From b469ceef8c1cd10d9a5e04cb3cb5672bedf2a438 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Carl-Henrik=20Sk=C3=A5rstedt?= <cskarstedt@gmail.com>
Date: Sat, 11 Jan 2020 12:58:26 -0800
Subject: [PATCH] Expermenting with starting over on the x65 documentation

---
 docs/command_line_options.md | 116 +++++++++
 docs/directives.md           | 472 +++++++++++++++++++++++++++++++++++
 docs/macro_samples.md        | 164 ++++++++++++
 docs/readme.md               |  48 ++++
 macros/x65macro.i            |   2 +-
 5 files changed, 801 insertions(+), 1 deletion(-)
 create mode 100644 docs/command_line_options.md
 create mode 100644 docs/directives.md
 create mode 100644 docs/macro_samples.md
 create mode 100644 docs/readme.md

diff --git a/docs/command_line_options.md b/docs/command_line_options.md
new file mode 100644
index 0000000..64a074b
--- /dev/null
+++ b/docs/command_line_options.md
@@ -0,0 +1,116 @@
+# Command Line Options for x65
+
+These are the current options for controlling x65 from the command line.
+
+## lst
+	-lst / -lst=(file.lst)
+
+Generate disassembly text from result(file or stdout)
+
+## tsl
+	-tsl=(file)
+	
+generate listing file in TASS style
+
+## tl
+	
+	-tl=(file)
+	
+Generate labels in TASS style
+
+## opcodes
+	-opcodes / -opcodes=(file.s)
+	
+Use with -cpu=... to dump all available opcodes for that CPU (file or stdout)
+
+## endm
+	-endm
+	
+macros end with endm or endmacro instead of scoped('{' - '}') and rept/repeat emds with endr instead of being scoped.
+
+## cpu
+	-cpu=[6502/6502ill/65c02/65c02wdc/65816]
+
+declare CPU type, use with argument
+
+## acc [65816]
+	-acc=[8/16]
+	
+set the accumulator mode for 65816 at start, default is 8 bits
+
+## xy [65816]
+	-xy=8/16
+	
+set the index register mode for 65816 at start, default is 8 bits
+
+
+## org
+	-org=$2000 or -org=4096
+	
+force assembly for first encountered non-specific address section at given address
+
+## kickasm
+	-kickasm
+
+use Kick Assembler syntax (in progress)
+
+## merlin
+	-merlin
+
+use Merlin syntax
+
+## c64
+	-c64
+
+(default) Include 2 byte load address in binary output
+
+## a2b
+	-a2b
+	
+Produce an Apple II Dos 3.3 Binary
+
+## bin
+	-bin
+
+Produce raw binary
+
+## a2p
+	-a2p
+	
+Produce an Apple II ProDos Binary
+
+## a2o
+	-a2o
+
+Produce an Apple II GS OS executable (relocatable)
+
+## mrg
+	-mrg
+	
+Force merge all sections (use with -a2o)
+
+## sect
+	-sect
+
+display sections loaded and built
+
+## sym
+	-sym (file.sym)
+	
+generate symbol file
+
+## obj
+	-obj (file.x65)
+	
+Produce an object file instead of a binary for later linking
+
+## vice
+	-vice (file.vs)
+
+export a vice monitor command file (including vice symbols)
+
+## xrefimp
+	-xrefimp
+	
+import directive means xref, not include/incbin and export directive means xdef, not export section.
+
diff --git a/docs/directives.md b/docs/directives.md
new file mode 100644
index 0000000..67a85ea
--- /dev/null
+++ b/docs/directives.md
@@ -0,0 +1,472 @@
+# X65 Directives
+
+Directives are commands that control the assembler and include controls for conditional assembly, exporting multible binary files, creating linkable object files etc.
