitIllegals, EmitZ80NextOpcodes)
     case EZ80 =>
@@ -510,6 +526,7 @@ object Cpu extends Enumeration {
     case "strict2a07" => StrictRicoh
     case "z80" => Z80
     case "strictz80" => Z80
+    case "r800" => R800
     case "zx80next" => Z80Next
     case "z80next" => Z80Next
       // disabled for now:
@@ -558,9 +575,9 @@ object CompilationFlag extends Enumeration {
   EmitIllegals, DecimalMode, LenientTextEncoding, LineNumbersInAssembly, SourceInAssembly, EnableBreakpoints,
   // compilation options for MOS:
   EmitCmosOpcodes, EmitCmosNopOpcodes, EmitSC02Opcodes, EmitRockwellOpcodes, EmitWdcOpcodes, EmitHudsonOpcodes, Emit65CE02Opcodes, EmitEmulation65816Opcodes, EmitNative65816Opcodes,
-  PreventJmpIndirectBug, LargeCode, ReturnWordsViaAccumulator, SoftwareStack,
+  PreventJmpIndirectBug, LargeCode, ReturnWordsViaAccumulator, SoftwareStack, IdentityPage,
   // compilation options for I80
-  EmitIntel8080Opcodes, EmitIntel8085Opcodes, EmitExtended80Opcodes, EmitZ80Opcodes, EmitEZ80Opcodes, EmitSharpOpcodes, EmitZ80NextOpcodes,
+  EmitIntel8080Opcodes, EmitIntel8085Opcodes, EmitExtended80Opcodes, EmitZ80Opcodes, EmitR800Opcodes, EmitEZ80Opcodes, EmitSharpOpcodes, EmitZ80NextOpcodes,
   UseShadowRegistersForInterrupts,
   UseIxForStack, UseIyForStack,
   UseIxForScratch, UseIyForScratch,
@@ -582,15 +599,18 @@ object CompilationFlag extends Enumeration {
   SingleThreaded,
   // warning options
   GenericWarnings,
+  ByteOverflowWarning,
   UselessCodeWarning,
   BuggyCodeWarning,
   DeprecationWarning,
   FallbackValueUseWarning,
+  BytePointerComparisonWarning,
   ExtraComparisonWarnings,
   RorWarning,
   NonZeroTerminatedLiteralWarning,
   CallToOverlappingBankWarning,
   DataMissingInOutputWarning,
+  UnsupportedOptimizationHintWarning,
   FatalWarnings,
   // special options for internal compiler use
   EnableInternalTestSyntax,
@@ -598,14 +618,17 @@ object CompilationFlag extends Enumeration {
 
   val allWarnings: Set[CompilationFlag.Value] = Set(
     GenericWarnings,
+    ByteOverflowWarning,
     UselessCodeWarning,
     BuggyCodeWarning,
     DeprecationWarning,
     FallbackValueUseWarning,
+    BytePointerComparisonWarning,
     ExtraComparisonWarnings,
     NonZeroTerminatedLiteralWarning,
     CallToOverlappingBankWarning,
     DataMissingInOutputWarning,
+    UnsupportedOptimizationHintWarning,
   )
 
   val fromString: Map[String, CompilationFlag.Value] = Map(
@@ -618,6 +641,7 @@ object CompilationFlag extends Enumeration {
     "emit_65ce02" -> Emit65CE02Opcodes,
     "emit_huc6280" -> EmitHudsonOpcodes,
     "emit_z80" -> EmitZ80Opcodes,
+    "emit_r800" -> EmitR800Opcodes,
     "emit_ez80" -> EmitEZ80Opcodes,
     "emit_x80" -> EmitExtended80Opcodes,
     "emit_8080" -> EmitIntel8080Opcodes,
@@ -630,6 +654,7 @@ object CompilationFlag extends Enumeration {
     "u_stack" -> UseUForStack,
     "y_stack" -> UseYForStack,
     "software_stack" -> SoftwareStack,
+    "identity_page" -> IdentityPage,
     "use_shadow_registers_for_irq" -> UseShadowRegistersForInterrupts,
     "output_intel_syntax" -> UseIntelSyntaxForOutput,
     "input_intel_syntax" -> UseIntelSyntaxForInput,

src/main/scala/millfork/Context.scala

@@ -46,10 +46,24 @@ case class Context(errorReporting: Logger,
     if (isFlagSet(CompilationFlag.EmitEZ80Opcodes)) {
       addons += CompilationFlag.EmitZ80Opcodes -> true
     }
-    if (isFlagSet(CompilationFlag.EmitZ80Opcodes) || isFlagSet(CompilationFlag.EmitSharpOpcodes)) {
+    if (isFlagSet(CompilationFlag.EmitZ80NextOpcodes)) {
+      addons += CompilationFlag.EmitZ80Opcodes -> true
+    }
+    if (isFlagSet(CompilationFlag.EmitR800Opcodes)) {
+      addons += CompilationFlag.EmitZ80Opcodes -> true
+    }
+    if (isFlagSet(CompilationFlag.EmitEZ80Opcodes)
+      || isFlagSet(CompilationFlag.EmitZ80NextOpcodes)
+      || isFlagSet(CompilationFlag.EmitR800Opcodes)
+      || isFlagSet(CompilationFlag.EmitZ80Opcodes)
+      || isFlagSet(CompilationFlag.EmitSharpOpcodes)) {
       addons += CompilationFlag.EmitExtended80Opcodes -> true
     }
-    if (isFlagSet(CompilationFlag.EmitZ80Opcodes) || isFlagSet(CompilationFlag.EmitIntel8085Opcodes)) {
+    if (isFlagSet(CompilationFlag.EmitEZ80Opcodes)
+      || isFlagSet(CompilationFlag.EmitZ80NextOpcodes)
+      || isFlagSet(CompilationFlag.EmitR800Opcodes)
+      || isFlagSet(CompilationFlag.EmitZ80Opcodes)
+      || isFlagSet(CompilationFlag.EmitIntel8085Opcodes)) {
       addons += CompilationFlag.EmitIntel8080Opcodes -> true
     }
     if (isFlagSet(CompilationFlag.OptimizeForSpeed)) {

src/main/scala/millfork/DebugOutputFormat.scala

@@ -1,23 +1,37 @@
 package millfork
 
+import millfork.output.{BankLayoutInFile, FormattableLabel}
+
+import java.util.regex.Pattern
+import scala.collection.mutable
+import scala.util.control.Breaks.{break, breakable}
+
 /**
   * @author Karol Stasiak
   */
 
 object DebugOutputFormat {
   val map: Map[String, DebugOutputFormat] = Map(
+    "raw" -> RawDebugOutputFormat,
     "vice" -> ViceDebugOutputFormat,
     "nesasm" -> NesasmDebugOutputFormat,
     "fns" -> NesasmDebugOutputFormat,
     "fceux" -> FceuxDebugOutputFormat,
     "nl" -> FceuxDebugOutputFormat,
+    "mlb" -> MesenOutputFormat,
+    "mesen" -> MesenOutputFormat,
+    "asm6f" -> MesenOutputFormat,
+    "ld65" -> Ld65OutputFormat,
+    "ca65" -> Ld65OutputFormat,
+    "cc65" -> Ld65OutputFormat,
+    "dbg" -> Ld65OutputFormat,
     "sym" -> SymDebugOutputFormat)
 }
 
 sealed trait DebugOutputFormat {
 
-  def formatAll(labels: Seq[(String, (Int, Int))], breakpoints: Seq[(Int, Int)]): String = {
+  def formatAll(b: BankLayoutInFile, labels: Seq[FormattableLabel], breakpoints: Seq[(Int, Int)]): String = {
-    val labelPart = labelsHeader + labels.map(formatLineTupled).mkString("\n") + "\n"
+    val labelPart = labelsHeader + labels.map(formatLine).mkString("\n") + "\n"
     if (breakpoints.isEmpty) {
       labelPart
     } else {
@@ -25,9 +39,7 @@ sealed trait DebugOutputFormat {
     }
   }
 
-  final def formatLineTupled(labelAndValue: (String, (Int, Int))): String = formatLine(labelAndValue._1, labelAndValue._2._1, labelAndValue._2._2)
+  def formatLine(label: FormattableLabel): String
-
-  def formatLine(label: String, bank: Int, value: Int): String
 
   final def formatBreakpointTupled(value: (Int, Int)): Seq[String] = formatBreakpoint(value._1, value._2).toSeq
 
@@ -45,10 +57,25 @@ sealed trait DebugOutputFormat {
   def breakpointsHeader: String = ""
 }
 
+object RawDebugOutputFormat extends DebugOutputFormat {
+  override def formatLine(label: FormattableLabel): String = {
+    f"${label.bankNumber}%02X:${label.startValue}%04X:${label.endValue.fold("")(_.formatted("%04X"))}%s:${label.category}%s:$label%s"
+  }
+
+  override def fileExtension(bank: Int): String = ".labels"
+
+  override def filePerBank: Boolean = false
+
+  override def addOutputExtension: Boolean = false
+
+  override def formatBreakpoint(bank: Int, value: Int): Option[String] =
+    Some(f"$bank%02X:$value%04X::b:<breakpoint@$value%04X>")
+}
+
 object ViceDebugOutputFormat extends DebugOutputFormat {
-  override def formatLine(label: String, bank: Int, value: Int): String = {
+  override def formatLine(label: FormattableLabel): String = {
-    val normalized = label.replace('$', '_').replace('.', '_')
+    val normalized = label.labelName.replace('$', '_').replace('.', '_')
-    s"al ${value.toHexString} .$normalized"
+    s"al ${label.startValue.toHexString} .$normalized"
   }
 
   override def fileExtension(bank: Int): String = ".lbl"
@@ -61,8 +88,8 @@ object ViceDebugOutputFormat extends DebugOutputFormat {
 }
 
 object NesasmDebugOutputFormat extends DebugOutputFormat {
-  override def formatLine(label: String, bank: Int, value: Int): String = {
+  override def formatLine(label: FormattableLabel): String = {
-    label + " = $" + value.toHexString
+    label.labelName + " = $" + label.startValue.toHexString
   }
 
   override def fileExtension(bank: Int): String = ".fns"
@@ -75,8 +102,8 @@ object NesasmDebugOutputFormat extends DebugOutputFormat {
 }
 
 object SymDebugOutputFormat extends DebugOutputFormat {
-  override def formatLine(label: String, bank: Int, value: Int): String = {
+  override def formatLine(label: FormattableLabel): String = {
-    f"$bank%02x:$value%04x $label%s"
+    f"${label.bankNumber}%02x:${label.startValue}%04x ${label.labelName}%s"
   }
 
   override def fileExtension(bank: Int): String = ".sym"
@@ -93,8 +120,8 @@ object SymDebugOutputFormat extends DebugOutputFormat {
 }
 
 object FceuxDebugOutputFormat extends DebugOutputFormat {
-  override def formatLine(label: String, bank: Int, value: Int): String = {
+  override def formatLine(label: FormattableLabel): String = {
-    f"$$$value%04x#$label%s#"
+    f"$$${label.startValue}%04x#${label.labelName}%s#"
   }
 
   override def fileExtension(bank: Int): String = if (bank == 0xff) ".ram.nl" else s".$bank.nl"
@@ -105,3 +132,97 @@ object FceuxDebugOutputFormat extends DebugOutputFormat {
 
