acme/docs/AllPOs.txt

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ACME
...the ACME Crossassembler for Multiple Environments
--- pseudo opcodes ---
This is a list of all the pseudo opcodes currently implemented.
Stuff in square brackets is optional, stuff followed by "*" may be
given more than once. This list is not sorted alphabetically, the
pseudo opcodes are grouped together according to their usage.
----------------------------------------------------------------------
Section: How to insert values
----------------------------------------------------------------------
Call: !8 EXPRESSION [, EXPRESSION]*
Purpose: Insert 8-bit values.
Parameters: EXPRESSION: Any formula the value parser accepts.
Aliases: "!08", "!by", "!byte"
Examples: !08 127, symbol, -128 ; output some values
!by 14, $3d, %0110, &304, <*, "c"
!byte 3 - 4, symbol1 XOR symbol2, 2 ^ tz, (3+4)*7
Call: !16 EXPRESSION [, EXPRESSION]*
Purpose: Insert 16-bit values.
Parameters: EXPRESSION: Any formula the value parser accepts.
Aliases: "!wo", "!word"
Examples: !16 65535, symbol, -32768 ; output some values
!wo 14, $4f35, %100101010010110, &36304, *, "c"
!word 3000 - 4, a1 AND a2, 2 ^ tz, (3+4)*70, l1 & .j2
Call: !24 EXPRESSION [, EXPRESSION]*
Purpose: Insert 24-bit values.
Parameters: EXPRESSION: Any formula the value parser accepts.
Examples: !24 16777215, symbol, -8388608, 14, $6a4f35
!24 %10010110100101010010110, &47336304, *, "c"
!24 300000 - 4, a1 AND a2, 2 ^ tz, (3+4)*70, l1 & .j2
Call: !32 EXPRESSION [, EXPRESSION]*
Purpose: Insert 32-bit values.
Parameters: EXPRESSION: Any formula the value parser accepts.
Examples: !32 $7fffffff, symbol, -$80000000, 14, $46a4f35
!32 %1001011010010101001011010010, &4733630435, *, "c"
!32 300000 - 4, a AND a2, 2 ^ tz, (3+4)*70, l1 & .j2
Call: !fill AMOUNT [, VALUE]
Purpose: Fill amount of memory with value.
Parameters: AMOUNT: Any formula the value parser accepts, but it
must be solvable even in the first pass.
VALUE: Any formula the value parser accepts. If
omitted, a default value is used (currently zero).
Aliases: "!fi"
Examples: !fi 256, $ff ; reserve 256 bytes
!fill 2 ; reserve two bytes
Call: !align ANDVALUE, EQUALVALUE [, FILLVALUE]
Purpose: Fill memory until a matching address is reached. ACME
outputs FILLVALUE until "program counter AND ANDVALUE"
equals EQUALVALUE.
Parameters: ANDVALUE: Any formula the value parser accepts, but it
must be solvable even in the first pass.
EQUALVALUE: Any formula the value parser accepts, but
it must be solvable even in the first pass.
FILLVALUE: Any formula the value parser accepts. If it
is omitted, a default value is used (currently 234,
that's the 6502 CPU's NOP command).
Examples: !align 255, 0 ; align to page (256 bytes)
!align 63, 0 ; align to C64 sprite block (64 bytes)
----------------------------------------------------------------------
Section: How to insert text strings
----------------------------------------------------------------------
Call: !convtab KEYWORD [ { BLOCK } ]
or: !convtab FILENAME [ { BLOCK } ]
Purpose: Choose text conversion table.
Parameters: KEYWORD: Name of conversion table. Valid names are:
pet converts to PetSCII
raw doesn't convert at all
scr converts to C64 screencode
FILENAME: File name of conversion table, given in
"..." quoting (load from current directory) or in
<...> quoting (load from library). The file must hold
exactly 256 bytes.
BLOCK: A block of assembler statements
Before encountering this PO, ACME defaults to "raw".
This PO supersedes the now deprecated "!cbm".