+
+The directives are case insensitive and can be preceeded by a dot
+
+	.rept 8 { dc.b 1<<rept }
+
+is the same as
+
+	REPT 8 { dc.b 1<<rept }
+
+Some directives change behavior
+
+
+## CPU, PROCESSOR
+
+Assemble for this target, valid options are:
+ * 6502
+ * 6502ill (illegal opcodes)
+ * 65c02
+ * 6502wdc (adds 18 extra instructions: stp, wai, bbr0-7 & bbs0-7)
+ * 65816
+
+example:
+
+	cpu 6502ill
+
+## PC, ORG
+
+Assemble as if loaded at this address
+
+## LOAD
+
+If applicable, instruct to load at this address
+
+## EXPORT
+
+Export this section or disable export Note that with the -xdefimp command line option this means XDEF instead and the EXPORT directive is not available.
+
+## SECTION, SEG, SEGMENT
+
+Enable code that will be assigned a start address during a link step, or alternatively its own load address. BSS and ZP sections will not be included in the binary output, and sections can be separately exported using the EXPORT directive.
+
+## MERGE
+
+Merge named sections in order listed
+
+## LINK
+
+Put sections with this name at this address (must be ORG / fixed address section)
+
+## XDEF
+
+Externally declare a symbol. When using the command line option -xdefimp EXPORT means the same thing.
+
+## XREF
+
+Reference an external symbol. When using the command line option -xdefimp IMPORT means the same thing.
+
+## INCOBJ
+
+Read in an object file saved from a previous build (that was assembled using the -obj command line option).
+
+## ALIGN
+
+Add to address to make it evenly divisible by this. This only works at the start of a SECTION or in the middle of a section that is assembled to a fixed address.
+
+## MACRO, MAC
+
+Create a macro. When used with the command line option -endm the macro ends with a ENDMACRO or ENDM directive, and if not using -endm the macro is defined within braces ( { and } ).
+
+	; standard macro usage
+	MACRO ldaneg(x) {
+		lda #-x
+	}
+
+	; -endm macro usage
+	MACRO ldaneg(x)
+		lda #-x
+	ENDM
+
+
+## EVAL, PRINT, ECHO
+
+Print expression to stdout during assemble. The syntax is:
+
+	EVAL <message>: <expression>
+
+for example
+
+	EVAL Current Address: *
+
+	test_stack = 0
+	eval Checking referenced function, Should be 0: .referenced(test_stack)
+	eval Checking defined function, Should be 1: .defined(test_stack)
+
+## DC, DV
+
+Declare constant / Declare Value. The directive can be specific by appending .b for byte size, .w for word size, .t for triple size or .l for long size. The default size is 1 byte.
+
+	Test:
+	  dc.b $20, *-Test
+
+## BYTE, BYTES
+
+Same as dc.b
+
+## WORD, WORDS
+
+Same as dc.w
+
+## LONG
+
+Same as dc.l
+
+## TEXT
+
+Add text to output, the order of characters can be changed with a string symbol, for instance:
+
+	STRING FontOrder = " ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!#$%&*"
+	TEXT [FontOrder] "HELLO #1!"
+
+## INCLUDE
+
+Load and assemble another file at this address.
+
+## INCBIN
+
+Load another file and include as binary data at this address.
+
+## INCSYM
+
+Load symbols from a .sym file
+
+	INCSYM "Main.Sym"
+
+Symbols can also be selected by a list on the same line:
+
+	INCSYM InitMain, UpdateMain, ShutdownMain, "Main.Sym"
+
+## INCDIR
+
+Add a folder to search for include files.
+
+## IMPORT
+
+Generic version of INCLUDE, INCBIN with custom arguments
+
+	; include a raw binary file
+	IMPORT "data.bin"
+	IMPORT binary "data.bin"
+
+	; include a source file
+	IMPORT source "defines.i"
+
+	; include a binary C64 file omitting the load address (first 2 bytes)
+	IMPORT c64 "main.prg"
+
+	; include a text file
+	IMPORT text "text.txt"
+	IMPORT text petscii "petscii.txt"
+	IMPORT text petscii_shifted "petscii.txt"
+	IMPORT text <string symbol> "custom.txt"	; see TEXT directive
+
+Note that if the command line argument -xdefimp is used then IMPORT is equivalent to XREF instead.
