Editing xkas

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xkas (acronym for: cross-knight assembler) is a cross-assembler for the WDC G65816 processor, specifically tailored for use with SFC/SNES programming and translations but also supports GBA Thumb CPU (ARM7TDMI Thumb). The documentation below is for the most recent version of xkas.

## Features
* Supports All 256 Opcodes
* Supports Labels / Sublabels / +/- Labels
* Supports Math
* Supports ASCII-Tables
* Supports Defines
* Supports Macros

## Versions
* xkas v0.06
* xkas v0.06 Unoffical
* xkas v0.08 Unoffical
* xkas v0.12
* xkas v0.14

## Command Line

xkas -o output.bin input.asm [second-input.asm ...]

If the output file exists, xkas will assemble the source file on top of this file. If it does not exist, xkas will create the file. Usage examples:

xkas -o output.bin input.asm
    xkas -o output.bin input1.asm input2.asm
    xkas input1.asm input2.asm -o output.bin

## Commands
### arch type
Select processor architecture. Supported values:

none      - None; uses base commands only
    gba.thumb - GBA THUMB CPU (ARM7TDMI THUMB)
    snes.cpu  - SNES CPU (WDC 65816)

### endian type
Manually specify processor endian. This will affect dw, dl and dd commands. Note that selecting a processor architecture will automatically select endian. This is intended to be used for "arch none" only. Supported values:

lsb - Little endian
    msb - Big endian

### incsrc filename.asm
Include additional source file. Note that this command is infinitely recursive. Eg `file1.asm` can `incsrc file2.asm`, which can `incsrc file3.asm`. Recursion is only limited to available memory. The state will remain unchanged, eg all defines and labels will remain in-tact.

### incbin filename.bin
Insert binary file directly into output.

### org offset
Seek to specified offset. Offset address relativity to output file is based upon the current architecture. Eg if `arch = snes.cpu`, `org` should be an SNES-memory-mapped offset. For `arch = none`, this is a literal offset into the output file.

### base offset
Override internal `org` address when computing eg labels. This is useful for relocatable code and custom address mapping. Usage example:

org $c02000; base $7f0000
    lda #$00
    loop:
      jml loop //will assemble as jml $7f0002; while writing to pc($c02002)

### align modulus
Write `0x00`s until offset is evenly divisible by modulus. Eg if offset is `$8011`, "`align 4`" will write three `0x00`s, aligning offset to a 4-byte boundary; in this case, `$8014`.

### db / dw / dl / dd value [, value, "string", ...]
Simple binary data insertion; these are used to write binary data to the file. These commands additionally support quote-delimited 7-bit ANSI encoded strings.

db - Data byte (8-bits)
    dw - Data word (16-bits)
    dl - Data long (24-bits)
    dd - Data double word (32-bits)

### fill length [, value]
Writes "length" number of bytes to output file. If value is not specified, write value is 0x00.

### fillto offset [, value]
Writes until "offset" is reached. If value is not specified, write value is `0x00`.

### define name "value"
Creates a new define, or overrides a previous define by the same name. Quotes are only needed if space is needed inside the define. Usage example:

define add "clc; adc"
    define health_bonus 32
    {add}.w #{health_bonus} //will assemble as clc; adc.w #32

### define 'char' value
Redefine string table entry. "char" must be exactly one ANSI character in length, and "value" must resolve to an integer. Usage example:

define 'C' $1234 // value can be up to 64-bits in length
    lda.b #'C'       // will assemble as lda.b #$34
    lda.w #'C'       // will assemble as lda.w #$1234
    dw "C"           // will write #$1234 to output

### label:
Creates a new label. A label is used to represent a position in code, and allows one to code without having to constantly update branches and jumps/calls. A label should be able to be used in any opcode, but was specifically added to be used with branches, jumps, and calls. Can start with `_[A-Za-z]`, can contain `_[A-Za-z0-9]`.

### .sublabel:
Creates a new sublabel. A sublabel is used to declare labels within labels that will share its address space only, and can contain the same characters as a label. Must start with ., can contain _[A-Za-z0-9]. Sublabel is automatically prefixed with the most recently specified label. Example:

label:
    .sublabel: // will assemble as label.sublabel

### + / - label:
Creates a nameless label. Will ignore active namespace. + is used to point to a label after the current code position, - is used to point before the current position. Can be redefined at any point in the code. Example:

-; dex; beq +; ...; bra -
    +; rts

### namespace name
Sets the active namespace. When a `label`, `sublabel` or `define` is specified without a namespace prefix, it is automatically prefixed by the active namespace. This defaults to "global". Note that unlike C++ namespaces, this function is not recursive. There is only one namespace level. Example:

namespace global
    label:
    .sublabel:
    define def "0"
    dw label, .sublabel, custom::label, custom::label.sublabel, {def}, {custom::def}
    
    namespace custom
    label:
    .sublabel:
    define def "1"
    dw label, .sublabel, global::label, global::label.sublabel, {def}, {global::def}

### print arg [, arg, "string", ...]
Prints specified message to the terminal. Example:

org $8000
    label1:
    print "label1 offset = ", org //prints "label1 offset = 0x8000"

_Written by byuu August 1st, 2004 - October 19th, 2010_

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