   override def formatBreakpoint(bank: Int, value: Int): Option[String] = None
 }
+
+object MesenOutputFormat extends DebugOutputFormat {
+
+  override def formatAll(b: BankLayoutInFile, labels: Seq[FormattableLabel], breakpoints: Seq[(Int, Int)]): String = {
+    val allStarts = labels.groupBy(_.bankName).mapValues(_.map(_.startValue).toSet)
+    labels.flatMap{ l =>
+      val mesenShift = b.getMesenShift(l.bankName)
+      val shiftedStart = l.startValue + mesenShift
+      var shiftedEnd = l.endValue.map(_ + mesenShift).filter(_ != shiftedStart)
+      l.endValue match {
+        case None =>
+        case Some(e) =>
+          // Mesen does not like labels of form XXX-XXX, where both ends are equal
+          breakable {
+            for (i <- l.startValue.+(1) to e) {
+              if (allStarts.getOrElse(l.bankName, Set.empty).contains(i)) {
+                shiftedEnd = None
+                break
+              }
+            }
+          }
+      }
+      if (shiftedStart >= 0 && shiftedEnd.forall(_ >= 0)) {
+        val normalized = l.labelName.replace('$', '_').replace('.', '_')
+        val comment = (l.category match {
+          case 'F' => "function "
+          case 'A' => "initialized array "
+          case 'V' => "initialized variable "
+          case 'a' => "array "
+          case 'v' => "variable "
+          case _ => ""
+        }) + l.labelName
+        Some(f"${l.mesenSymbol}%s:${shiftedStart}%04X${shiftedEnd.fold("")(e => f"-$e%04X")}%s:$normalized%s:$comment%s")
+      } else {
+        None
+      }
+    }.mkString("\n")
+  }
+
+  override def formatLine(label: FormattableLabel): String = throw new UnsupportedOperationException()
+
+  override def formatBreakpoint(bank: Int, value: Int): Option[String] = None
+
+  override def fileExtension(bank: Int): String = ".mlb"
+
+  override def filePerBank: Boolean = false
+
+  override def addOutputExtension: Boolean = false
+}
+
+object Ld65OutputFormat extends DebugOutputFormat {
+  override def formatLine(label: FormattableLabel): String = throw new UnsupportedOperationException()
+
+  override def formatBreakpoint(bank: Int, value: Int): Option[String] = None
+
+  override def fileExtension(bank: Int): String = ".dbg"
+
+  override def filePerBank: Boolean = false
+
+  override def addOutputExtension: Boolean = true
+
+  override def formatAll(b: BankLayoutInFile, labels: Seq[FormattableLabel], breakpoints: Seq[(Int, Int)]): String = {
+    val q = '"'
+    val allBanksInFile = b.allBanks()
+    val allBanks = (labels.map(_.bankName).distinct ++ allBanksInFile).distinct
+    val result = mutable.ListBuffer[String]()
+    result += "version\tmajor=2,minor=0"
+    result += s"info\tcsym=0,file=0,lib=0,line=0,mod=0,scope=1,seg=${allBanks.size},span=0,sym=${labels.size},type=4"
+    for ((bank, ix) <- allBanks.zipWithIndex) {
+      val common =  s"seg\tid=${ix},name=$q${bank}$q,start=0x${b.getStart(bank).toHexString},size=0x0,addrsize=absolute"
+      if (allBanksInFile.contains(bank)) {
+        result += common + s",ooffs=${b.ld65Offset(bank)}"
+      } else {
+        result += common
+      }
+    }
+    result += "scope\tid=0,name=\"\""
+    for ((label, ix) <- labels.sortBy(l => (l.bankName, l.startValue, l.labelName)).zipWithIndex) {
+      val name = label.labelName.replace('$', '@').replace('.', '@')
+      val sb = new StringBuilder
+      sb ++= s"sym\tid=${ix},name=$q${name}$q,addrsize=absolute,"
+      label.endValue match {
+        case Some(e) =>
+          if (!labels.exists(l => l.ne(label) && l.startValue >= label.startValue && l.startValue <= e)) {
+            sb ++= s"size=${ e - label.startValue + 1 },"
+          }
+        case None =>
+      }
+      sb ++= s"scope=0,val=0x${label.startValue.toHexString},seg=${allBanks.indexOf(label.bankName)},type=lab"
+      result += sb.toString
+    }
+    result.mkString("\n")
+  }
+}

src/main/scala/millfork/Main.scala

@@ -119,25 +119,35 @@ object Main {
         else if (l.startsWith("__")) 7
         else 0
       }
-      val sortedLabels = result.labels.groupBy(_._2).values.map(_.minBy(a => labelUnimportance(a._1) -> a._1)).toSeq.sortBy(_._2)
+      val sortedLabels: Seq[FormattableLabel] =
+        result.labels.groupBy(_._2).values
+          .map(_.minBy(a => labelUnimportance(a._1) -> a._1)).toSeq.sortBy(_._2)
+          .map { case (l, (b, s)) =>
+            val bankNumber = options.platform.bankNumbers.getOrElse(b, 0)
+            val mesenCategory = options.platform.getMesenLabelCategory(b, s)
+            result.endLabels.get(l) match {
+              case Some((c, e)) => FormattableLabel(l, b, bankNumber, s, Some(e), c, mesenCategory)
+              case _ => FormattableLabel(l, b, bankNumber,  s, None, 'x', mesenCategory)
+            }
+          }
       val sortedBreakpoints = result.breakpoints
       val format = c.outputLabelsFormatOverride.getOrElse(platform.outputLabelsFormat)
       val basename = if (format.addOutputExtension)  output + platform.fileExtension else output
       if (format.filePerBank) {
-        val banks = sortedLabels.map(_._2._1).toSet ++ sortedBreakpoints.map(_._2).toSet
+        val banks: Set[Int] = sortedLabels.map(_.bankNumber).toSet ++ sortedBreakpoints.map(_._1).toSet
         banks.foreach{ bank =>
-          val labels = sortedLabels.filter(_._2._1.==(bank))
+          val labels = sortedLabels.filter(_.bankNumber.==(bank))
           val breakpoints = sortedBreakpoints.filter(_._1.==(bank))
           val labelOutput = basename + format.fileExtension(bank)
           val path = Paths.get(labelOutput)
           errorReporting.debug("Writing labels to " + path.toAbsolutePath)
-          Files.write(path, format.formatAll(labels, breakpoints).getBytes(StandardCharsets.UTF_8))
+          Files.write(path, format.formatAll(result.bankLayoutInFile, labels, breakpoints).getBytes(StandardCharsets.UTF_8))
         }
       } else {
         val labelOutput = basename + format.fileExtension(0)
         val path = Paths.get(labelOutput)
         errorReporting.debug("Writing labels to " + path.toAbsolutePath)
-        Files.write(path, format.formatAll(sortedLabels, sortedBreakpoints).getBytes(StandardCharsets.UTF_8))
+        Files.write(path, format.formatAll(result.bankLayoutInFile, sortedLabels, sortedBreakpoints).getBytes(StandardCharsets.UTF_8))
       }
     }
     val defaultPrgOutput = if (output.endsWith(platform.fileExtension)) output else output + platform.fileExtension
@@ -165,7 +175,7 @@ object Main {
             f"${path.getFileName}%s ${start}%04X ${start}%04X ${codeLength}%04X".getBytes(StandardCharsets.UTF_8))
         }
     }
-    errorReporting.debug(s"Total time: ${Math.round((System.nanoTime() - startTime)/1e6)} ms")
+    errorReporting.info(s"Total time: ${Math.round((System.nanoTime() - startTime)/1e6)} ms")
     c.runFileName.foreach{ program =>
       if (File.separatorChar == '\\') {
         if (!new File(program).exists() && !new File(program + ".exe").exists()) {
@@ -241,10 +251,10 @@ object Main {
           log.debug(s"Failed to find the default include path: $err")
         case Right(path) =>
           log.debug(s"Automatically detected include path: $path")
-          return c.copy(includePath = List(path) ++ c.extraIncludePath)
+          return c.copy(includePath = List(System.getProperty("user.dir"), path) ++ c.extraIncludePath)
       }
     }
-    c.copy(includePath = c.includePath ++ c.extraIncludePath)
+    c.copy(includePath = System.getProperty("user.dir") :: (c.includePath ++ c.extraIncludePath))
   }
 
   private def assembleForMos(c: Context, platform: Platform, options: CompilationOptions): AssemblerOutput = {
@@ -283,6 +293,7 @@ object Main {
           if (options.flag(CompilationFlag.EmitHudsonOpcodes)) HudsonOptimizations.All else Nil,
           if (options.flag(CompilationFlag.EmitEmulation65816Opcodes)) SixteenOptimizations.AllForEmulation else Nil,
           if (options.flag(CompilationFlag.EmitNative65816Opcodes)) SixteenOptimizations.AllForNative else Nil,
+          if (options.flag(CompilationFlag.IdentityPage)) IdentityPageOptimizations.All else Nil,
           if (options.flag(CompilationFlag.DangerousOptimizations)) DangerousOptimizations.All else Nil
         ).flatten
         val goodCycle = List.fill(optLevel - 2)(OptimizationPresets.Good ++ goodExtras).flatten
@@ -321,7 +332,9 @@ object Main {
     val assemblyOptimizations = optLevel match {
       case 0 => Nil
       case _ =>
-        if (options.flag(CompilationFlag.EmitZ80Opcodes))
+        if (options.flag(CompilationFlag.EmitR800Opcodes))
+          Z80OptimizationPresets.GoodForR800
+        else if (options.flag(CompilationFlag.EmitZ80Opcodes))
           Z80OptimizationPresets.GoodForZ80
         else if (options.flag(CompilationFlag.EmitIntel8080Opcodes))
           Z80OptimizationPresets.GoodForIntel8080
@@ -427,7 +440,7 @@ object Main {
         p.toLowerCase(Locale.ROOT),
         errorReporting.fatal("Invalid label file format: " + p))
       c.copy(outputLabels = true, outputLabelsFormatOverride = Some(f))
-    }.description("Generate also the label file in the given format. Available options: vice, nesasm, sym.")
+    }.description("Generate also the label file in the given format. Available options: vice, nesasm, sym, raw.")
 
     boolean("-fbreakpoints", "-fno-breakpoints").action((c,v) =>
       c.changeFlag(CompilationFlag.EnableBreakpoints, v)
@@ -487,7 +500,7 @@ object Main {
       } else {
         errorReporting.fatal("Invalid syntax for -D option")
       }
-    }.description("Define a feature value for the preprocessor.")
+    }.description("Define a feature value for the preprocessor.").maxCount(Integer.MAX_VALUE)
 
     boolean("-finput_intel_syntax", "-finput_zilog_syntax").repeatable().action((c,v) =>
       c.changeFlag(CompilationFlag.UseIntelSyntaxForInput, v)
@@ -650,7 +663,7 @@ object Main {
       c.changeFlag(CompilationFlag.CompactReturnDispatchParams, v)
     }.description("Whether parameter values in return dispatch statements may overlap other objects. Enabled by default.")
     boolean("-fbounds-checking", "-fno-bounds-checking").action { (c, v) =>
-      c.changeFlag(CompilationFlag.VariableOverlap, v)
+      c.changeFlag(CompilationFlag.CheckIndexOutOfBounds, v)
     }.description("Whether should insert bounds checking on array access.")
     boolean("-flenient-encoding", "-fno-lenient-encoding").action { (c, v) =>
       c.changeFlag(CompilationFlag.LenientTextEncoding, v)
@@ -712,6 +725,9 @@ object Main {
       }.description("Optimize code even more.")
       if (i == 1 || i > 4) f.hidden()
     }
+    boolean("-fhints", "-fnohints").action{ (c,v) =>
+      c.changeFlag(CompilationFlag.UseOptimizationHints, v)
+    }.description("Whether optimization hints should be used.")
     flag("--inline").repeatable().action { c =>
       c.changeFlag(CompilationFlag.InlineFunctions, true)
     }.description("Inline functions automatically.").hidden()
@@ -742,6 +758,9 @@ object Main {
     boolean("-fregister-variables", "-fno-register-variables").action { (c, v) =>
       c.changeFlag(CompilationFlag.RegisterVariables, v)
     }.description("Allow moving local variables into CPU registers. Enabled by default.")
+    boolean("-fidentity-page", "-fno-identity-page").action { (c, v) =>
+      c.changeFlag(CompilationFlag.IdentityPage, v)
+    }.description("Whether should use an identity page to optimize certain operations.")
     flag("-Os", "--size").repeatable().action { c =>
       c.changeFlag(CompilationFlag.OptimizeForSize, true).
         changeFlag(CompilationFlag.OptimizeForSpeed, false).
@@ -754,6 +773,7 @@ object Main {
     }.description("Prefer faster code even if it is slightly bigger (experimental). Implies -finline.")
     flag("-Ob", "--blast-processing").repeatable().action { c =>
       c.changeFlag(CompilationFlag.OptimizeForSize, false).
+        changeFlag(CompilationFlag.IdentityPage, true).
         changeFlag(CompilationFlag.OptimizeForSpeed, true).
         changeFlag(CompilationFlag.OptimizeForSonicSpeed, true)
     }.description("Prefer faster code even if it is much bigger (experimental). Implies -finline.")
@@ -791,6 +811,10 @@ object Main {
       c.changeFlag(CompilationFlag.DeprecationWarning, v)
     }.description("Whether should warn about deprecated aliases. Default: enabled.")
 