+
+## CONST
+
+Declare a symbol as const, assgning it again will cause an error.
+
+	CONST VICBank = $4000
+
+The constness of a symbol can be tested with the IFCONST directive or the CONST() eval function.
+
+## LABEL
+
+Optional directive create a mutable label, a way to specify non-CONST. It has no actual function.
+
+## STRING
+
+Declare a string symbol. Strings are a little bit limited but can be used for ordering characters in a TEXT declaration, or it can be used as assembler source.
+
+	; Some custom ordered text
+	TEXT [FontOrder] "MAKE IT SO!"
+
+	; Macro for (x=start; x<end; x++)
+	macro for.x Start, End {
+	ldx #Start
+	if Start < End
+		string _ForEnd = "inx\ncpx #End\nbne _ForLoop"
+	elif Start > End
+	{
+		if (-1 == End) & (Start<129)
+		string _ForEnd = "dex\nbpl _ForLoop"
+		else
+		string _ForEnd = "dex\ncpx #End\nbne _ForLoop"
+		endif
+	}
+	else
+		string _ForEnd = ""
+	endif
+	_ForLoop
+	}
+
+	macro forend {
+		_ForEnd			; _ForEnd defined by a variation of the for macro
+		undef _ForEnd
+		undef _ForLoop
+	}
+
+	for.x(5, 1)
+		lda buf1,x
+		sta buf2,x
+	forend
+
+## UNDEF
+
+Remove a symbol
+
+	like_bananas = 1
+	UNDEF like_bananas
+
+## LABPOOL, POOL
+
+Create a pool of addresses to assign as labels dynamically. This acts as a linear stack allocator for temporary storage and is deallocated when the scope ends if declared as a local symbol.
+
+Pools can be defined as part of a larger pool.
+
+	pool zpGlobal $40-$f8		; all zero page usage
+	zpGlobal pool zpLocal 16	; temporary storage for regular functions
+	zpGlobal pool zpUtility 16	; temporary storage for utility functions
+	zpGlobal pool zpInterrupt 8	; temporary storage for interrupts
+	zpGlobal pool zpBuffer 64	; per module storage
+
+Allocate from a pool by using the pool name
+
+	zpBuffer zpIntroTimer.w		; frame counter, 2 bytes
+	zpBuffer zpScrollChar.8		; 8 bytes of rol char for scroll
+
+	{
+		zpLocal .zpSrc.w		; 2 bytes source address
+		zpLocal .zpDst.w		; 2 bytes dest address
+		..
+	}							; at this point .zpSrc and .zpDst are deallocated and can be reused by other code.
+	{
+		zpLocal .zpCount		; 1 byte, same address as .zpSrc used above
+	}
+
+## IF
+
+Begin conditional code. Whatever lines follow will be assembled only if the expression following the IF evaluates to a non-zero value, the conditional block ends with ELSE, ELSEIF or ENDIF.
+	
+	conditional_code = 1
+	IF conditional_code
+		...				; this will be assembled because conditional_code is not zero
+	ENDIF
+
+## IFDEF, IFNDEF
+
+Similar to IF but only takes one symbol and the following lines will be assembled only if the symbol was defined previously (IFDEF) or not defined previously (IFNDEF)
+
+	defined_symbol = 0
+	IFDEF defined_symbol
+		...				; this will be assembled because defined_symbol exists
+	ENDIF
+
+## IFCONST
+
+Similar to IF but like IFDEF only takes one symbol and the following lines will be assembled if the symbol is CONST. The symbol should be defined prior to testing it.
+
+CONST() is also an Eval Function that can be used to form more complex expressions using IF. IFCONST is equivalent to IF CONST(<symbol>)
+
+## IFBLANK, IFNBLANK
+
+Checks if the argument exists, mostly for use in macros to test if an argument exists.
+
+BLANK() is also an Eval Function, IFBLANK is equivalent to IF BLANK(...)
