mirror of
https://github.com/emmanuel-marty/lzsa.git
synced 2024-11-25 10:30:45 +00:00
187 lines
4.7 KiB
NASM
187 lines
4.7 KiB
NASM
;
|
|
; Size-optimized LZSA2 decompressor by spke & uniabis (140 bytes)
|
|
;
|
|
; ver.00 by spke for LZSA 1.0.0 (02-09/06/2019, 145 bytes);
|
|
; ver.01 by spke for LZSA 1.0.5 (24/07/2019, added support for backward decompression);
|
|
; ver.02 by uniabis (30/07/2019, 144(-1) bytes, +3.3% speed and support for Hitachi HD64180);
|
|
; ver.03 by spke for LZSA 1.0.7 (01/08/2019, 140(-4) bytes, -1.4% speed and small re-organization of macros);
|
|
; ver.04 by spke for LZSA 1.1.0 (26/09/2019, removed usage of IY, added full revision history)
|
|
;
|
|
; The data must be compressed using the command line compressor by Emmanuel Marty
|
|
; The compression is done as follows:
|
|
;
|
|
; lzsa.exe -f2 -r <sourcefile> <outfile>
|
|
;
|
|
; where option -r asks for the generation of raw (frame-less) data.
|
|
;
|
|
; The decompression is done in the standard way:
|
|
;
|
|
; ld hl,FirstByteOfCompressedData
|
|
; ld de,FirstByteOfMemoryForDecompressedData
|
|
; call DecompressLZSA2
|
|
;
|
|
; Backward compression is also supported; you can compress files backward using:
|
|
;
|
|
; lzsa.exe -f2 -r -b <sourcefile> <outfile>
|
|
;
|
|
; and decompress the resulting files using:
|
|
;
|
|
; ld hl,LastByteOfCompressedData
|
|
; ld de,LastByteOfMemoryForDecompressedData
|
|
; call DecompressLZSA2
|
|
;
|
|
; (do not forget to uncomment the BACKWARD_DECOMPRESS option in the decompressor).
|
|
;
|
|
; Of course, LZSA2 compression algorithms are (c) 2019 Emmanuel Marty,
|
|
; see https://github.com/emmanuel-marty/lzsa for more information
|
|
;
|
|
; Drop me an email if you have any comments/ideas/suggestions: zxintrospec@gmail.com
|
|
;
|
|
; This software is provided 'as-is', without any express or implied
|
|
; warranty. In no event will the authors be held liable for any damages
|
|
; arising from the use of this software.
|
|
;
|
|
; Permission is granted to anyone to use this software for any purpose,
|
|
; including commercial applications, and to alter it and redistribute it
|
|
; freely, subject to the following restrictions:
|
|
;
|
|
; 1. The origin of this software must not be misrepresented; you must not
|
|
; claim that you wrote the original software. If you use this software
|
|
; in a product, an acknowledgment in the product documentation would be
|
|
; appreciated but is not required.
|
|
; 2. Altered source versions must be plainly marked as such, and must not be
|
|
; misrepresented as being the original software.
|
|
; 3. This notice may not be removed or altered from any source distribution.
|
|
;
|
|
|
|
; DEFINE BACKWARD_DECOMPRESS ; uncomment for data compressed with option -b
|
|
; DEFINE HD64180 ; uncomment for systems using Hitachi HD64180
|
|
|
|
IFNDEF BACKWARD_DECOMPRESS
|
|
|
|
MACRO NEXT_HL
|
|
inc hl
|
|
ENDM
|
|
|
|
MACRO ADD_OFFSET
|
|
ex de,hl : add hl,de
|
|
ENDM
|
|
|
|
MACRO BLOCKCOPY
|
|
ldir
|
|
ENDM
|
|
|
|
ELSE
|
|
|
|
MACRO NEXT_HL
|
|
dec hl
|
|
ENDM
|
|
|
|
MACRO ADD_OFFSET
|
|
push hl : or a : sbc hl,de : pop de ; 11+4+15+10 = 40t / 5 bytes
|
|
ENDM
|
|
|
|
MACRO BLOCKCOPY
|
|
lddr
|
|
ENDM
|
|
|
|
ENDIF
|
|
|
|
IFNDEF HD64180
|
|
|
|
MACRO LD_IX_DE
|
|
ld ixl,e : ld ixh,d
|
|
ENDM
|
|
|
|
MACRO LD_DE_IX
|
|
ld e,ixl : ld d,ixh
|
|
ENDM
|
|
|
|
ELSE
|
|
|
|
MACRO LD_IX_DE
|
|
push de : pop ix
|
|
ENDM
|
|
|
|
MACRO LD_DE_IX
|
|
push ix : pop de
|
|
ENDM
|
|
|
|
ENDIF
|
|
|
|
@DecompressLZSA2:
|
|
xor a : ld b,a : exa : jr ReadToken
|
|
|
|
CASE00x: call ReadNibble
|
|
ld e,a : ld a,c
|
|
cp %00100000 : rl e : jr SaveOffset
|
|
|
|
CASE0xx ld d,#FF : cp %01000000 : jr c,CASE00x
|
|
|
|
CASE01x: cp %01100000 : rl d
|
|
|
|
OffsetReadE: ld e,(hl) : NEXT_HL
|
|
|
|
SaveOffset: LD_IX_DE
|
|
|
|
MatchLen: and %00000111 : add 2 : cp 9 : call z,ExtendedCode
|
|
|
|
CopyMatch: ld c,a
|
|
ex (sp),hl ; BC = len, DE = -offset, HL = dest, SP -> [src]
|
|
ADD_OFFSET ; BC = len, DE = dest, HL = dest+(-offset), SP -> [src]
|
|
BLOCKCOPY ; BC = 0, DE = dest
|
|
pop hl ; HL = src
|
|
|
|
ReadToken: ld a,(hl) : NEXT_HL : push af
|
|
and %00011000 : jr z,NoLiterals
|
|
|
|
rrca : rrca : rrca
|
|
call pe,ExtendedCode
|
|
|
|
ld c,a
|
|
BLOCKCOPY
|
|
|
|
NoLiterals: pop af : push de
|
|
or a : jp p,CASE0xx
|
|
|
|
CASE1xx cp %11000000 : jr nc,CASE11x
|
|
|
|
CASE10x: call ReadNibble
|
|
ld d,a : ld a,c
|
|
cp %10100000 : rl d
|
|
dec d : dec d : DB #CA ; jr OffsetReadE ; #CA is JP Z,.. to skip all commands in CASE110 before jr OffsetReadE
|
|
|
|
CASE110: ld d,(hl) : NEXT_HL : jr OffsetReadE
|
|
|
|
CASE11x cp %11100000 : jr c,CASE110
|
|
|
|
CASE111: LD_DE_IX : jr MatchLen
|
|
|
|
ExtendedCode: call ReadNibble : inc a : jr z,ExtraByte
|
|
sub #F0+1 : add c : ret
|
|
ExtraByte ld a,15 : add c : add (hl) : NEXT_HL : ret nc
|
|
ld a,(hl) : NEXT_HL
|
|
ld b,(hl) : NEXT_HL : ret nz
|
|
pop de : pop de ; RET is not needed, because RET from ReadNibble is sufficient
|
|
|
|
ReadNibble: ld c,a : xor a : exa : ret m
|
|
UpdateNibble ld a,(hl) : or #F0 : exa
|
|
ld a,(hl) : NEXT_HL : or #0F
|
|
rrca : rrca : rrca : rrca : ret
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|