+    boolean("-Wcomparisons", "-Wno-comparisons").repeatable().action { (c, v) =>
+      c.changeFlag(CompilationFlag.BytePointerComparisonWarning, v)
+    }.description("Whether should warn about comparisons between bytes and pointers. Default: enabled.")
+
     boolean("-Wextra-comparisons", "-Wno-extra-comparisons").repeatable().action { (c, v) =>
       c.changeFlag(CompilationFlag.ExtraComparisonWarnings, v)
     }.description("Whether should warn about simplifiable unsigned integer comparisons. Default: disabled.")
@@ -811,10 +835,18 @@ object Main {
       c.changeFlag(CompilationFlag.RorWarning, v)
     }.description("Whether should warn about the ROR instruction (6502 only). Default: disabled.")
 
+    boolean("-Woverflow", "-Wno-overflow").repeatable().action { (c, v) =>
+      c.changeFlag(CompilationFlag.ByteOverflowWarning, v)
+    }.description("Whether should warn about byte overflow. Default: enabled.")
+
     boolean("-Wuseless", "-Wno-useless").repeatable().action { (c, v) =>
       c.changeFlag(CompilationFlag.UselessCodeWarning, v)
     }.description("Whether should warn about code that does nothing. Default: enabled.")
 
+    boolean("-Whints", "-Wno-hints").repeatable().action { (c, v) =>
+      c.changeFlag(CompilationFlag.UnsupportedOptimizationHintWarning, v)
+    }.description("Whether should warn about unsupported optimization hints. Default: enabled.")
+
     fluff("", "Other options:", "")
 
     expansion("-Xd")("-O1", "-s", "-fsource-in-asm", "-g").description("Do a debug build. Equivalent to -O1 -s -fsource-in-asm -g")

src/main/scala/millfork/Platform.scala

@@ -42,6 +42,7 @@ class Platform(
                 val outputLabelsFormat: DebugOutputFormat,
                 val outputStyle: OutputStyle.Value
               ) {
+
   def hasZeroPage: Boolean = cpuFamily == CpuFamily.M6502
 
   def cpuFamily: CpuFamily.Value = CpuFamily.forType(this.cpu)
@@ -60,6 +61,18 @@ class Platform(
     val e2 = bankEndBefore(bank2)
     e2 > s1 && s2 < e1
   }
+
+  lazy val banksExplicitlyWrittenToOutput: Set[String] = bankNumbers.keySet.filter(b => defaultOutputPackager.writes(b)).toSet
+
+  def getMesenLabelCategory(bank: String, address: Int): Char = {
+    // see: https://www.mesen.ca/docs/debugging/debuggerintegration.html#mesen-label-files-mlb
+    val start = bankStart(bank)
+    val end = bankEndBefore(bank)
+    if (start > address || address >= end) 'G'
+    else if (banksExplicitlyWrittenToOutput(bank)) 'P'
+    else if (bank == "default") 'R'
+    else 'W' // TODO: distinguish between W and S
+  }
 }
 
 object Platform {

src/main/scala/millfork/assembly/AssemblyOptimization.scala

@@ -2,7 +2,7 @@ package millfork.assembly
 
 import millfork.{CompilationFlag, CompilationOptions}
 import millfork.compiler.LabelGenerator
-import millfork.env.{NormalFunction, ThingInMemory}
+import millfork.env.{Constant, NormalFunction, ThingInMemory}
 import millfork.error.Logger
 import millfork.node.NiceFunctionProperty
 
@@ -10,8 +10,9 @@ import millfork.node.NiceFunctionProperty
   * @author Karol Stasiak
   */
 case class OptimizationContext(options: CompilationOptions,
-                               labelMap: Map[String, (Int, Int)],
+                               labelMap: Map[String, (String, Int)],
                                zreg: Option[ThingInMemory],
+                               identityPage: Constant,
                                niceFunctionProperties: Set[(NiceFunctionProperty, String)]) {
   @inline
   def log: Logger = options.log
@@ -25,4 +26,6 @@ trait AssemblyOptimization[T <: AbstractCode] {
   def optimize(f: NormalFunction, code: List[T], context: OptimizationContext): List[T]
 
   def requiredFlags: Set[CompilationFlag.Value] = Set.empty
+
+  def minimumRequiredLines: Int
 }

src/main/scala/millfork/assembly/m6809/MLine.scala

@@ -168,6 +168,7 @@ case class MLine(opcode: MOpcode.Value, addrMode: MAddrMode, parameter: Constant
 
   def changesRegister(reg: M6809Register.Value): Boolean = {
     import M6809Register._
+    if (MOpcode.NotActualOpcodes(opcode)) return false
     def overlaps(other: M6809Register.Value): Boolean = {
       if (reg == D && (other == A || other == B))  true
       else if (other == D && (reg == A || reg == B))  true
@@ -202,12 +203,13 @@ case class MLine(opcode: MOpcode.Value, addrMode: MAddrMode, parameter: Constant
     }
   }
 
-  def changesCarryFlag: Boolean = !MOpcode.PreservesC(opcode)
+  def changesCarryFlag: Boolean = !MOpcode.NotActualOpcodes(opcode) && !MOpcode.PreservesC(opcode)
 
 
 
   def readsRegister(reg: M6809Register.Value): Boolean = {
     import M6809Register._
+    if (MOpcode.NotActualOpcodes(opcode)) return false
     def overlaps(other: M6809Register.Value): Boolean = {
       if (reg == D && (other == A || other == B))  true
       else if (other == D && (reg == A || reg == B))  true
@@ -252,15 +254,17 @@ case class MLine(opcode: MOpcode.Value, addrMode: MAddrMode, parameter: Constant
       case MUL => overlaps(D)
       case ABX => reg == X || overlaps(B)
       case NOP | SWI | SWI2 | SWI3 | SYNC => false
+      case LDB | LDA | LDX | LDY | LDU => false
       case INC | DEC | ROL | ROR | ASL | ASR | LSR | CLR | COM | NEG | TST => false // variants for A and B handled before
       case op if Branching(op) => false
-      case JMP => false
+      case JMP | RTS => false
       case _ => true // TODO
     }
   }
 
   def readsMemory(): Boolean = {
     import MOpcode._
+    if (MOpcode.NotActualOpcodes(opcode)) return false
     val opcodeIsForReading = opcode match {
       case LDA | LDB | LDD | LDX | LDY | LDU | LDS | PULU | PULS => true
       case ADDA | SUBA | ADCA | SBCA | ORA | EORA | ANDA | CMPA | BITA => true
@@ -289,6 +293,7 @@ case class MLine(opcode: MOpcode.Value, addrMode: MAddrMode, parameter: Constant
 
   def changesMemory(): Boolean = {
     import MOpcode._
+    if (NotActualOpcodes(opcode)) return false
     val opcodeIsForWriting = opcode match {
       case LDA | LDB | LDD | LDX | LDY | LDU | LDS | PULU | PULS => false
       case ADDA | SUBA | ADCA | SBCA | ORA | EORA | ANDA | CMPA | BITA => false

src/main/scala/millfork/assembly/m6809/MOpcode.scala

@@ -32,9 +32,10 @@ object MOpcode extends Enumeration {
   TFR, TST,
   DISCARD_D, DISCARD_X, DISCARD_Y, DISCARD_CC, CHANGED_MEM, BYTE, LABEL = Value
 
+  val NotActualOpcodes: Set[MOpcode.Value] = Set(DISCARD_D, DISCARD_X, DISCARD_Y, DISCARD_CC, CHANGED_MEM, BYTE, LABEL)
+
   private val toMap: Map[String, MOpcode.Value] = {
-    val notActualOpcodes: Set[MOpcode.Value] = Set(DISCARD_D, DISCARD_X, DISCARD_Y, DISCARD_CC, CHANGED_MEM, BYTE, LABEL)
+    values.filterNot(NotActualOpcodes).map(o => o.toString -> o).toMap ++ Map("BHS" -> BCC, "BLO" -> BCS, "LSL" -> ASL)
-    values.filterNot(notActualOpcodes).map(o => o.toString -> o).toMap ++ Map("BHS" -> BCC, "BLO" -> BCS, "LSL" -> ASL)
   }
   val NoopDiscard: Set[MOpcode.Value] = Set(DISCARD_D, DISCARD_X, DISCARD_Y, DISCARD_CC)
   val PrefixedBy10: Set[MOpcode.Value] = Set(CMPD, CMPY, LDS, LDY, SWI2, STS, STY) // TODO: branches

src/main/scala/millfork/assembly/m6809/opt/AlwaysGoodMOptimizations.scala

@@ -3,7 +3,8 @@ package millfork.assembly.m6809.opt
 
 import millfork.assembly.AssemblyOptimization
 import millfork.assembly.m6809.MOpcode._
-import millfork.assembly.m6809.{Absolute, DAccumulatorIndexed, Immediate, LongRelative, MAddrMode, MLine, MState, PostIncremented, RegisterSet}
+import millfork.assembly.m6809.{Absolute, DAccumulatorIndexed, Immediate, Indexed, InherentA, InherentB, LongRelative, MAddrMode, MLine, MState, PostIncremented, RegisterSet}
+import millfork.env.{CompoundConstant, Constant, MathOperator}
 import millfork.node.M6809Register
 
 /**
@@ -19,15 +20,38 @@ object AlwaysGoodMOptimizations {
     (Elidable & HasOpcodeIn(LDX, LEAX) & DoesntMatterWhatItDoesWith(MState.X, MState.NF, MState.ZF, MState.VF)) ~~> (_ => Nil),
     (Elidable & HasOpcodeIn(LDY, LEAY) & DoesntMatterWhatItDoesWith(MState.Y, MState.NF, MState.ZF, MState.VF)) ~~> (_ => Nil),
     (Elidable & HasOpcode(STB) & MatchAddrMode(0) & MatchParameter(1)) ~
-      (Linear & Not(ChangesB) & DoesntChangeIndexingInAddrMode(0)).* ~
+      (Linear & Not(ChangesB) & DoesntChangeIndexingInAddrMode(0) & DoesntChangeMemoryAt(0, 1)).* ~
       (Elidable & HasOpcode(LDB) & MatchAddrMode(0) & MatchParameter(1)
         & DoesntMatterWhatItDoesWith(MState.NF, MState.ZF, MState.VF)) ~~> (_.init),
     (Elidable & HasOpcode(STD) & MatchAddrMode(0) & MatchParameter(1)) ~
-      (Linear & Not(ChangesB) & DoesntChangeIndexingInAddrMode(0)).* ~
+      (Linear & Not(ChangesB) & Not(ChangesA) & DoesntChangeIndexingInAddrMode(0) & DoesntChangeMemoryAt(0, 1)).* ~
       (Elidable & HasOpcode(LDD) & MatchAddrMode(0) & MatchParameter(1)
         & DoesntMatterWhatItDoesWith(MState.NF, MState.ZF, MState.VF)) ~~> (_.init),
   )
 