+
+## ELSE
+
+Requires a prior IF, the following line will be assembled only if the prior conditional block was not assembled. ELSE must be terminated by an ENDIF
+
+	IF 1
+		lda #0
+	ELSE
+		lda #2
+	ENDIF
+
+## ELIF
+
+Requires a prior IF and allows another expression check before ending the conditional blocks
+
+	IFDEF monkey
+		lda #monkey_value
+	ELIF DEFINED(zebra)
+		lda #zebra_value
+	ELSE
+		lda #human_value
+	ENDIF
+
+## ENDIF
+
+Terminated a conditional segment of blocks.
+
+## STRUCT
+
+Declare a set of labels offset from a base address.
+
+Example:
+
+	STRUCT ArtSet {
+		word ArtTiles
+		word ArtColors
+		word ArtMasks
+		byte bgColor
+	}
+
+Members of the structure can be referenced by the struct name dot member name:
+
+	lda ArtSetData + ArtSet.bgColor
+
+	ArtSetData:
+		ds SIZEOF(ArtSet)
+
+## ENUM
+
+Declare a set of incremental labels. Values can either be assigned or one more than the previous. The default first value is 0.
+
+	enum PlayerIndex {
+		None = -1,
+		One,
+		Two
+		Three,
+		Four,
+		Count		; there are this many players
+	}
+
+Enum values can be referenced by enum name dot value name:
+
+	ldx #PlayerIndex.One
+	{
+		inx
+		cpx #PlayerIndex.Count
+		bcc !
+	}
+
+	lda #PlayerIndex.Four
+
+## REPT, REPEAT
+
+Repeats the code within { and } following the REPT directive and counter. Within the REPT code the symbol REPT has the current iteration count, starting at 0.
+
+	const words = 10
+
+	.rept words * 2 { dc.b rept / 2 }
+
+If the command line option -endm is used then REPT uses ENDR instead of the braced scope so the equivalent to the above would be
+	
+	.rept words * 2
+		dc.b rept / 2
+	.endr
+
+## A16, A8, XY16, XY8, I16, I8
+
+Specific to 65816 assembly, controls the current accumulator and index register width (8 or 16 bits). Different assemblers use different names so various alternatives are allowed.
+
+## DUMMY, DUMMY_END
+
+Creates a dummy section between DUMMY and DUMMY_END directives.
+
+## DS, RES
+
+Define "section", Reserve. Reserves a number of bytes at the current address. The first argument is the number of bytes and the second argument is optional and is the byte to fill with. The main purpose is to reserve space in a BSS or ZP section.
+
+## SCOPE, ENDSCOPE
+
+A specialized version of a scope, does the same this as a brace scope (code between { and }) but additionally marks all labels defined within as local. An unimplemented feature is that the scope can be named and then labels defined can be accessed outside the scope as
+
+<scope name>::<label> or <scope name>.label (TODO!)
+
+## PUSH, PULL
+
+Creates a stack for a mutable symbol so that it can temporarily be redefined and then restored.
+
+	do_thing = 1
+
+	IF do_thing
+		..			; do thing
+	ENDIF
+
+	PUSH do_thing
+	do_thing = 0
+
+	IF do_thing
+		..			; do not do thing
+	ENDIF
+
+	PULL do_thing
+
+	IF do_thing
+		..			; restored symbol, let's do thing again!
+	ENDIF
+
+## ABORT, ERR
+
+Stops assembly with an error if encountered and prints the rest of the line to the output.