Aliases: "!ct"
Examples: !convtab raw
!text "Test" ; outputs $54 $65 $73 $74
!ct pet
!tx "Test" ; outputs $d4 $45 $53 $54
!ct scr {
!tx "Test" ; outputs $54 $05 $13 $14
!ct "my_own_table_file"
!tx "abcdefg" ; whatever... :)
}
!tx "Test" ; outputs $d4 $45 $53 $54 again
Hint: If you don't want to fiddle with a hex editor to create a
conversion table file, try using ACME:
!to "asc2pet.ct", plain ; no load address
* = 0 ; pc = table index
; first create "as-is" table
!for i, 0, 255 {!byte i}
; now exchange upper and lower case characters
* = 65, overlay
!for i, 1, 26 {!byte * + 128}
* = 97, overlay
!for i, 1, 26 {!byte * - 32}
The resulting file can be used as a conversion table to convert to
PetSCII (which is useless, because ACME can do so anyway. But you get
the idea).
Call: !text STRING_VALUE [, STRING_VALUE]*
Purpose: Output the given string(s) using the current
conversion table.
Parameters: STRING_VALUE: Can be either a string given in double
quotes or any formula the value parser accepts.
Please note that formula results won't be converted,
but single characters involved in calculations will.
Aliases: "!tx"
Examples: !text "Loading...", Char_NewLine, "Filename:", 0
!tx "Offset character is ", offset - 1 + 'a', 0
Call: !pet STRING_VALUE [, STRING_VALUE]*
Purpose: Output the given string(s) using the PetSCII
conversion table (This means to exchange the upper-
and lowercase characters; useful for C64 programs).
Parameters: STRING_VALUE: Can be either a string given in double
quotes or any formula the value parser accepts.
Please note that formula results won't be converted,
but single characters involved in calculations will.
Examples: !pet "Loading...", Char_NewLine, "Filename:", 0
!pet "Offset character is ", offset - 1 + 'a', 0
Call: !raw STRING_VALUE [, STRING_VALUE]*
Purpose: Output the given string(s) without any conversion at
all.
Parameters: STRING_VALUE: Can be either a string given in double
quotes or any formula the value parser accepts.
Examples: !raw "Loading...", Char_NewLine, "Filename:", 0
!raw "Offset character is ", offset - 1 + 'a', 0
Call: !scr STRING_VALUE [, STRING_VALUE]*
Purpose: Output the given string(s) using the C64 screen code
conversion table (useful for C64 programs, as you will
have guessed).
Parameters: STRING_VALUE: Can be either a string given in double
quotes or any formula the value parser accepts.
Please note that formula results won't be converted,
but single characters involved in calculations will.
Examples: !scr "Loading...", Char_NewLine, "Filename:", 0
!scr "Offset character is ", offset - 1 + 'a', 0
Call: !scrxor XOR_VALUE, STRING_VALUE [, STRING_VALUE]*
Purpose: Output the given string(s) using the C64 screen code
conversion table and exclusive-OR-ing the results with
the given value (useful for C64 programs when inverse
video is needed, or EBC mode, etc.).
Parameters: XOR_VALUE: Any formula the value parser accepts.
STRING_VALUE: Can be either a string given in double
quotes or any formula the value parser accepts.
Please note that formula results will be neither
converted nor exclusive-OR-d.
Single characters involved in calculations will be
converted, but not exclusive-OR-d.
Examples: !scrxor $80, "Loading..."
!scrxor $a0, "Offset char is ", (offset-1+'a') XOR $a0
----------------------------------------------------------------------
Section: File stuff
----------------------------------------------------------------------
Call: !to FILENAME, FILEFORMAT
Purpose: Define the output file name and file type. If this
opcode isn't used, ACME still fully processes the
source code - as the resulting binary isn't stored,
this only serves to check for errors. Instead of using
this pseudo opcode, you can also use the command line
options "--outfile" and "--format".
Parameters: FILENAME: A file name given in "..." quoting.
FILEFORMAT: Name of file format. Valid names are:
cbm with load address (Commodore format)
plain without load address
apple with load address and length (Apple II)
If FILEFORMAT is omitted, ACME gives a warning and
then defaults to "cbm" (this can be changed using the
command line option "--format").
Examples: !to "eprom.p", plain ; don't add a load address
!to "demo.o", cbm ; add c64-style load address
Call: !source FILENAME
Purpose: Assemble another source code file. After having
processed the new file, ACME continues processing the
old one.
Parameters: FILENAME: A file name given in "..." quoting (load
from current directory) or in <...> quoting (load from
library).
Aliases: "!src"
Examples: !source <6502/std.a> ; Read library file
!src "Macros.a" ; Read file from current dir
Call: !binary FILENAME [, [SIZE] [, [SKIP]]]
Purpose: Insert binary file directly into output file.
