__         ______ _______
    |__| ______/  __  \\   _  \
    |  |/  ___/>      </  /_\  \
    |  |\___ \/   --   \  \_/   \
/\__|  /____  >______  /\_____  /
\______|    \/       \/       \/

js80 is a library and an assembler for z80 cpu.

Installation

Using NPM:

npm install js80 -g

Binaries for Windows:

1. Download [https://github.com/samsaga2/js80/releases]
2. Add the directory bin to your PATH.

Command line

js80asm help:

  Usage: js80asm [options] <file ...>

  Options:

    -h, --help                     output usage information
    -V, --version                  output the version number
    -o, --output <file>            create binary compiled file (default a.out)
    -I, --include <dir1:dir2:...>  add directories into the search list
    -s, --sym <file>               create sym file

Examples:

js80asm test.asm

js80asm test2.asm -o test2.rom -s test2.sym

js80asm test3.asm -I include:../include2

JS80 API

New instance

var JS80 = require('js80');
var js80 = new JS80();

methods

• asm js80.asm(code) ··Compile assembler code.
• defineLabel js80.defineLabel(label, value) ·· Defines a new label.
• secondPass js80.secondPass() ··Execute the second pass. The compiler evaluates the expressions because labels can be declared later.
• buildImage js80.buildImage() ··Returns an array of bytes with the compiled code.
• saveImage js80.saveImage(fileName) ··Save compiled code to a file.
• saveSymbols js80.saveSymbols(fileName) ··Save symbols to a file (useful for debugging).

Example:

var JS80 = require('js80');
var js80 = new JS80();
js80.asm('xor a');
js80.secondPass();
js80.saveImage('a.out');

Assembler

Inst	Desc
label:	Declares a variable
.label:	Declares a local label
// comment //	Comment code
/* comment */	Comment code
; comment	Comment code
inst1\inst2\···\inst-n	Multipe instructions per line
module	Declares a module
endmodule	Ends module declaration
macro	Declares a macro
endmacro	Ends macro declaration
ifdef	Branch if label is defined
ifndef	Branch if label is not defined
if	Branch if cond is not zero
else	Else branch
endif	Ends branching
repeat	Repeat block of code times
endrepeat	End repeats code block
include "filename"	Include another source file
incbin "filename", ?skip, ?length	Include a binary file
rotate	Rotate macro variable arguments
map	TODO
#	TODO
org *	TODO
defpage , ,	TODO
page	TODO
echo e1, e2, ...	TODO
error "msg"	TODO
db e1, e2, ...	TODO
dw e1, e2, ...	TODO
dw	TODO
equ	TODO
struct	Declares a struct
endstruct	Ends struct declaration

Expressions

Expr	Desc
11001100b, 0b11001100b	binary number
0x1a, 01ah, $1a	hexadecimal number
$	current address
-n	negate a number
i-j	substract two numbers
i+j	sum two numbers
i*j	mult two numbers
i/j	div two numbers
i%j	division module
(i)	group expression
i<<j	shift left
i>>j	shift right
i^j	xor
i|j	or
i&j	and
"str"	string
'i'	char
# nbytes	get map and move it nbytes
@0	macro arguments length
@number	get macro argument (start from 1)
str()	convert identifier to string
i==j	compare two expressions
i!=j	compare two expressions
i<=j	compare two expressions
i>=j	compare two expressions
i<j	compare two expressions
i>j	compare two expressions

Examples

run: ld b,100
.1:  ld a,(hl)
     inc a
     ld (hl),a
     inc hl
     djnz .1
     ret
unuseful:
     jr run.1

      module mod1
util: xor a
      ret
      endmodule

      // no module
main: call mod1.util ; calling a module label
      ret

macro noargs
    xor a
endmacro

macro withargs i, j
    ld a,i+j
endmacro

macro withdefaults i, j:1, k:2
    ld a,i+j+k
endmacro

macro varargs i, 1..*
    repeat @0
        ld a,i+@1
        rotate 1
    endrepeat
endmacro

struct spr
    y   # 1
    x   # 1
    col # 1
    pat # 1
endstruct

ld ix,sprite_data
ld a,(ix+spr.y)
ld b,(ix+spr.x)
ld hl,spr.size

Assembler modules

• bios.asm: MSX 2 Bios functions and variables (bios.WRTVRM, bios.H_KEYI, ...)
• rom16k.asm: MSX 16kb rom setup (start label is the entry point)
• rom32k.asm: MSX 32kb rom setup (start label is the entry point)
• megarom.asm: MSX megarom setup (start label is the entry point)
• extensions.asm: Misc utility macros
• math.asm: Misc math funcs
• debug.asm: OpenMSX debug output