+  val PointlessCompare = new RuleBasedAssemblyOptimization("Pointless compare",
+    needsFlowInfo = FlowInfoRequirement.BackwardFlow,
+    (HasOpcodeIn(LDA, ANDA, ORA, EORA, ADDA, ADCA, SUBA, SBCA)) ~
+      (Elidable & HasOpcode(CMPA) & HasImmediate(0) & DoesntMatterWhatItDoesWith(MState.VF, MState.CF, MState.HF))  ~~> {code => code.init},
+    (HasOpcodeIn(LDB, ANDB, ORB, EORB, ADDB, ADCB, SUBB, SBCB)) ~
+      (Elidable & HasOpcode(CMPB) & HasImmediate(0) & DoesntMatterWhatItDoesWith(MState.VF, MState.CF, MState.HF)) ~~> {code => code.init},
+
+    (Elidable & HasOpcode(EORA) & HasAddrMode(Immediate) & MatchParameter(0)) ~
+      (Elidable & HasOpcode(CMPA) & HasAddrMode(Immediate) & MatchParameter(1)
+        & DoesntMatterWhatItDoesWith(MState.A, MState.NF, MState.VF, MState.CF, MState.HF)) ~~> { (code, ctx) =>
+      val c0 = ctx.get[Constant](0)
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = CompoundConstant(MathOperator.Exor, c0, c1).quickSimplify))
+    },
+    (Elidable & HasOpcode(EORB) & HasAddrMode(Immediate) & MatchParameter(0)) ~
+      (Elidable & HasOpcode(CMPB) & HasAddrMode(Immediate) & MatchParameter(1)
+        & DoesntMatterWhatItDoesWith(MState.B, MState.NF, MState.VF, MState.CF, MState.HF)) ~~> { (code, ctx) =>
+      val c0 = ctx.get[Constant](0)
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = CompoundConstant(MathOperator.Exor, c0, c1).quickSimplify))
+    },
+  )
+
   val SimplifiableZeroStore = new RuleBasedAssemblyOptimization("Simplifiable zero store",
     needsFlowInfo = FlowInfoRequirement.BothFlows,
     (Elidable & HasOpcode(LDA) & HasImmediate(0) & DoesntMatterWhatItDoesWith(MState.CF)) ~~> {
@@ -50,6 +74,75 @@ object AlwaysGoodMOptimizations {
     },
   )
 
+  val SimplifiableComparison = new RuleBasedAssemblyOptimization("Simplifiable comparison",
+    needsFlowInfo = FlowInfoRequirement.BothFlows,
+
+    (Elidable & HasOpcode(EORB) & HasAddrMode(Immediate) & MatchParameter(0)) ~
+      (Elidable & HasOpcode(CMPB) & HasAddrMode(Immediate) & MatchParameter(1)
+        & DoesntMatterWhatItDoesWith(MState.CF, MState.B, MState.VF, MState.HF)) ~~> { (code, ctx) =>
+      val c0 = ctx.get[Constant](0)
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = CompoundConstant(MathOperator.Exor, c0, c1).quickSimplify))
+    },
+    (Elidable & HasOpcode(ADDB) & HasImmediate(1)) ~
+      (Elidable & HasOpcode(CMPB) & HasAddrMode(Immediate) & MatchParameter(1)
+        & DoesntMatterWhatItDoesWith(MState.CF, MState.B, MState.VF, MState.HF)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 - 1).quickSimplify))
+    },
+    (Elidable & HasOpcode(SUBB) & HasImmediate(1)) ~
+      (Elidable & HasOpcode(CMPB) & HasAddrMode(Immediate) & MatchParameter(1)
+        & DoesntMatterWhatItDoesWith(MState.CF, MState.B, MState.VF, MState.HF)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 + 1).quickSimplify))
+    },
+    (Elidable & HasOpcode(INC) & HasAddrMode(InherentB)) ~
+      (Elidable & HasOpcode(CMPB) & HasAddrMode(Immediate) & MatchParameter(1)
+        & DoesntMatterWhatItDoesWith(MState.CF, MState.B, MState.VF, MState.HF)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 - 1).quickSimplify))
+    },
+    (Elidable & HasOpcode(DEC) & HasAddrMode(InherentB)) ~
+      (Elidable & HasOpcode(CMPB) & HasAddrMode(Immediate) & MatchParameter(1)
+        & DoesntMatterWhatItDoesWith(MState.CF, MState.B, MState.VF, MState.HF)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 + 1).quickSimplify))
+    },
+
+    (Elidable & HasOpcode(EORA) & HasAddrMode(Immediate) & MatchParameter(0)) ~
+      (Elidable & HasOpcode(CMPA) & HasAddrMode(Immediate) & MatchParameter(1)
+        & DoesntMatterWhatItDoesWith(MState.CF, MState.A, MState.VF, MState.HF)) ~~> { (code, ctx) =>
+      val c0 = ctx.get[Constant](0)
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = CompoundConstant(MathOperator.Exor, c0, c1).quickSimplify))
+    },
+    (Elidable & HasOpcode(ADDA) & HasImmediate(1)) ~
+      (Elidable & HasOpcode(CMPA) & HasAddrMode(Immediate) & MatchParameter(1)
+        & DoesntMatterWhatItDoesWith(MState.CF, MState.A, MState.VF, MState.HF)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 - 1).quickSimplify))
+    },
+    (Elidable & HasOpcode(SUBA) & HasImmediate(1)) ~
+      (Elidable & HasOpcode(CMPA) & HasAddrMode(Immediate) & MatchParameter(1)
+        & DoesntMatterWhatItDoesWith(MState.CF, MState.A, MState.VF, MState.HF)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 + 1).quickSimplify))
+    },
+    (Elidable & HasOpcode(INC) & HasAddrMode(InherentA)) ~
+      (Elidable & HasOpcode(CMPA) & HasAddrMode(Immediate) & MatchParameter(1)
+        & DoesntMatterWhatItDoesWith(MState.CF, MState.A, MState.VF, MState.HF)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 - 1).quickSimplify))
+    },
+    (Elidable & HasOpcode(DEC) & HasAddrMode(InherentA)) ~
+      (Elidable & HasOpcode(CMPA) & HasAddrMode(Immediate) & MatchParameter(1)
+        & DoesntMatterWhatItDoesWith(MState.CF, MState.A, MState.VF, MState.HF)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 + 1).quickSimplify))
+    },
+
+  )
+
   val PointlessRegisterTransfers = new RuleBasedAssemblyOptimization("Pointless register transfers",
     needsFlowInfo = FlowInfoRequirement.BackwardFlow,
     (Elidable & IsTfr(M6809Register.D, M6809Register.X)) ~
@@ -144,14 +237,67 @@ object AlwaysGoodMOptimizations {
       (_.map(_.copy(opcode = LDD))),
     (Elidable & HasImmediate(0) & HasOpcodeIn(ORB, EORB, ADDB, ORA, EORA, ADDA, ADDD) & DoesntMatterWhatItDoesWith(MState.VF, MState.ZF, MState.NF, MState.CF, MState.HF)) ~~>
       (_ => Nil),
+    (HasOpcode(LDB)) ~
+      (Elidable & HasOpcode(ANDB) & HasAddrMode(Immediate) & MatchParameter(0)) ~
+      (Elidable & HasOpcode(BNE) & MatchParameter(1)) ~
+      (Elidable & HasOpcode(LDB)) ~
+      (HasOpcode(ANDB) & HasAddrMode(Immediate) & MatchParameter(0)) ~
+      (HasOpcode(BEQ)) ~
+      (HasOpcode(LABEL) & MatchParameter(1)) ~~> { code =>
+      List(code.head, code(3).copy(opcode = ORB)) ++ code.drop(4)
+    },
+    (Elidable & HasOpcode(ADDB) & HasImmediate(1) & DoesntMatterWhatItDoesWith(MState.VF, MState.CF, MState.HF)) ~~> { code => List(MLine.inherentB(INC)) },
+    (Elidable & HasOpcode(ADDA) & HasImmediate(1) & DoesntMatterWhatItDoesWith(MState.VF, MState.CF, MState.HF)) ~~> { code => List(MLine.inherentA(INC)) },
+    (Elidable & HasOpcode(SUBB) & HasImmediate(1) & DoesntMatterWhatItDoesWith(MState.VF, MState.CF, MState.HF)) ~~> { code => List(MLine.inherentB(DEC)) },
+    (Elidable & HasOpcode(SUBA) & HasImmediate(1) & DoesntMatterWhatItDoesWith(MState.VF, MState.CF, MState.HF)) ~~> { code => List(MLine.inherentA(DEC)) },
 
   )
 
+  val SimplifiableAddressing = new RuleBasedAssemblyOptimization("Simplifiable addressing",
+    needsFlowInfo = FlowInfoRequirement.ForwardFlow,
+    (NotFixed & MatchX(0) & HasAddrMode(Indexed(M6809Register.X, indirect = false)) & Not(HasOpcodeIn(LEAX, LEAY, LEAS, LEAU))) ~~> { (code, ctx) =>
+      val x = ctx.get[Constant](0)
+      code.map(l => l.copy(addrMode = Absolute(indirect = false), parameter = (x + l.parameter).quickSimplify))
+    },
+    (NotFixed & MatchY(0) & HasAddrMode(Indexed(M6809Register.Y, indirect = false)) & Not(HasOpcodeIn(LEAX, LEAY, LEAS, LEAU))) ~~> { (code, ctx) =>
+      val y = ctx.get[Constant](0)
+      code.map(l => l.copy(addrMode = Absolute(indirect = false), parameter = (y + l.parameter).quickSimplify))
+    },
+    (NotFixed & MatchX(0) & HasAddrMode(Indexed(M6809Register.X, indirect = false)) & HasOpcodeIn(LEAX, LEAY, LEAS, LEAU)) ~~> { (code, ctx) =>
+      val x = ctx.get[Constant](0)
+      code.map(l => l.copy(opcode = l.opcode match {
+        case LEAX => LDX
+        case LEAY => LDY
+        case LEAU => LDU
+        case LEAS => LDS
+      }, addrMode = Immediate, parameter = (x + l.parameter).quickSimplify))
+    },
+    (NotFixed & MatchY(0) & HasAddrMode(Indexed(M6809Register.X, indirect = false)) & HasOpcodeIn(LEAX, LEAY, LEAS, LEAU)) ~~> { (code, ctx) =>
+      val y = ctx.get[Constant](0)
+      code.map(l => l.copy(opcode = l.opcode match {
+        case LEAX => LDX
+        case LEAY => LDY
+        case LEAU => LDU
+        case LEAS => LDS
+      }, addrMode = Immediate, parameter = (y + l.parameter).quickSimplify))
+    },
+  )
+
+  val UnusedLabelRemoval = new RuleBasedAssemblyOptimization("Unused label removal",
+    needsFlowInfo = FlowInfoRequirement.JustLabels,
+    (Elidable & HasOpcode(LABEL) & HasCallerCount(0) & ParameterIsLocalLabel) ~~> (_ => Nil)
+  )
+
+
   val All: Seq[AssemblyOptimization[MLine]] = Seq(
     PointlessLoad,
+    PointlessCompare,
     PointlessRegisterTransfers,
+    SimplifiableAddressing,
     SimplifiableArithmetics,
+    SimplifiableComparison,
     SimplifiableJumps,
-    SimplifiableZeroStore
+    SimplifiableZeroStore,
+    UnusedLabelRemoval
   )
 }

src/main/scala/millfork/assembly/m6809/opt/CpuStatus.scala

@@ -35,6 +35,11 @@ case class CpuStatus(a: Status[Int] = UnknownStatus,
   def nzB(i: Long): CpuStatus =
     this.copy(n = SingleStatus((i & 0x80) != 0), z = SingleStatus((i & 0xff) == 0))
 
+  def nzB(i: Status[Int]): CpuStatus = i match {
+    case SingleStatus(j) => this.copy(n = SingleStatus((j & 0x80) != 0), z = SingleStatus((j & 0xff) == 0))
+    case _ => this.copy(n = AnyStatus, z = AnyStatus)
+  }
+
   def nzW(i: Long): CpuStatus =
     this.copy(n = SingleStatus((i & 0x8000) != 0), z = SingleStatus((i & 0xffff) == 0))
 
@@ -44,6 +49,11 @@ case class CpuStatus(a: Status[Int] = UnknownStatus,
     case _ => this.nz
   }
 