Parameters: FILENAME: A file name given in "..." quoting (load
from current directory) or in <...> quoting (load from
library).
SIZE: Any formula the value parser accepts, but it
must be solvable even in the first pass. If SIZE is
given, it is used: If the file is longer, only SIZE
bytes are read; if it is shorter, ACME will use
padding until SIZE is reached. If SIZE is omitted,
ACME will include the file until EOF.
SKIP: Any formula the value parser accepts. If SKIP is
omitted, it defaults to zero. ACME will start loading
the file from file offset SKIP. So C64 coders wanting
to include C64 files without their load addresses
should use a SKIP value of 2.
Aliases: "!bin"
Examples: !binary <Own/menudata.b> ; insert library file
!bin "asc2pet.b", 256, 2 ; insert 256 bytes
; from file offset 2.
!bin "table", 2, 9 ; insert 2 bytes from offset 9
!bin "list",, 9 ; insert from offset 9 to EOF
----------------------------------------------------------------------
Section: Symbols
----------------------------------------------------------------------
Call: !zone [TITLE] [ { BLOCK } ]
Purpose: Switch to new zone of local symbols. Zones can either
be nested or used sequentially.
Parameters: TITLE: May consist of letters and digits. Its only
purpose is to be displayed in error messages, so it'll
be omitted in most cases.
BLOCK: A block of assembler statements
If no block is given, the previous zone is terminated
and the new zone is started.
If a block is given, the old zone continues after the
block.
Aliases: "!zn"
Examples: .backgroundcolor = 0 ; some local symbol
!zone File_IO ; new zone begins here, so
.backgroundcolor = 1 ; this is a different symbol
!zn LinkedList_Init
.backgroundcolor = 2
!zone LinkedList { ; start of nested zone
; imagine some code here...
!zone LinkedList_Init
; imagine some more code here...
!zone LinkedList_Body {
; imagine yet some more code here...
!zone LinkedList_SecondPart
; imagine still some more code here...
}
!zone LinkedList_End
; you know what to imagine here...
}
.backgroundcolor = 3 ; => "Symbol already defined."
Call: !symbollist FILENAME
Purpose: Write a symbol list to the given file after assembly
is finished. The list will contain all global symbols.
This table could be loaded during another assembly
session using the "!source" pseudo opcode.
Parameters: FILENAME: A file name given in "..." quoting.
Aliases: "!sl"
Examples: !sl "Symbols.a" ; produce symbol list after assembly
!sl "global" ; produce symbol list after assembly
----------------------------------------------------------------------
Section: Flow control
----------------------------------------------------------------------
Call: !if CONDITION { BLOCK } [ else { BLOCK } ]
Purpose: Conditional assembly. If the given condition is true,
the first block of statements will be parsed;
if it isn't, the second block will be parsed instead
(if present).
Parameters: CONDITION: Any formula the value parser accepts, but
it must be solvable even in the first pass.
BLOCK: A block of assembler statements.
Examples: !text "Black", 0 ; Choose wording according to
!if country = uk { ; content of "country" symbol.
!text "Grey"
} else {
!text "Gray"
}
!byte 0
!text "White", 0
; Insert debug commands if symbol "debug" is not zero:
!if debug { lda #"z":jsr char_output }
Call: !ifdef SYMBOL { BLOCK } [ else { BLOCK } ]
or: !ifdef SYMBOL STATEMENT
Call: !ifndef SYMBOL { BLOCK } [ else { BLOCK } ]
or: !ifndef SYMBOL STATEMENT
Purpose: Conditional assembly, depending on whether a symbol is
already defined or not.
With "ifdef", if the symbol is defined, the first
block of statements will be parsed; if it isn't, the
second block will be parsed instead (if present).
With "ifndef", it's the other way around: If the
symbol isn't defined, the first block of statements
will be parsed; if it is defined, the second block
will be parsed instead (if present).
CAUTION: These opcodes were added to speed up parsing
of library files (see example below). They can be used
to tell passes apart, therefore only use them in your
own files if you're sure you *really* know what you
are doing - using them in the wrong way will result in
loads of error messages.
Parameters: SYMBOL: Any valid symbol name.
BLOCK: A block of assembler statements.
STATEMENT: Any assembler statement.
Examples: ; this was taken from <6502/std.a>:
!ifdef Lib_6502_std_a !eof ; in later passes,
Lib_6502_std_a = 1 ; skip this file.