+
+---
+
+
+# Merlin Specific Directives
+
+## MX
+
+## STR
+
+## DA
+
+## DN
+
+## ASC
+
+## PUT
+
+## DDB
+
+## DB
+
+## DFB
+
+## HEX
+
+## DO
+
+## FIN
+
+## EJECT
+
+## OBJ
+
+## TR
+
+## END
+
+## REL
+
+## USR
+
+## DUM
+
+## DEND
+
+## LST, LSTDO
+
+## LUP
+
+## SAV, DSK
+
+## LNK
+
+## XC
+
+## ENT
+
+## EXT
+
+## ADR
+
+## ADRL
+
+## CYC
diff --git a/docs/macro_samples.md b/docs/macro_samples.md
new file mode 100644
index 0000000..9b7d5ef
--- /dev/null
+++ b/docs/macro_samples.md
@@ -0,0 +1,164 @@
+# x65macro.i
+
+This is a file under macros and is intended as an example to look at for understanding macro features, it is not super tested for correctness. This information is included in the header file itself but to ease reading copied here. The macros folder also has more detailed documentation.
+
+## Suffix definition
+
+The letters after the period has the following meanings:
+- b: byte
+- w: word (2 bytes)
+- t: triple (3 bytes)
+- l: long (4 bytes)
+- n: number of bytes in value
+- c: copy result to target
+- i: immediate, for example add a value to the contents of an address
+- x: use the x register for operation as a counter or an offset
+- y: use the y register for operation
+- r: relative; ry=(zp),y
+- a: use the contents of an address for operation (16 bits)
+- s: custom step size (instead of +1 or -1) for loops
+- p: positive
+- m: negative
+- o: use label pool for counter
+
+## operations
+
+The base operations provided by these macros are:
+
+- set: Assign a value to the contents of an address
+- move: Move the contents of an address to another address
+- add: addition
+- sub: subtraction
+- asrm: arithmetic shift right
+- aslm: arithmetic shift left
+- neg: negate a number
+- abs: make a number positive
+- copy: copy memory from one location to another
+- for: iterate between two numbers with optional step size
+- mnop: insert multiple nop at this point
+
+set.b / .w / .t / .l Value, Target
+  - set the contents of an 1-4 byte location to a value
+  - uses accumulator
+
+move.b / .w / .t / .l / .n Src,Trg
+  - copy 1-4 (or n) bytes from Src location to Trg location
+  - uses accumulator
+
+asrm.n Target, Size
+  - shift a signed multi byte number right
+  - uses accumulator
+
+asrm.nx Target, Size
+  - shift a signed multi byte number right offset by the x register
+  - no registers touched
+
+aslm.n Target, Size
+  - shift a multi byte number left
+  - no registers touched
+
+aslm.nx Target, Size
+  - shift a multi byte number left offset by the x register
+  - no registers changed
+
+neg.cn Source, Target, Size
+  - negate and copy a multi byte number
+  - uses accumulator
+
+neg.n Target, Size
+  - negate a number in place
+  - uses accumulator
+
+abs.n Trg, Size
+  - make a number absolute
+  - uses accumulator
+
+neg.nx Trg, Size
+  - negate a number in place offset by the x register
+  - uses accumulator
+
+add.n Address1, Address2, Target, Bytes
+  - add contents of two memory locations into a target lcoation
+  - uses accumulator
+
+sub.n Address1, Address2, Target, Bytes
+  - Target = Address1 - Address2
+  - uses accumulator
+
+add.ni Address, Value, Target, Bytes
+  - add a fixed value to a memory location into a target
+  - uses accumulator
+
+sub.ni Address, Value, Target, Bytes
+  - Target = Address - Value
+  - uses accumulator
+
+add.wi Address, Value, Target
+  - Subtract 16 bit Value from contents of Address and store at Target
+  - uses accumulator
+
+sub.wi Address1, Address2, Target
+  - add contents of two 16 bit addresses into a target 16 bit location
+  - uses accumulator
+
+mnop Count
+  - add Count nops
+
+copy.x Source, Target, Size
+  - copy up to 256 bytes using the x register as a counter
+  - uses accumulator and x register
+
+copy.y Source, Target, Size
+  - copy up to 256 bytes using the y register as a counter
+  - uses accumulator and y register