+  def nzW(i: Status[Int]): CpuStatus = i match {
+    case SingleStatus(j) => this.copy(n = SingleStatus((j & 0x8000) != 0), z = SingleStatus((j & 0xffff) == 0))
+    case _ => this.copy(n = AnyStatus, z = AnyStatus)
+  }
+
   def ~(that: CpuStatus) = new CpuStatus(
     a = this.a ~ that.a,
     b = this.b ~ that.b,

src/main/scala/millfork/assembly/m6809/opt/FlowAnalyzer.scala

@@ -52,7 +52,7 @@ object FlowAnalyzer {
     }
     val labelMap: () => Option[Map[String, Int]] = () => req match {
       case FlowInfoRequirement.NoRequirement => None
-      case _ => Some(code.flatMap(_.parameter.extractLabels).groupBy(identity).mapValues(_.size).view.force)
+      case _ => Some(code.filter(m => m.opcode != MOpcode.LABEL).flatMap(_.parameter.extractLabels).groupBy(identity).mapValues(_.size).view.force)
     }
     val holder = new FlowHolder(forwardFlow, reverseFlow)
     code.zipWithIndex.map{ case (line, i) => FlowInfo(holder, i, labelMap) -> line}

src/main/scala/millfork/assembly/m6809/opt/ForwardFlowAnalysis.scala

@@ -2,10 +2,11 @@ package millfork.assembly.m6809.opt
 
 import millfork.CompilationFlag
 import millfork.assembly.OptimizationContext
-import millfork.assembly.m6809.{Immediate, MLine, MLine0}
+import millfork.assembly.m6809.{Absolute, Immediate, Inherent, InherentA, InherentB, MLine, MLine0, TwoRegisters}
 import millfork.assembly.opt.Status.SingleFalse
 import millfork.assembly.opt.{AnyStatus, FlowCache, SingleStatus, Status}
 import millfork.env._
+import millfork.node.M6809NiceFunctionProperty.{DoesntChangeA, DoesntChangeB, DoesntChangeU, DoesntChangeX, DoesntChangeY}
 import millfork.node.{M6809Register, NiceFunctionProperty}
 
 import scala.util.control.Breaks._
@@ -62,33 +63,108 @@ object ForwardFlowAnalysis {
               case _ => None
             }).fold(currentStatus)(_ ~ _)
 
-          case MLine0(JSR, _, MemoryAddressConstant(th)) =>
+          case MLine0(JSR, am, MemoryAddressConstant(th)) =>
+            var prU = bpInU
+            var prY = bpInY
+            var prA = false
+            var prB = false
+            var prX = false
+            (am, th) match {
+              case (Absolute(false), fun: FunctionInMemory) =>
+                val nfp = optimizationContext.niceFunctionProperties
+                val fn = fun.name
+                if (nfp(DoesntChangeX -> fn)) prX = true
+                if (nfp(DoesntChangeY -> fn)) prY = true
+                if (nfp(DoesntChangeU -> fn)) prU = true
+                if (nfp(DoesntChangeA -> fn)) prA = true
+                if (nfp(DoesntChangeB -> fn)) prB = true
+              case _ =>
+            }
             currentStatus = initialStatus.copy(
               memStack = currentStatus.memStack,
-              u = if (bpInU) currentStatus.u else AnyStatus,
+              u = if (prU) currentStatus.u else AnyStatus,
-              y = if (bpInY) currentStatus.y else AnyStatus
+              x = if (prX) currentStatus.x else AnyStatus,
+              y = if (prY) currentStatus.y else AnyStatus,
+              a = if (prA) currentStatus.a else AnyStatus,
+              b = if (prB) currentStatus.b else AnyStatus
             )
 
           case MLine0(JSR | BYTE, _, _) =>
             currentStatus = initialStatus
 
-          case MLine0(NOP, _, _) =>
+          case MLine0(op, Immediate, constant) if ForwardFlowAnalysisForImmediate.hasDefinition(op) =>
-            ()
+            ForwardFlowAnalysisForImmediate.get(op)(constant, currentStatus)
+          case MLine0(op, Inherent, _) if ForwardFlowAnalysisForInherent.hasDefinition(op) =>
+            ForwardFlowAnalysisForInherent.get(op)(currentStatus)
+          case MLine0(op, InherentA, _) if ForwardFlowAnalysisForInherentA.hasDefinition(op) =>
+            ForwardFlowAnalysisForInherentA.get(op)(currentStatus)
+          case MLine0(op, InherentB, _) if ForwardFlowAnalysisForInherentB.hasDefinition(op) =>
+            ForwardFlowAnalysisForInherentB.get(op)(currentStatus)
 
-          case MLine0(LDA, Immediate, NumericConstant(n, _)) =>
+          case MLine0(LDA, _, _) =>
-            currentStatus = currentStatus.copy(a = SingleStatus(n.toInt & 0xff), v = SingleFalse).nzB(n)
+            currentStatus = currentStatus.copy(a = AnyStatus, n = AnyStatus, z = AnyStatus, v = SingleFalse)
-          case MLine0(LDB, Immediate, NumericConstant(n, _)) =>
+          case MLine0(LDB, _, _) =>
-            currentStatus = currentStatus.copy(b = SingleStatus(n.toInt & 0xff), v = SingleFalse).nzB(n)
+            currentStatus = currentStatus.copy(b = AnyStatus, n = AnyStatus, z = AnyStatus, v = SingleFalse)
-          case MLine0(LDD, Immediate, NumericConstant(n, _)) =>
+          case MLine0(LDD, _, _) =>
-            currentStatus = currentStatus.copy(
+            currentStatus = currentStatus.copy(a = AnyStatus, b = AnyStatus, n = AnyStatus, z = AnyStatus, v = SingleFalse)
-              a = SingleStatus(n.toInt.>>(8) & 0xff),
+          case MLine0(LDX, _, _) =>
-              b = SingleStatus(n.toInt & 0xff),
+            currentStatus = currentStatus.copy(x = AnyStatus, n = AnyStatus, z = AnyStatus, v = SingleFalse)
-              v = SingleFalse
+          case MLine0(LDY, _, _) =>
-            ).nzW(n)
+            currentStatus = currentStatus.copy(y = AnyStatus, n = AnyStatus, z = AnyStatus, v = SingleFalse)
-          case MLine0(LDX, Immediate, c) =>
+          case MLine0(STA | STB | STD | STX | STU | STY | STS, _, _) =>
-            currentStatus = currentStatus.copy(x = SingleStatus(c), v = SingleFalse).nzW(c)
+            // don't change
-          case MLine0(LDY, Immediate, c) =>
+          case MLine0(TFR, TwoRegisters(source, target), _) =>
-            currentStatus = currentStatus.copy(y = SingleStatus(c), v = SingleFalse).nzW(c)
+            import M6809Register._
+            (source, target) match {
+              case (A, B) => currentStatus = currentStatus.copy(b = currentStatus.a)
+              case (B, A) => currentStatus = currentStatus.copy(a = currentStatus.b)
+              case (CC, A) => currentStatus = currentStatus.copy(a = AnyStatus)
+              case (CC, B) => currentStatus = currentStatus.copy(b = AnyStatus)
+              case (A, CC) | (B, CC) => currentStatus = currentStatus.copy(c = AnyStatus, z = AnyStatus, n = AnyStatus, v = AnyStatus)
+              case (S, D) => currentStatus = currentStatus.copy(a = AnyStatus, b = AnyStatus)
+              case (S, X) => currentStatus = currentStatus.copy(x = AnyStatus)
+              case (S, Y) => currentStatus = currentStatus.copy(y = AnyStatus)
+              case (S, U) => currentStatus = currentStatus.copy(u = AnyStatus)
+              case (D, X) => currentStatus = currentStatus.copy(x = currentStatus.d.map(n => NumericConstant(n, 2)))
+              case (D, Y) => currentStatus = currentStatus.copy(y = currentStatus.d.map(n => NumericConstant(n, 2)))
+              case (D, U) => currentStatus = currentStatus.copy(u = currentStatus.d.map(n => NumericConstant(n, 2)))
+              case (X, Y) => currentStatus = currentStatus.copy(y = currentStatus.x)
+              case (X, U) => currentStatus = currentStatus.copy(u = currentStatus.x)
+              case (Y, X) => currentStatus = currentStatus.copy(x = currentStatus.y)
+              case (Y, U) => currentStatus = currentStatus.copy(u = currentStatus.y)
+              case (U, X) => currentStatus = currentStatus.copy(x = currentStatus.u)
+              case (U, Y) => currentStatus = currentStatus.copy(y = currentStatus.u)
+              case (X, D) =>
+                val (h, l) = currentStatus.x.toHiLo
+                currentStatus = currentStatus.copy(a = h, b = l)
+              case (Y, D) =>
+                val (h, l) = currentStatus.y.toHiLo
+                currentStatus = currentStatus.copy(a = h, b = l)
+              case (U, D) =>
+                val (h, l) = currentStatus.u.toHiLo
+                currentStatus = currentStatus.copy(a = h, b = l)
+              case _ => currentStatus = initialStatus
+            }
+          case MLine0(EXG, TwoRegisters(source, target), _) =>
+            import M6809Register._
+            (source, target) match {
+              case (A, B) | (B, A) => currentStatus = currentStatus.copy(a = currentStatus.b, b = currentStatus.a)
+              case (A, CC) | (CC, A) => currentStatus = currentStatus.copy(a = AnyStatus, c = AnyStatus, v = AnyStatus, n = AnyStatus, z = AnyStatus)
+              case (B, CC) | (CC, B) => currentStatus = currentStatus.copy(b = AnyStatus, c = AnyStatus, v = AnyStatus, n = AnyStatus, z = AnyStatus)
+              case (X, Y) | (Y, X) => currentStatus = currentStatus.copy(y = currentStatus.x, x = currentStatus.y)
+              case (U, Y) | (Y, U) => currentStatus = currentStatus.copy(y = currentStatus.u, u = currentStatus.y)
+              case (X, U) | (U, X) => currentStatus = currentStatus.copy(u = currentStatus.x, x = currentStatus.u)
+              case (X, D) | (D, X) =>
+                val (h, l) = currentStatus.x.toHiLo
+                currentStatus = currentStatus.copy(a = h, b = l, x = currentStatus.d.map(n => NumericConstant(n, 2)))
+              case (Y, D) | (D, Y) =>
+                val (h, l) = currentStatus.y.toHiLo
+                currentStatus = currentStatus.copy(a = h, b = l, y = currentStatus.d.map(n => NumericConstant(n, 2)))
+              case (U, D) | (D, U) =>
+                val (h, l) = currentStatus.u.toHiLo
+                currentStatus = currentStatus.copy(a = h, b = l, u = currentStatus.d.map(n => NumericConstant(n, 2)))
+              case _ => currentStatus = initialStatus
+            }
 