; During the first pass, the symbol is not defined,
; therefore the file will get parsed. During all
; further passes, the symbol is already defined,
; therefore the file will be skipped.
; if the following code gets included several times,
; only assemble it at the first location:
!ifndef my_label {my_label} ; only define if undefined
!if * = my_label {
; imagine some code here...
; this block will only be assembled at the
; first location where it is included. all
; further instances will be skipped.
}
Call: !for SYMBOL, START, END { BLOCK }
Purpose: Looping assembly. The block of statements will be
parsed a fixed number of times, as specified by the
values of START and END. For a more flexible
possibility, have a look at "!do" below.
Parameters: SYMBOL: Any valid symbol name.
START: Any formula the value parser accepts, but it
must be solvable even in the first pass. SYMBOL will
have this value during the first loop cycle.
END: Any formula the value parser accepts, but it must
be solvable even in the first pass. SYMBOL will have
this value during the last loop cycle.
BLOCK: A block of assembler statements.
If START or END are floats, they will be converted to
integers (never use floats for loop counters). If
START is less than or equal to END, SYMBOL will get
incremented at the end of each cycle; if START is
greater than END, SYMBOL will get decremented at the
end of each cycle. So after leaving the loop, SYMBOL
will have an "illegal" value (END + 1 if counting up,
END - 1 if counting down).
Please note that it is impossible to change the number
of loop cycles "inside" the loop by fiddling with the
counter using the "!set" pseudo opcode: The "!for"
routine keeps its own copy of the counter value and
only sets the symbol value, it never reads it back.
This was done to eliminate a possibility to hang ACME.
Examples:
int2BCD ; conversion table: integer to BCD
!for Outer, 0, 9 {
!for Inner, 0, 9 {
!byte (Outer << 4) OR Inner
}
}
!fill 156, $ff ; values above 99 give 255 (invalid)
BCD2int ; conversion table: BCD to integer
!for Outer, 0, 9 {
!for Inner, 0, 9 {
!byte 10 * Outer + Inner
}
!fill 6, $ff ; invalid BCD values give 255
}
!fill 96, $ff ; invalid BCD values give 255
quickclear ; generate speedcode to clear C64 screen
lda #' '
!for i, 0, 999 {
sta $0400 + i
}
Miscellaneous: The old syntax ("!for SYMBOL, END { BLOCK }" where
START was always implied to be 1) is still fully
supported, but gives a warning to get people to change
to the new syntax. You can disable this warning using
the "-Wno-old-for" switch, but then you will get
warnings for using the *new* syntax.
When migrating your sources, bear in mind that it is
no longer possible to skip the block completely by
specifying a loop count of zero.
Also note that with the new algorithm, SYMBOL has a
different value after the block than during the last
loop cycle, while the old algorithm kept that last
value.
Call: !set SYMBOL = VALUE
Purpose: Assign given value to symbol even if the symbol
already has a different value. Needed for loop
counters when using "!do", for example. Only use this
opcode for something else if you're sure you *really*
know what you are doing... :)
Parameters: SYMBOL: Any valid symbol name.
VALUE: Any formula the value parser accepts.
Example: see "!do" below
Call: !do [KEYWORD CONDITION] { BLOCK } [KEYWORD CONDITION]
Purpose: Looping assembly. The block of statements can be
parsed several times, depending on the given
condition(s).
Conditions may be placed before or after the block (or
even at both places), they are then parsed in every
repetition before or after the block respectively. If
there is a condition before the block and it isn't
met when first checked, the block will be skipped.
Parameters: KEYWORD: Either "until" or "while" (without quotes).
CONDITION: Any formula the value parser accepts, but
it must be solvable even in the first pass.
BLOCK: A block of assembler statements.
Examples: ; a loop with conditions at both start and end
!set a = 0 ; init loop counter
!do while loop_flag = TRUE {
lda #a
sta label + a
!set a = a + 1
} until a > 6
; a loop with a condition at the start
!do while * < $c000 { nop }
; a loop with a condition at the end
!do { !wo * + base } while * < base + 345
; a never ending loop - this will cause an error
!do while 3 < 4 { nop } until 3 = 4
; an empty loop - this will hang ACME
!do until 3 = 4 { } while 3 < 4
Call: !endoffile
Purpose: Stop processing the current source file. Using this
pseudo opcode you can add explanatory text inside your
source file without having to comment out every single
line of it.
