Compiler Syntax

This page includes syntax information specific to the compiler that Minicube64 uses.
Comments
Comments begin with a semicolon (;).  A colon (:) following a label is optional
    lda #$00             ;hi there
label1: jmp label2
label2  beq label1
Numbers and expressions
Hexadecimal numbers begin with '$' or end with 'h'.  Binary numbers begin with '%' or end with 'b'.  Characters and strings are surrounded by single or double quotes.  The characters (' " \) within quotes must be preceded by a backslash (\).
12345
'12345'
$ABCD
0ABCDh
%01010101
01010101b
Supported operators (listed by precedence):
          ( )
 (unary)  + - ~ ! < >
          * / %
          + -
          << >>
          < > <= >=
          = == != <> 
          &
          ^
          |
          &&
          ||
'=' and '<>' are equivalent to C's '==' and '!=' operators. The unary '<' and '>' operators give the lower and upper byte of a 16-bit word (respectively).
All other operators function like their C equivalents.
Labels
Labels are case sensitive. 
The special '$' label holds the current program address. Labels beginning with '@' are local labels. They have limited scope, visible only between non-local labels.  Names of local labels may be reused.
label1:
    @tmp1:
    @tmp2:
label2:
    @tmp1:
    @tmp2:
Labels beginning with one or more '+' or '-' characters are nameless labels, especially useful for forward and reverse branches.
--  ldx #0
 -  lda $2002 ;loop (wait for vblank)
    bne -
 -  lda $2002 ;nameless labels are easy to reuse..
    bne -
​
    cpx #69
    beq +     ;forward branch..
    cpx #96
    beq +here ;use more characters to make more unique
​
    jmp --    ;multiple --'s handy for nested loops
+  ldx #0
+here  nop
Assembler directives 
(in no specific order)
All directives are case insensitive and can also be preceded by a period (.)
​
EQU
For literal string replacement, similar to #define in C.
one EQU 1
plus EQU +
DB one plus one ;DB 1 + 1
​
=

Unlike EQU, statements with '=' are evaluated to a number first. Also unlike EQU, symbols created with '=' can be reused.
i=1
j EQU i+1
k=i+1   ;k=1+1
i=j+1   ;i=i+1+1
i=k+1   ;i=2+1
​
INCLUDE (also INCSRC)
Assemble another source file as if it were part of the current source.
INCLUDE whatever.asm
​
INCBIN (also BIN)
Add the contents of a file to the assembly output.
 moredata: INCBIN whatever.bin
An optional file offset and size can be specified.
INCBIN foo.bin, $400 ;read foo.bin from $400 to EOF
INCBIN foo.bin, $200, $2000 ;read $2000 bytes, starting from $200
​
DB, DW (also BYTE/WORD, DCB/DCW, DC.B/DC.W)
Emit byte(s) or word(s).  Multiple arguments are separated by commas.  Strings can be "shifted" by adding a value to them.
DB $01,$02,$04,$08
DB "ABCDE"+1          ;equivalent to DB "BCDEF"
DB "ABCDE"-"A"+32     ;equivalent to DB 32,33,34,35,36
​
DL, DH
Similar to DB, outputting only the LSB or MSB of a value.
DL a,b,c,d            ;equivalent to DB <a, <b, <c, <d
DH a,b,c,d            ;equivalent to DB >a, >b, >c, >d
​
HEX
Compact way of laying out a table of hex values.  Only raw hex values are allowed, no expressions.  Spaces can be used to separate numbers.
HEX 456789ABCDEF  ;equivalent to DB $45,$67,$89,$AB,$CD,$EF
HEX 0 1 23 4567   ;equivalent to DB $00,$01,$23,$45,$67
​
DSB, DSW (also DS.B/DS.W)
Define storage (bytes or words).  The size argument may be followed by a fill value (default filler is 0).
DSB 4         ;equivalent to DB 0,0,0,0
DSB 8,1       ;equivalent to DB 1,1,1,1,1,1,1,1
DSW 4,$ABCD   ;equivalent to DW $ABCD,$ABCD,$ABCD,$ABCD
​
PAD
Fill memory from the current address to a specified address.  A fill value may also be specified.
PAD $FFFA     ;equivalent to DSB $FFFA-$
PAD $FFFA,$EA ;equivalent to DSB $FFFA-$,$EA
​
ORG
Set the starting address if it hasn't been assigned yet, otherwise ORG functions like PAD.
ORG $E000     ;start assembling at $E000
.
.
.
ORG $FFFA,$80 ;equivalent to PAD $FFFA,$80
​
ALIGN
Fill memory from the current address to an N byte boundary.  A fill value may also be specified.
ALIGN 256,$EA
​
FILLVALUE
Change the default filler for PAD, ALIGN, etc.
FILLVALUE $FF
BASE
Set the program address.  This is useful for relocatable code, multiple code banks, etc.  The same can also be accomplished by assigning the '$' symbol directly (i.e. '$=9999').
oldaddr=$
BASE $6000
stuff:
.
.
.
BASE oldaddr+$-stuff
​
IF / ELSEIF / ELSE / ENDIF
Process a block of code if an expression is true (nonzero).
IF j>0
    DB i/j
ELSE
    DB 0
ENDIF
​
IFDEF / IFNDEF
Process a block of code if a symbol has been defined / not defined.
IFDEF _DEBUG_
.
.
.
ENDIF
​
MACRO / ENDM
MACRO name args...
Define a macro.  Macro arguments are comma separated. Labels defined inside macros are local (visible only to that macro)
MACRO setAXY x,y,z
LDA #x
LDX #y
LDY #z
​
ENDM
​
setAXY $12,$34,$56
;expands to LDA #$12
;           LDX #$34
;           LDY #$56
​
REPT / ENDR
Repeat a block of code a specified number of times. Labels defined inside REPT are local.
i=0
REPT 256
DB i
i=i+1
ENDR
​
ENUM / ENDE
Reassign PC and suppress assembly output.  Useful for defining variables in RAM.
ENUM $200
foo:    db 0
foo2:   db 0
ENDE
​
ERROR
Stop assembly and display a message.
IF x>100
    ERROR "X is out of range :("
ENDIF
​
The information on this page is provided from the asm6f documentation by loopy.
​https://github.com/freem/asm6f/blob/master/readme-original.txt​
Memory Map
Macros and Aliases
Last modified 1yr ago