+
+copy.ry zpSrcPtr,zpTrgPtr,Size
+  - copy a fixed length buffer using relative zp y indexing
+  - size is up to a page, changing Y and A
+
+copy.ry128 zpSrcPtr,zpTrgPtr,Size
+  - copy up to 128 bytes using the y register
+
+copy.o Src,Trg,Size,PoolZP
+  - copy more than 256 bytes using zero page label pool addresses
+  - uses accumulator, x and y register
+
+copy.a Src,Trg,Size
+  - copy more than 256 bytes using absolute indexed in a loop
+  - uses accumulator, x and y register
+
+copy.zp Src,Trg,Size,zpTmp1,zpTmp2
+  - copy more than 256 bytes using two pairs of zero page values
+  - uses accumulator, x and y register
+
+for.x Start, End
+  - iterate using the x register from Start to End, End is not inclusive
+    so to iterate from 31 to 0 use for.x 31, -1
+  - uses x register
+  - end for loop with forend macro
+
+for.y Start, End
+  - same as for.x but with the y register
+  - uses y register
+  - end for loop with forend macro
+
+for.w Start, End, Counter
+  - for loop for 16 bit counter
+  - uses accumulator
+  - end for loop with forend macro
+
+for.ws Start, End, Counter, Step
+  - for loop for 16 bit counter with a step value
+  - uses accumulator
+  - end for loop with forend macro
+
+for.wsp Start, End, Counter, Step {
+  - for (word Counter=start; Counter<end; Counter += Step), Step>0
+  - uses accumulator
+
+for.wsm Start, End, Counter, Step {
+  - for (word Counter=start; Counter<end; Counter += Step), Step<0
+  - uses accumulator
+
+forend
+  - terminates for loops
diff --git a/docs/readme.md b/docs/readme.md
new file mode 100644
index 0000000..b71c3cb
--- /dev/null
+++ b/docs/readme.md
@@ -0,0 +1,48 @@
+# x65 Assembler
+
+x65 is an open source 6502 series assembler that supports object files,
+linking, fixed address assembling and a relocatable executable.
+
+Assemblers have existed for a long time and what they do is well documented,
+x65 tries to accomodate most expectations of syntax from Kick Assembler (a
+Java 6502 assembler) to Merlin (an Apple II assembler).
+
+For debugging, dump_x65 is a tool that will show all content of x65 object
+files, and x65dsasm is a disassembler intended to review the assembled
+result. 
+
+## Noteworthy features:
+
+* Code with sections, object files and linking or single file fixed
+  address, or mix it up with fixed address sections in object files.
+* Assembler listing with cycle counting for code review.
+* Export multiple binaries with a single link operation.
+* C style scoping within '{' and '}' with local and pool labels
+  respecting scopes.
+* Conditional assembly with if/ifdef/else etc.
+* Assembler directives representing a variety of features.
+* Local labels can be defined in a number of ways, such as leading
+  period (.label) or leading at-sign (@label) or terminating
+  dollar sign (label$).
+* String Symbols system allows building user expressions and macros
+  during assembly.
+* Reassignment of symbols and labels by default.
+* No indentation required for instructions, meaning that labels can't
+  be mnemonics, macros or directives.
+* Supporting the syntax of other 6502 assemblers (Merlin syntax
+  requires command line argument, -endm adds support for sources
+  using macro/endmacro and repeat/endrepeat combos rather
+  than scoeps).
+* Apple II GS executable output.
+
+## Command Line Options
+
+See [command_line_options.md]
+
+## Directives
+
+See [directives.md]
+
+## Macro examples
+
+See [macro_samples.md]
\ No newline at end of file
diff --git a/macros/x65macro.i b/macros/x65macro.i
index 49f3d53..f4ab7b6 100644
--- a/macros/x65macro.i
+++ b/macros/x65macro.i
@@ -635,7 +635,7 @@ _ForLoop
 macro for.y Start, End {
   ldx #Start
   if Start < End
-    string _ForEnd = "iny\ncpx #End\nbne _ForLoop"
+    string _ForEnd = "iny\ncpy #End\nbne _ForLoop"
   elif Start > End
   {
     if (-1 == End) & (Start<129)