Aliases: "!eof"
Example: rts ; some assembler mnemonic
!eof
Though this text isn't preceded by a semicolon, it is
treated as if it were a comment. In fact, ACME doesn't
even parse this anymore - the file gets closed when
"!eof" is reached.
Call: !warn STRING_VALUE [, STRING_VALUE]*
Purpose: Show a warning during assembly.
Parameters: STRING_VALUE: Can be either a string given in double
quotes or any formula the value parser accepts.
Numbers will be output in decimal _and_ hex format.
Example: !if * > $a000 {
!warn "Program reached ROM: ", * - $a000, " bytes overlap."
}
Call: !error STRING_VALUE [, STRING_VALUE]*
Purpose: Generate an error during assembly (therefore, no
output file will be generated).
Parameters: STRING_VALUE: Can be either a string given in double
quotes or any formula the value parser accepts.
Numbers will be output in decimal _and_ hex format.
Example: rts ; end of some function
start !source "colors.a"
end !if end - start > 256 {
!error "Color strings are ", end - start - 256, " bytes too long."
}
Call: !serious STRING_VALUE [, STRING_VALUE]*
Purpose: Generate a serious error, immediately stopping
assembly.
Parameters: STRING_VALUE: Can be either a string given in double
quotes or any formula the value parser accepts.
Numbers will be output in decimal _and_ hex format.
Example: !source "part1.a" ; sets part1_version
!source "part2.a" ; sets part2_version
!if part1_version != part2_version {
!serious "part1.a and part2.a don't match!"
}
----------------------------------------------------------------------
Section: Macro usage
----------------------------------------------------------------------
Call: !macro TITLE [[~]SYMBOL [, [~]SYMBOL]*] { BLOCK }
Purpose: Define a macro.
Parameters: TITLE: The macro's desired name (same rules as for
symbol names). If the title's first character is a dot
("."), the macro will be local (though why anyone
could want this is beyond me).
SYMBOL: The desired name for the parameter value at
call time. Normally, these parameter symbols should be
local (first character a dot), as different macro
calls will almost for sure have different parameter
values.
If you prefix SYMBOL with a '~' character, it will be
called by reference, not by value: Changing the value
inside the macro will result in the "outer" symbol to
be changed as well.
BLOCK: A block of assembler statements.
Examples: ; far branch, as defined in <6502/std.a>
!macro bne .target {
beq * + 5
jmp .target
}
; increase 16-bit counters
!macro dinc .target {
inc .target
bne + ; "bne * + 5" would not work in zp
inc .target + 1
+
}
; Yes, anonymous label references can be used with
; macros (unlike several other assemblers). That's
; because ACME's macros are implemented more like
; real functions.
; load A and X
!macro ldax .target {
lda .target
ldx .target + 1
}
; store A and X
!macro stax .target {
sta .target
stx .target + 1
}
; use call-by-reference for return value
!macro reserve ~.address, .amount {
.address = external_pc
!set external_pc = external_pc + .amount
}
; define a pixel row of a C64 hardware sprite
!macro SpriteLine .v {
!by .v >> 16, (.v >> 8) & 255, .v & 255
}
Call: +TITLE [ARGUMENT [, ARGUMENT]*]
Purpose: Call a macro, using the given parameter values.
Parameters: TITLE: The macro's name as given in its definition.
ARGUMENT: This is either any formula the value parser
accepts, or (new in release 0.86) a '~' character
followed by a symbol name. The '~'-prefix indicates
call-by-reference semantics, which means that when the
macro changes the symbol's value, the caller's
symbol's value will change as well.
Examples: inc label
bne mark ; "near" branch
inc label2
+bne mark2 ; "far" branch
inc $fa ; increase 8-bit counter
+dinc $fb ; increase 16-bit counter
ldy label ; get byte
+ldax label2 ; get two bytes
; using macro calls in a macro definition
!macro cp16 .source, .target {
+ldax .source
+stax .target
}
; use call-by-reference for return value
!set external_pc = $0400
+reserve ~.line_buffer, 80
+reserve ~.in_buffer, 256
+reserve ~.out_buffer, 256
+reserve ~.byte_var, 1
; define a C64 hardware sprite
; 765432107654321076543210
+SpriteLine %........................
+SpriteLine %.#......................
+SpriteLine %.##.....................
+SpriteLine %.###....................
+SpriteLine %.####...................