           case MLine0(opcode, addrMode, _) =>
             // TODO

src/main/scala/millfork/assembly/m6809/opt/ForwardFlowAnalysisForImmediate.scala

@@ -0,0 +1,80 @@
+package millfork.assembly.m6809.opt
+
+import millfork.assembly.m6809.MOpcode
+import millfork.assembly.m6809.MOpcode._
+import millfork.assembly.opt.{AnyStatus, SingleStatus, Status}
+import millfork.assembly.opt.Status.SingleFalse
+import millfork.env.Constant
+
+/**
+  * @author Karol Stasiak
+  */
+object ForwardFlowAnalysisForImmediate {
+  private val map: Map[MOpcode.Value, (Constant, CpuStatus) => CpuStatus] = Map(
+    LDX -> {(c, currentStatus) =>
+      currentStatus.copy(x = SingleStatus(c), v = SingleFalse).nzW(c)
+    },
+    LDY -> {(c, currentStatus) =>
+      currentStatus.copy(y = SingleStatus(c), v = SingleFalse).nzW(c)
+    },
+    LDU -> {(c, currentStatus) =>
+      currentStatus.copy(u = SingleStatus(c), v = SingleFalse).nzW(c)
+    },
+    LDA -> {(c, currentStatus) =>
+      val value = Status.fromByte(c)
+      currentStatus.copy(a = value, v = SingleFalse).nzB(value)
+    },
+    LDB -> {(c, currentStatus) =>
+      val value = Status.fromByte(c)
+      currentStatus.copy(a = value, v = SingleFalse).nzB(value)
+    },
+    LDD -> {(c, currentStatus) =>
+      val value = Status.fromByte(c)
+      currentStatus.copy(a = value.hi, b = value.lo, v = SingleFalse).nzW(value)
+    },
+    ORA -> { (c, currentStatus) =>
+      val newValue = (currentStatus.a <*> Status.fromByte(c)) { (x, y) => (x | y) & 0xff }
+      currentStatus.copy(a = newValue, v = SingleFalse).nzB(newValue)
+    },
+    ORB -> { (c, currentStatus) =>
+      val newValue = (currentStatus.b <*> Status.fromByte(c)) { (x, y) => (x | y) & 0xff }
+      currentStatus.copy(b = newValue, v = SingleFalse).nzB(newValue)
+    },
+    EORA -> { (c, currentStatus) =>
+      val newValue = (currentStatus.a <*> Status.fromByte(c)) { (x, y) => (x ^ y) & 0xff }
+      currentStatus.copy(a = newValue, v = SingleFalse).nzB(newValue)
+    },
+    EORB -> { (c, currentStatus) =>
+      val newValue = (currentStatus.b <*> Status.fromByte(c)) { (x, y) => (x ^ y) & 0xff }
+      currentStatus.copy(b = newValue, v = SingleFalse).nzB(newValue)
+    },
+    ANDA -> { (c, currentStatus) =>
+      val newValue = (currentStatus.a <*> Status.fromByte(c)) { (x, y) => (x & y) & 0xff }
+      currentStatus.copy(a = newValue, v = SingleFalse).nzB(newValue)
+    },
+    ANDB -> { (c, currentStatus) =>
+      val newValue = (currentStatus.b <*> Status.fromByte(c)) { (x, y) => (x & y) & 0xff }
+      currentStatus.copy(b = newValue, v = SingleFalse).nzB(newValue)
+    },
+    ADDA -> { (c, currentStatus) =>
+      val (newValue, newCarry) = currentStatus.a.adc(Status.fromByte(c), SingleFalse)
+      currentStatus.copy(a = newValue, v = AnyStatus, c = newCarry).nzB(newValue)
+    },
+    ADDB -> { (c, currentStatus) =>
+      val (newValue, newCarry) = currentStatus.b.adc(Status.fromByte(c), SingleFalse)
+      currentStatus.copy(b = newValue, v = AnyStatus, c = newCarry).nzB(newValue)
+    },
+    ADCA -> { (c, currentStatus) =>
+      val (newValue, newCarry) = currentStatus.a.adc(Status.fromByte(c), currentStatus.c)
+      currentStatus.copy(a = newValue, v = AnyStatus, c = newCarry).nzB(newValue)
+    },
+    ADCB -> { (c, currentStatus) =>
+      val (newValue, newCarry) = currentStatus.b.adc(Status.fromByte(c), currentStatus.c)
+      currentStatus.copy(b = newValue, v = AnyStatus, c = newCarry).nzB(newValue)
+    },
+  )
+
+  def hasDefinition(opcode: MOpcode.Value): Boolean = map.contains(opcode)
+
+  def get(opcode: MOpcode.Value): (Constant, CpuStatus) => CpuStatus = map(opcode)
+}

src/main/scala/millfork/assembly/m6809/opt/ForwardFlowAnalysisForInherent.scala

@@ -0,0 +1,28 @@
+package millfork.assembly.m6809.opt
+
+import millfork.assembly.m6809.MOpcode
+import millfork.assembly.m6809.MOpcode._
+import millfork.assembly.opt.Status.SingleFalse
+import millfork.assembly.opt.{AnyStatus, SingleStatus, Status}
+import millfork.env.Constant
+
+/**
+  * @author Karol Stasiak
+  */
+object ForwardFlowAnalysisForInherent {
+  private val map: Map[MOpcode.Value, CpuStatus => CpuStatus] = Map(
+    NOP -> identity,
+    MUL -> { currentStatus =>
+      val newD = (currentStatus.a <*> currentStatus.b) { (a, b) => ((a & 0xff) * (b & 0xff)) & 0xff }
+      currentStatus.copy(c = AnyStatus, z = AnyStatus, a = newD.hi, b = newD.hi)
+    },
+    SEX -> { currentStatus =>
+      val newA = currentStatus.b.map{ n => if (n.&(0x80) == 0) 0 else 0xff }
+      currentStatus.copy(v = Status.SingleFalse, n = AnyStatus, z = AnyStatus, a = newA)
+    },
+  )
+
+  def hasDefinition(opcode: MOpcode.Value): Boolean = map.contains(opcode)
+
+  def get(opcode: MOpcode.Value): CpuStatus => CpuStatus = map(opcode)
+}

src/main/scala/millfork/assembly/m6809/opt/ForwardFlowAnalysisForInherentA.scala

@@ -0,0 +1,47 @@
+package millfork.assembly.m6809.opt
+
+import millfork.assembly.m6809.MOpcode
+import millfork.assembly.m6809.MOpcode._
+import millfork.assembly.opt.{AnyStatus, SingleStatus, Status}
+
+/**
+  * @author Karol Stasiak
+  */
+object ForwardFlowAnalysisForInherentA {
+  private val map: Map[MOpcode.Value, CpuStatus => CpuStatus] = Map(
+    ASL -> { currentStatus =>
+      val newValue = currentStatus.a.map(n => n.<<(1).&(0xff))
+      currentStatus.copy(a = newValue, c = currentStatus.a.bit7, v = AnyStatus).nzB(newValue)
+    },
+    LSR -> { currentStatus =>
+      val newValue = currentStatus.a.map(n => n.>>(1).&(0x7f))
+      currentStatus.copy(a = newValue, c = currentStatus.a.bit0, v = AnyStatus).nzB(newValue)
+    },
+    CLR -> { currentStatus =>
+      currentStatus.copy(a = Status.SingleZero, c = Status.SingleFalse, v = Status.SingleFalse, n = Status.SingleFalse, z = Status.SingleFalse)
+    },
+    COM -> { currentStatus =>
+      val newValue = currentStatus.a.map(n => n.^(0xff).&(0xff))
+      currentStatus.copy(a = newValue, c = Status.SingleTrue, v = Status.SingleFalse).nzB(newValue)
+    },
+    DEC -> { currentStatus =>
+      val newValue = currentStatus.a.map(n => n.+(1).&(0xff))
+      currentStatus.copy(a = newValue, v = AnyStatus).nzB(newValue)
+    },
+    INC -> { currentStatus =>
+      val newValue = currentStatus.a.map(n => n.-(1).&(0xff))
+      currentStatus.copy(a = newValue, v = AnyStatus).nzB(newValue)
+    },
+    NEG -> { currentStatus =>
+      val newValue = currentStatus.a.map(n => (-n).&(0xff))
+      currentStatus.copy(a = newValue, c = AnyStatus, v = AnyStatus).nzB(newValue)
+    },
+    TST -> { currentStatus =>
+      currentStatus.copy(v = Status.SingleFalse).nzB(currentStatus.a)
+    },
+  )
+
+  def hasDefinition(opcode: MOpcode.Value): Boolean = map.contains(opcode)
+
+  def get(opcode: MOpcode.Value): CpuStatus => CpuStatus = map(opcode)
+}

src/main/scala/millfork/assembly/m6809/opt/ForwardFlowAnalysisForInherentB.scala

@@ -0,0 +1,47 @@
+package millfork.assembly.m6809.opt
+
+import millfork.assembly.m6809.MOpcode
+import millfork.assembly.m6809.MOpcode._
+import millfork.assembly.opt.{AnyStatus, Status}
+
+/**
+  * @author Karol Stasiak
+  */
+object ForwardFlowAnalysisForInherentB {
+  private val map: Map[MOpcode.Value, CpuStatus => CpuStatus] = Map(
+    ASL -> { currentStatus =>
+      val newValue = currentStatus.b.map(n => n.<<(1).&(0xff))
+      currentStatus.copy(b = newValue, c = currentStatus.b.bit7, v = AnyStatus).nzB(newValue)
+    },
+    LSR -> { currentStatus =>
+      val newValue = currentStatus.b.map(n => n.>>(1).&(0x7f))
+      currentStatus.copy(b = newValue, c = currentStatus.b.bit0, v = AnyStatus).nzB(newValue)
+    },
+    CLR -> { currentStatus =>
+      currentStatus.copy(b = Status.SingleZero, c = Status.SingleFalse, v = Status.SingleFalse, n = Status.SingleFalse, z = Status.SingleFalse)
+    },
+    COM -> { currentStatus =>
+      val newValue = currentStatus.b.map(n => n.^(0xff).&(0xff))
+      currentStatus.copy(b = newValue, c = Status.SingleTrue, v = Status.SingleFalse).nzB(newValue)
+    },
+    DEC -> { currentStatus =>
+      val newValue = currentStatus.b.map(n => n.+(1).&(0xff))
+      currentStatus.copy(b = newValue, v = AnyStatus).nzB(newValue)
+    },
+    INC -> { currentStatus =>
+      val newValue = currentStatus.b.map(n => n.-(1).&(0xff))
+      currentStatus.copy(b = newValue, v = AnyStatus).nzB(newValue)
+    },
+    NEG -> { currentStatus =>
+      val newValue = currentStatus.b.map(n => (-n).&(0xff))
+      currentStatus.copy(b = newValue, c = AnyStatus, v = AnyStatus).nzB(newValue)
+    },
+    TST -> { currentStatus =>
+      currentStatus.copy(v = Status.SingleFalse).nzB(currentStatus.b)
+    },
+  )
+
+  def hasDefinition(opcode: MOpcode.Value): Boolean = map.contains(opcode)
+
+  def get(opcode: MOpcode.Value): CpuStatus => CpuStatus = map(opcode)
+}

src/main/scala/millfork/assembly/m6809/opt/ReverseFlowAnalyzer.scala

@@ -1,5 +1,7 @@
 package millfork.assembly.m6809.opt
 
+import jdk.jfr.BooleanFlag
+import millfork.CompilationFlag
 import millfork.assembly._
 import millfork.assembly.m6809.{Absolute, MLine, MLine0, MOpcode, MState}
 import millfork.assembly.opt.FlowCache
@@ -81,6 +83,7 @@ object ReverseFlowAnalyzer {
   val readsB: Set[String] = Set("call")
   val readsX: Set[String] = Set("call")
   val readsY: Set[String] = Set("")
+  val preservesX: Set[String] = Set("__divmod_u8u8u8u8")
 
   val cache = new FlowCache[MLine, CpuImportance]("m6809 reverse")
   private val importanceBeforeJsr: CpuImportance = CpuImportance(
@@ -96,8 +99,8 @@ object ReverseFlowAnalyzer {
     hf = Unimportant)
   private val finalImportance: CpuImportance = CpuImportance(
     a = Important, b = Important,
-    x = Important, y = Important, u = Important,
+    x = Important, y = Important, u = Important, // TODO: correctly check which registers are important given the function and the compilation options
-    cf = Important, vf = Important, hf = Important, zf = Important, nf = Important)
+    cf = Unimportant, vf = Unimportant, hf = Unimportant, zf = Unimportant, nf = Unimportant)
 