+SpriteLine %.#####..................
+SpriteLine %.######.................
+SpriteLine %.#######................
+SpriteLine %.########...............
+SpriteLine %.#########..............
+SpriteLine %.########...............
+SpriteLine %.######.................
+SpriteLine %.######.................
+SpriteLine %.##..##.................
+SpriteLine %.#....##................
+SpriteLine %......##................
+SpriteLine %.......##...............
+SpriteLine %.......##...............
+SpriteLine %........##..............
+SpriteLine %........##..............
+SpriteLine %........................
!byte 0 ; pad to 64-byte block
Since release 0.86, different macros are allowed to have the same name
as long as their parameter lists differ in size (number of arguments)
or type (call-by-value vs. call-by-reference). So
!macro process_bytes b1, b2 {...whatever...}
!macro process_bytes b1, b2, b3 {...whatever...}
!macro process_bytes b1, b2, ~b3 {...whatever...}
can *all* be used at the same time without any name clash.
----------------------------------------------------------------------
Section: Segment assembly
----------------------------------------------------------------------
Call: * = EXPRESSION [, MODIFIER]*
Purpose: Set program counter to given value and start new
segment. This opcode must be given at least once
(or the command line option "--setpc" must be used).
If segments overlap each other, warnings will be
issued. Because some people do this overlapping
on purpose, the warnings can be suppressed using
modifier keywords.
Future versions of ACME may issue errors instead of
warnings.
Parameters: EXPRESSION: Any formula the value parser accepts, but
it must be solvable even in the first pass.
MODIFIER: "overlay" or "invisible" (without quotes):
"overlay" suppresses the warning "Segment starts
inside another one, overwriting it".
"invisible" makes the new segment invisible, so that
_other_ segments will never raise the warning "Segment
reached another one, overwriting it".
Examples: !to "TinyDemo", cbm ; define output file + format
* = $0801 ; start at C64 BASIC start
!src "basicmacros.a" ; include macro definitions
+basic_header ; call program header macro
!src "main.a" ; include main program
* = $1000 ; jump to new segment
!bin "music.b" ; load music to $1000
* = $8000 ; jump to new segment
!bin "pic.b" ; load graphics to $8000
* = $8010, overlay, invisible ; go back and patch
; the graphics, suppressing warnings
; After assembly, ACME will save everything from $0801
; up to the highest address written to. The resulting
; file will contain some big unused areas (zero'd),
; but demos will get compressed anyway... :)
Call: !initmem EXPRESSION
Purpose: Define "unchanged" memory. ACME will fill its output
buffer completely with the given value before storing
the assembled code. So gaps between segments will
contain the desired byte when writing the output file.
Instead of using this pseudo opcode, you can also use
the "--initmem" command line option. If neither is
used, the buffer is cleared.
Parameters: EXPRESSION: Any formula the value parser accepts, but
it must be solvable even in the first pass (because
this opcode will be ignored in all later passes).
Examples: !to "TinyDemo", cbm ; define output file + format
!initmem $ea ; default memory content $ea.
* = $0801 ; start at C64 BASIC start
!src "basicmacros.a" ; include macro definitions
+basic_header ; call program header macro
!src "main.a" ; include main program
* = $1000 ; jump to new segment
!bin "music.b" ; load music to $1000
* = $8000 ; jump to new segment
!bin "pic.b" ; load graphics to $8000
* = $8010, overlay, invisible ; go back and patch
; the graphics, suppressing warnings
; This is the same example as before, but now the big
; unused areas will contain the value $ea instead of
; zero.
!initmem $ff ; Default memory content is now $ff.
; Useful if you want to store your code in an EPROM.
----------------------------------------------------------------------
Section: Offset assembly
----------------------------------------------------------------------
Call: !pseudopc EXPRESSION { BLOCK }
Purpose: Assemble code as if the program counter had the given
value, effectively producing a program that has to be
copied to a different address space before being run.
After having processed the block of statements with
the new program counter, the updated (!) old program
counter is used again.
Thanks to the block syntax, offset assembly can now be
nested. Then the old program counter would not
necessarily be the *real* program counter, but could
be a pseudopc as well. ;)
Parameters: EXPRESSION: Any formula the value parser accepts, but
it must be solvable even in the first pass.
BLOCK: A block of assembler statements.
Examples: ldx #.shifted_end - .shifted_start
- lda .shifted_start - 1, x
sta .target - 1, x
dex
bne -
jmp .target
.shifted_start
!pseudopc $0400 {
.target ; imagine some code here...
; it should be copied to $0400 and executed *there*
}
.shifted_end
----------------------------------------------------------------------
Section: CPU support pseudo opcodes (especially 65816 support)
----------------------------------------------------------------------
Call: !cpu KEYWORD [ { BLOCK } ]
Purpose: Select the processor to produce code for. If this PO
isn't used, ACME defaults to the 6502 CPU (or to the
one selected by the "--cpu" command line option).
ACME will give errors if you try to assemble commands
the chosen CPU does not have. You can change the
chosen CPU at any time. When used with block syntax,
the previously chosen CPU value is restored
afterwards.
Parameters: KEYWORD: Currently valid keywords are:
6502 allows official mnemonics and addressing modes
6510 adds mnemonics for some undocumented opcodes
(but includes all the official 6502 stuff)
c64dtv2 allows DTV2 extensions (includes 6510)
65c02 allows official 65c02 stuff (includes 6502)
65816 allows official 65816 stuff (includes 65c02)
BLOCK: A block of assembler statements.
Examples: !if cputype = $65c02 {
!cpu 65c02 { ; temporarily allow 65c02 stuff
stz .todelete
}
} else {
pha
lda #0
sta .todelete
pla
}
rts
!cpu 65816 ; allow 65816 commands from here on
Call: !al [ { BLOCK } ]
Purpose: Assume long (16 bits) accumulator. Only allowed when
producing code for the 65816 CPU. When used with block
syntax, the previous configuration is restored
afterwards.
Call: !as [ { BLOCK } ]
Purpose: Assume short (8 bits) accumulator. Only needed when
producing code for the 65816 CPU. When used with block
syntax, the previous configuration is restored
afterwards. Short accumulator is the default in every
pass.
Call: !rl [ { BLOCK } ]
Purpose: Assume long (16 bits) index registers. Only allowed
when producing code for the 65816 CPU. When used with
block syntax, the previous configuration is restored
afterwards.
Call: !rs [ { BLOCK } ]
Purpose: Assume short (8 bits) index registers. Only needed
when producing code for the 65816 CPU. When used with
block syntax, the previous configuration is restored
afterwards. Short registers are the default in every
pass.
----------------------------------------------------------------------
Section: Type system
----------------------------------------------------------------------
Call: !address [ { BLOCK } ]
or: !address SYMBOL = VALUE
Purpose: Mark a block or a statement as "explicitly defined
symbols are holding addresses".
Parameters: BLOCK: A block of assembler statements
Everything inside the block will be parsed as usual,
but explicitly defined symbols will be marked as
referencing memory.
If no block is given, only the current statement will
be affected, which should then be an explicit symbol
definition.
Aliases: "!addr"
Examples: !addr k_chrout = $ffd2 ; this is an address
CLEAR = 147 ; but this is not
!addr {
; these are addresses:
sid_v1_control = $d404
sid_v2_control = $d40b
sid_v3_control = $d412
}
; these are not:
sid_VOICECONTROL_NOISE = %#.......
sid_VOICECONTROL_RECTANGLE = %.#......
sid_VOICECONTROL_SAWTOOTH = %..#.....
sid_VOICECONTROL_TRIANGLE = %...#....
----------------------------------------------------------------------
Section: Obsolete pseudo opcodes (they will throw errors if used)
----------------------------------------------------------------------
Call: !cbm
Purpose: Use PetSCII as the text conversion table. Now
superseded by the "!convtab" pseudo opcode.
Old usage: !cbm ; gives "use !ct pet instead" error
Now use: !convtab pet ; does the same without error
Call: !subzone [TITLE] { BLOCK }
Purpose: Allows nesting of zones. Now superseded by "!zone"
because that allows nesting as well.
Parameters: TITLE: May consist of letters and digits.
BLOCK: A block of assembler statements.
Aliases: "!sz"
Old usage: !subzone graphics {
!source "graphics.a"
}
Now use: !zone graphics {
!source "graphics.a"
}
Call: !realpc
Purpose: Restore the program counter to its real value,
therefore finishing offset assembly. Because
"!pseudopc" now knows block syntax and can be nested,
there's no reason to use "!realpc" any more.
Old usage: !pseudopc $0400
; imagine some code here...
!realpc
Now use: !pseudopc $0400 {
; imagine some code here...
}