   //noinspection RedundantNewCaseClass
   def analyze(f: NormalFunction, code: List[MLine], optimizationContext: OptimizationContext): List[CpuImportance] = {
@@ -108,9 +111,27 @@ object ReverseFlowAnalyzer {
 
     var changed = true
     changed = true
+    val actualFinalImportance = {
+      var tmp = f.returnType match {
+        case FlagBooleanType(_, _, _) => finalImportance.copy(cf = Important, zf = Important, nf = Important, vf = Important)
+        case t if t.size == 1 => finalImportance.copy(a = Unimportant)
+        case t if t.size == 0 => finalImportance.copy(a = Unimportant, b = Unimportant)
+        case _ => finalImportance
+      }
+      if (!f.inAssembly) {
+        tmp = tmp.copy(x = Unimportant)
+        if (!optimizationContext.options.flag(CompilationFlag.UseUForStack)) {
+          tmp = tmp.copy(u = Unimportant)
+        }
+        if (!optimizationContext.options.flag(CompilationFlag.UseYForStack)) {
+          tmp = tmp.copy(y = Unimportant)
+        }
+      }
+      tmp
+    }
     while (changed) {
       changed = false
-      var currentImportance = finalImportance
+      var currentImportance = actualFinalImportance
       for (i <- codeArray.indices.reverse) {
         import millfork.assembly.m6809.MOpcode._
         import millfork.node.M6809NiceFunctionProperty._
@@ -126,11 +147,22 @@ object ReverseFlowAnalyzer {
               case MLine0(LABEL, _, MemoryAddressConstant(Label(L))) => true
               case _ => false
             }
-            currentImportance = if (labelIndex < 0) finalImportance else importanceArray(labelIndex) ~ currentImportance
+            currentImportance = if (labelIndex < 0) actualFinalImportance else importanceArray(labelIndex) ~ currentImportance
+          case MLine0(JMP | BRA, _, MemoryAddressConstant(Label(l))) =>
+            val L = l
+            val labelIndex = codeArray.indexWhere {
+              case MLine0(LABEL, _, MemoryAddressConstant(Label(L))) => true
+              case _ => false
+            }
+            currentImportance = if (labelIndex < 0) actualFinalImportance else importanceArray(labelIndex)
           case _ =>
         }
         currentLine match {
 
+          case MLine0(RTS, _, _) =>
+            currentImportance = actualFinalImportance
+          case MLine0(LABEL, _, _) =>
+            // do nothing
           case MLine0(JSR | JMP, Absolute(false), MemoryAddressConstant(fun: FunctionInMemory)) =>
             // this case has to be handled first, because the generic JSR importance handler is too conservative
             var result = importanceBeforeJsr
@@ -161,6 +193,7 @@ object ReverseFlowAnalyzer {
             if (readsB(fun.name)) result = result.copy(b = Important)
             if (readsX(fun.name)) result = result.copy(x = Important)
             if (readsY(fun.name)) result = result.copy(y = Important)
+            if (preservesX(fun.name)) result = result.copy(x = currentImportance.x)
             currentImportance = result.copy(
               a = if (niceFunctionProperties(DoesntChangeA -> fun.name)) currentImportance.a ~ result.a else result.a,
               b = if (niceFunctionProperties(DoesntChangeB -> fun.name)) currentImportance.b ~ result.b else result.b,
@@ -173,7 +206,7 @@ object ReverseFlowAnalyzer {
           case MLine0(opcode, addrMode, _) =>
             if (MOpcode.ChangesC(opcode)) currentImportance = currentImportance.copy(cf = Unimportant)
             if (MOpcode.ChangesN(opcode)) currentImportance = currentImportance.copy(nf = Unimportant)
-            if (MOpcode.ChangesZ(opcode)) currentImportance = currentImportance.copy(zf = Unimportant)
+            if (MOpcode.ChangesH(opcode)) currentImportance = currentImportance.copy(hf = Unimportant)
             if (MOpcode.ChangesZ(opcode)) currentImportance = currentImportance.copy(zf = Unimportant)
             if (MOpcode.ReadsC(opcode)) currentImportance = currentImportance.copy(cf = Important)
             if (MOpcode.ReadsH(opcode)) currentImportance = currentImportance.copy(hf = Important)

src/main/scala/millfork/assembly/m6809/opt/RuleBasedAssemblyOptimization.scala

@@ -30,42 +30,52 @@ object FlowInfoRequirement extends Enumeration {
   }
 
   def assertLabels(x: FlowInfoRequirement.Value): Unit = x match {
-    case NoRequirement => FatalErrorReporting.reportFlyingPig("Backward flow info required")
+    case NoRequirement => FatalErrorReporting.reportFlyingPig("Label info required")
     case _ => ()
   }
 }
 
 trait AssemblyRuleSet{
   def flatten: Seq[AssemblyRule]
+
+  def minimumRequiredLines: Int
 }
 
 class RuleBasedAssemblyOptimization(val name: String, val needsFlowInfo: FlowInfoRequirement.Value, val rules: AssemblyRuleSet*) extends AssemblyOptimization[MLine] {
 
   private val actualRules = rules.flatMap(_.flatten)
   actualRules.foreach(_.pattern.validate(needsFlowInfo))
+  private val actualRulesWithIndex = actualRules.zipWithIndex
 
+  override val minimumRequiredLines: Int = rules.map(_.minimumRequiredLines).min
+
+  override def toString: String = name
 
   override def optimize(f: NormalFunction, code: List[MLine], optimizationContext: OptimizationContext): List[MLine] = {
     val taggedCode = FlowAnalyzer.analyze(f, code, optimizationContext, needsFlowInfo)
-    val (changed, optimized) = optimizeImpl(f, taggedCode, optimizationContext)
+    optimizeImpl(f, code, taggedCode, optimizationContext)
-    if (changed) optimized else code
   }
 
-  def optimizeImpl(f: NormalFunction, code: List[(FlowInfo, MLine)], optimizationContext: OptimizationContext): (Boolean, List[MLine]) = {
+  final def optimizeImpl(f: NormalFunction, code: List[MLine], taggedCode: List[(FlowInfo, MLine)], optimizationContext: OptimizationContext): List[MLine] = {
     val log = optimizationContext.log
-    code match {
+    taggedCode match {
-      case Nil => false -> Nil
+      case Nil => code
       case head :: tail =>
-        for ((rule, index) <- actualRules.zipWithIndex) {
+        val codeLength = code.length
+        for {
+          (rule, index) <- actualRulesWithIndex
+          if codeLength >= rule.minimumRequiredLines
+        } {
           val ctx = new AssemblyMatchingContext(
             optimizationContext.options,
             optimizationContext.labelMap,
             optimizationContext.niceFunctionProperties,
             head._1.labelUseCount(_)
           )
-          rule.pattern.matchTo(ctx, code) match {
+          rule.pattern.matchTo(ctx, taggedCode) match {
             case Some(rest: List[(FlowInfo, MLine)]) =>
-              val matchedChunkToOptimize: List[MLine] = code.take(code.length - rest.length).map(_._2)
+              val optimizedChunkLengthBefore = taggedCode.length - rest.length
+              val (matchedChunkToOptimize, restOfCode) = code.splitAt(optimizedChunkLengthBefore)
               val optimizedChunk: List[MLine] = rule.result(matchedChunkToOptimize, ctx)
               val optimizedChunkWithSource =
                 if (!ctx.compilationOptions.flag(CompilationFlag.LineNumbersInAssembly)) optimizedChunk
@@ -74,34 +84,40 @@ class RuleBasedAssemblyOptimization(val name: String, val needsFlowInfo: FlowInf
                 else if (optimizedChunk.size == 1) optimizedChunk.map(_.pos(SourceLine.merge(matchedChunkToOptimize.map(_.source))))
                 else if (matchedChunkToOptimize.flatMap(_.source).toSet.size == 1) optimizedChunk.map(_.pos(SourceLine.merge(matchedChunkToOptimize.map(_.source))))
                 else optimizedChunk
-              log.debug(s"Applied $name ($index)")
+              if (log.debugEnabled) {
-              if (needsFlowInfo != FlowInfoRequirement.NoRequirement) {
+                log.debug(s"Applied $name ($index)")
-                val before = code.head._1.statusBefore
-                val after = code(matchedChunkToOptimize.length - 1)._1.importanceAfter
-                log.trace(s"Before: $before")
-                log.trace(s"After:  $after")
               }
               if (log.traceEnabled) {
+                if (needsFlowInfo != FlowInfoRequirement.NoRequirement) {
+                  val before = head._1.statusBefore
+                  val after = taggedCode(matchedChunkToOptimize.length - 1)._1.importanceAfter
+                  log.trace(s"Before: $before")
+                  log.trace(s"After:  $after")
+                }
                 matchedChunkToOptimize.filter(_.isPrintable).foreach(l => log.trace(l.toString))
                 log.trace("     ↓")
                 optimizedChunkWithSource.filter(_.isPrintable).foreach(l => log.trace(l.toString))
               }
               if (needsFlowInfo != FlowInfoRequirement.NoRequirement) {
-                return true -> (optimizedChunkWithSource ++ optimizeImpl(f, rest, optimizationContext)._2)
+                return optimizedChunkWithSource ++ optimizeImpl(f, restOfCode, rest, optimizationContext)
               } else {
-                return true -> optimize(f, optimizedChunkWithSource ++ rest.map(_._2), optimizationContext)
+                return optimize(f, optimizedChunkWithSource ++ restOfCode, optimizationContext)
               }
             case None => ()
           }
         }
-        val (changedTail, optimizedTail) = optimizeImpl(f, tail, optimizationContext)
+        val optimizedTail = optimizeImpl(f, code.tail, tail, optimizationContext)
-        (changedTail, head._2 :: optimizedTail)
+        if (optimizedTail eq code.tail) {
+          code
+        } else {
+          code.head :: optimizedTail
+        }
     }
   }
 }
 
 class AssemblyMatchingContext(val compilationOptions: CompilationOptions,
-                              val labelMap: Map[String, (Int, Int)],
+                              val labelMap: Map[String, (String, Int)],
                               val niceFunctionProperties: Set[(NiceFunctionProperty, String)],
                               val labelUseCount: String => Int) {
   @inline
@@ -211,10 +227,14 @@ class AssemblyMatchingContext(val compilationOptions: CompilationOptions,
 
 case class AssemblyRule(pattern: AssemblyPattern, result: (List[MLine], AssemblyMatchingContext) => List[MLine]) extends AssemblyRuleSet {
   override def flatten: Seq[AssemblyRule] = List(this)
+
+  override def minimumRequiredLines: Int = pattern.minimumRequiredLines
 }
 
 case class MultipleAssemblyRules(list: Seq[AssemblyRuleSet]) extends AssemblyRuleSet {
   override def flatten: Seq[AssemblyRule] = list.flatMap(_.flatten)
+
+  override val minimumRequiredLines: Int = flatten.map(_.minimumRequiredLines).sum
 }
 
 trait AssemblyPattern {
@@ -235,6 +255,8 @@ trait AssemblyPattern {
 
   def captureLength(i: Int) = CaptureLength(i, this)
 
+  def minimumRequiredLines: Int
+
 }
 object HelperCheckers {
   private def badAddrModes(am: MAddrMode): Boolean = am match {
@@ -337,6 +359,8 @@ case class Capture(i: Int, pattern: AssemblyPattern) extends AssemblyPattern {
     }
 
   override def toString: String = s"(?<$i>$pattern)"
+
+  override def minimumRequiredLines: Int = 0
 }
 
 case class CaptureLength(i: Int, pattern: AssemblyPattern) extends AssemblyPattern {
@@ -349,6 +373,8 @@ case class CaptureLength(i: Int, pattern: AssemblyPattern) extends AssemblyPatte
     }
 
   override def toString: String = s"(?<$i>$pattern)"
+
+  override def minimumRequiredLines: Int = 0
 }
 
 
@@ -358,6 +384,8 @@ case class Where(predicate: AssemblyMatchingContext => Boolean) extends Assembly
   }
 
   override def toString: String = "Where(...)"
+
+  override def minimumRequiredLines: Int = 0
 }
 
 case class Concatenation(l: AssemblyPattern, r: AssemblyPattern) extends AssemblyPattern {
@@ -380,6 +408,8 @@ case class Concatenation(l: AssemblyPattern, r: AssemblyPattern) extends Assembl
     case (_: Both, _) => s"($l) · $r"
     case _ => s"$l · $r"
   }
+
+  override val minimumRequiredLines: Int = l.minimumRequiredLines + r.minimumRequiredLines
 }
 
 case class Many(rule: MLinePattern) extends AssemblyPattern {
@@ -405,6 +435,8 @@ case class Many(rule: MLinePattern) extends AssemblyPattern {
   }
 
   override def toString: String = s"[$rule]*"
+
+  override def minimumRequiredLines: Int = 0
 }
 
 case class ManyWhereAtLeastOne(rule: MLinePattern, atLeastOneIsThis: MLinePattern) extends AssemblyPattern {
@@ -439,6 +471,8 @@ case class ManyWhereAtLeastOne(rule: MLinePattern, atLeastOneIsThis: MLinePatter
   }
 
   override def toString: String = s"[∃$atLeastOneIsThis:$rule]*"
+
+  override def minimumRequiredLines: Int = 1
 }
 
 case class Opt(rule: MLinePattern) extends AssemblyPattern {
@@ -461,6 +495,8 @@ case class Opt(rule: MLinePattern) extends AssemblyPattern {
   }
 
   override def toString: String = s"[$rule]?"
+
+  override def minimumRequiredLines: Int = 0
 }
 
 trait MLinePattern extends AssemblyPattern {
@@ -488,6 +524,8 @@ trait MLinePattern extends AssemblyPattern {
     else Both(x, this)
 
   def hitRate: Double
+
+  override def minimumRequiredLines: Int = 1
 }
 
 //noinspection ScalaUnnecessaryParentheses
@@ -509,6 +547,8 @@ case class WhereNoMemoryAccessOverlapBetweenTwoLineLists(ix1: Int, ix2: Int) ext
     val s2s = ctx.get[List[MLine]](ix2)
     if (s1s.forall(s1 => s2s.forall(s2 => HelperCheckers.memoryAccessDoesntOverlap(s1, s2)))) Some(code) else None
   }
+
+  override def minimumRequiredLines: Int = 0
 }
 
 case class MatchA(i: Int) extends MLinePattern {
@@ -754,6 +794,8 @@ case object DebugMatching extends AssemblyPattern {
     code.foreach(println)
     Some(code)
   }
+
+  override def minimumRequiredLines: Int = 0
 }
 
 case object Linear extends MLinePattern {
@@ -1274,6 +1316,8 @@ case class MatchElidableCopyOf(i: Int, firstLinePattern: MLinePattern, lastLineP
     }
     Some(after)
   }
+
+  override def minimumRequiredLines: Int = 0
 }
 
 case object IsNotALabelUsedManyTimes extends MLinePattern {
@@ -1290,3 +1334,14 @@ case object IsNotALabelUsedManyTimes extends MLinePattern {
 
   override def hitRate: Double = 0.92 // ?
 }
+
+
+object ParameterIsLocalLabel extends MLinePattern {
+  override def matchLineTo(ctx: AssemblyMatchingContext, flowInfo: FlowInfo, line: MLine): Boolean =
+    line match {
+      case MLine0(MOpcode.LABEL, _, MemoryAddressConstant(Label(l))) => l.startsWith(".")
+      case _ => false
+    }
+
+  override def hitRate: Double = 0.056
+}

src/main/scala/millfork/assembly/mos/AssemblyLine.scala

@@ -693,6 +693,8 @@ case class AssemblyLine(opcode: Opcode.Value, addrMode: AddrMode.Value, var para
       parameter match {
         case StructureConstant(_, List(a,b)) => s"    $opcode $a,$b"
       }
+    } else if (addrMode == LongRelative && opcode != BSR) { // BSR on Hudson is always 8-bit short, and on 65CE02 it's always 16-bit
+      s"    L$opcode ${AddrMode.addrModeToString(addrMode, parameter.toString)}"
     } else if (addrMode == ImmediateWithAbsolute || addrMode == ImmediateWithZeroPage) {
       parameter match {
         case StructureConstant(_, List(a,b)) => s"    $opcode #$a,$b"

src/main/scala/millfork/assembly/mos/Opcode.scala

@@ -180,20 +180,31 @@ object Opcode extends Enumeration {
     case "AXA" => AHX
     case "AXS" => SBX // could mean SAX
     case "BCC" => BCC
+    case "LBCC" => BCC
     case "BCS" => BCS
+    case "LBCS" => BCS
     case "BEQ" => BEQ
+    case "LBEQ" => BEQ
     case "BIT" => BIT
     case "BMI" => BMI
+    case "LBMI" => BMI
     case "BNE" => BNE
+    case "LBNE" => BNE
     case "BPL" => BPL
+    case "LBPL" => BPL
     case "BRA" => BRA
+    case "LBRA" => BRA
     case "BRK" => BRK
     case "BRL" => BRL
     case "BSR" => BSR
+    case "LBSR" => BSR
     case "BVC" => BVC
+    case "LBVC" => BVC
     case "BVS" => BVS
+    case "LBVS" => BVS
     case "CLC" => CLC
     case "CLD" => CLD
+    case "CLE" => CLE
     case "CLI" => CLI
     case "CLV" => CLV
     case "CLX" => CLX
@@ -232,6 +243,7 @@ object Opcode extends Enumeration {
     case "LSE" => SRE
     case "LSR" => LSR
     case "LXA" => LXA
+    case "MAP" => MAP
     case "NEG" => NEG
     case "NOP" => NOP
     case "OAL" => LXA
@@ -247,17 +259,19 @@ object Opcode extends Enumeration {
     case "PHW" => PHW
     case "PHX" => PHX
     case "PHY" => PHY
+    case "PHZ" => PHZ
     case "PLA" => PLA
     case "PLB" => PLB
     case "PLD" => PLD
     case "PLP" => PLP
     case "PLX" => PLX
     case "PLY" => PLY
+    case "PLZ" => PLZ
     case "REP" => REP
     case "RLA" => RLA
     case "ROL" => ROL
     case "ROR" => ROR
-    case "ROW" => ROR_W // TODO: is this correct?
+    case "ROW" => ROL_W
     case "RRA" => RRA
     case "RTI" => RTI
     case "RTL" => RTL
@@ -268,6 +282,7 @@ object Opcode extends Enumeration {
     case "SBX" => SBX
     case "SEC" => SEC
     case "SED" => SED
+    case "SEE" => SEE
     case "SEI" => SEI
     case "SEP" => SEP
     case "SET" => SET

src/main/scala/millfork/assembly/mos/opt/AlwaysGoodOptimizations.scala

@@ -995,16 +995,10 @@ object AlwaysGoodOptimizations {
 
   val ConstantFlowAnalysis = new RuleBasedAssemblyOptimization("Constant flow analysis",
     needsFlowInfo = FlowInfoRequirement.ForwardFlow,
-    (MatchX(0) & HasAddrMode(AbsoluteX) & SupportsAbsolute & Elidable & HasParameterWhere({
+    (MatchX(0) & HasAddrMode(AbsoluteX) & SupportsAbsolute & Not(HasOpcode(BIT)) & Elidable & HasIdentityPageParameter) ~~> { (code, ctx) =>
-      case MemoryAddressConstant(th) => th.name == "identity$"
-      case _ => false
-    })) ~~> { (code, ctx) =>
       code.map(l => l.copy(addrMode = Immediate, parameter = NumericConstant(ctx.get[Int](0), 1)))
     },
-    (MatchY(0) & HasAddrMode(AbsoluteY) & SupportsAbsolute & Elidable & HasParameterWhere({
+    (MatchY(0) & HasAddrMode(AbsoluteY) & SupportsAbsolute & Elidable & HasIdentityPageParameter) ~~> { (code, ctx) =>
-      case MemoryAddressConstant(th) => th.name == "identity$"
-      case _ => false
-    })) ~~> { (code, ctx) =>
       code.map(l => l.copy(addrMode = Immediate, parameter = NumericConstant(ctx.get[Int](0), 1)))
     },
     (MatchY(0) & HasAddrMode(AbsoluteY) & SupportsAbsolute & Elidable) ~~> { (code, ctx) =>
@@ -1605,6 +1599,15 @@ object AlwaysGoodOptimizations {
       Where(ctx => ctx.get[Int](1).&(1) == 0)~~> { (lines, ctx) =>
       lines.head.copy(opcode = ASL) :: lines.tail
     },
+    (Elidable & HasOpcode(LDA)) ~
+    (Elidable & HasOpcode(AND) & HasAddrMode(Immediate) & MatchParameter(0)) ~
+    (Elidable & HasOpcode(BNE) & MatchParameter(1)) ~
+    (Elidable & HasOpcode(LDA)) ~
+    (Elidable & HasOpcode(AND) & HasAddrMode(Immediate) & MatchParameter(0)) ~
+      (Elidable & HasOpcode(BEQ)) ~
+      (Elidable & HasOpcode(LABEL) & MatchParameter(1)) ~~> { (code, ctx) =>
+      List(code.head, code(3).copy(opcode = ORA)) ++ code.drop(4)
+    },
   )
 
   val SimplifiableIndexChanging = new RuleBasedAssemblyOptimization("Simplifiable index changing",
@@ -2065,7 +2068,7 @@ object AlwaysGoodOptimizations {
 
   val UnusedLabelRemoval = new RuleBasedAssemblyOptimization("Unused label removal",
     needsFlowInfo = FlowInfoRequirement.JustLabels,
-    (Elidable & HasOpcode(LABEL) & HasCallerCount(0)) ~~> (_ => Nil)
+    (Elidable & HasOpcode(LABEL) & HasCallerCount(0) & ParameterIsLocalLabel) ~~> (_ => Nil)
   )
 
   val OperationsAroundShifting = new RuleBasedAssemblyOptimization("Operations around shifting",
@@ -2982,7 +2985,9 @@ object AlwaysGoodOptimizations {
 
     (Elidable & HasOpcode(EOR) & MatchImmediate(0)) ~
       (Elidable & HasOpcode(CMP) & MatchImmediate(1) & DoesntMatterWhatItDoesWith(State.A, State.N, State.C)) ~~> { (code, ctx) =>
-      List(code.last.copy(parameter = CompoundConstant(MathOperator.Exor, ctx.get[Constant](0), ctx.get[Constant](1))))
+      val c0 = ctx.get[Constant](0)
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = CompoundConstant(MathOperator.Exor, c0, c1).quickSimplify))
     },
 
     MultipleAssemblyRules(for {
@@ -3106,6 +3111,42 @@ object AlwaysGoodOptimizations {
         code(1).copy(opcode = branch, parameter = code(3).parameter),
         code(4))
     },
+
+    (Elidable & HasOpcode(INC) & HasAddrMode(Implied)) ~
+    (Elidable & HasOpcode(CMP) & HasAddrMode(Immediate) & MatchParameter(1) & DoesntMatterWhatItDoesWith(State.N, State.A, State.C, State.V)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 - 1).quickSimplify))
+    },
+
+    (Elidable & HasOpcode(INX) & HasAddrMode(Implied)) ~
+    (Elidable & HasOpcode(CPX) & HasAddrMode(Immediate) & MatchParameter(1) & DoesntMatterWhatItDoesWith(State.N, State.X, State.C, State.V)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 - 1).quickSimplify))
+    },
+
+    (Elidable & HasOpcode(INY) & HasAddrMode(Implied)) ~
+    (Elidable & HasOpcode(CPY) & HasAddrMode(Immediate) & MatchParameter(1) & DoesntMatterWhatItDoesWith(State.N, State.Y, State.C, State.V)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 - 1).quickSimplify))
+    },
+
+    (Elidable & HasOpcode(DEC) & HasAddrMode(Implied)) ~
+    (Elidable & HasOpcode(CMP) & HasAddrMode(Immediate) & MatchParameter(1) & DoesntMatterWhatItDoesWith(State.N, State.A, State.C, State.V)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 + 1).quickSimplify))
+    },
+
+    (Elidable & HasOpcode(DEX) & HasAddrMode(Implied)) ~
+    (Elidable & HasOpcode(CPX) & HasAddrMode(Immediate) & MatchParameter(1) & DoesntMatterWhatItDoesWith(State.N, State.X, State.C, State.V)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 + 1).quickSimplify))
+    },
+
+    (Elidable & HasOpcode(DEY) & HasAddrMode(Implied)) ~
+    (Elidable & HasOpcode(CPY) & HasAddrMode(Immediate) & MatchParameter(1) & DoesntMatterWhatItDoesWith(State.N, State.Y, State.C, State.V)) ~~> { (code, ctx) =>
+      val c1 = ctx.get[Constant](1)
+      List(code.last.copy(parameter = (c1 + 1).quickSimplify))
+    },
   )
 
   private val powersOf2: List[(Int, Int)] = List(