Speed optimized version based on the original code by Emmanuel Marty. Reformatted.
Removed (unchanged) V1 decompressor source.
This commit is contained in:
parent
c807773edf
commit
143908043d
@ -1,4 +1,4 @@
|
|||||||
Copyright (c) 2021 Emmanuel Marty
|
Copyright (c) 2023 Emmanuel Marty, Chris Hodges
|
||||||
|
|
||||||
This software is provided 'as-is', without any express or implied warranty. In
|
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
|
no event will the authors be held liable for any damages arising from the use of
|
||||||
|
|||||||
@ -1,75 +0,0 @@
|
|||||||
; unzx0_68000.s - ZX0 decompressor for 68000 - 86 bytes
|
|
||||||
;
|
|
||||||
; in: a0 = start of compressed data
|
|
||||||
; a1 = start of decompression buffer
|
|
||||||
;
|
|
||||||
; Copyright (C) 2021 Emmanuel Marty
|
|
||||||
; ZX0 compression (c) 2021 Einar Saukas, https://github.com/einar-saukas/ZX0
|
|
||||||
;
|
|
||||||
; 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.
|
|
||||||
|
|
||||||
zx0_decompress:
|
|
||||||
movem.l a2/d2,-(sp) ; preserve registers
|
|
||||||
moveq #-128,d1 ; initialize empty bit queue
|
|
||||||
; plus bit to roll into carry
|
|
||||||
moveq #-1,d2 ; initialize rep-offset to 1
|
|
||||||
|
|
||||||
.literals: bsr.s .get_elias ; read number of literals to copy
|
|
||||||
subq.l #1,d0 ; dbf will loop until d0 is -1, not 0
|
|
||||||
.copy_lits: move.b (a0)+,(a1)+ ; copy literal byte
|
|
||||||
dbf d0,.copy_lits ; loop for all literal bytes
|
|
||||||
|
|
||||||
add.b d1,d1 ; read 'match or rep-match' bit
|
|
||||||
bcs.s .get_offset ; if 1: read offset, if 0: rep-match
|
|
||||||
|
|
||||||
.rep_match: bsr.s .get_elias ; read match length (starts at 1)
|
|
||||||
.do_copy: subq.l #1,d0 ; dbf will loop until d0 is -1, not 0
|
|
||||||
.do_copy_offs: move.l a1,a2 ; calculate backreference address
|
|
||||||
add.l d2,a2 ; (dest + negative match offset)
|
|
||||||
.copy_match: move.b (a2)+,(a1)+ ; copy matched byte
|
|
||||||
dbf d0,.copy_match ; loop for all matched bytes
|
|
||||||
|
|
||||||
add.b d1,d1 ; read 'literal or match' bit
|
|
||||||
bcc.s .literals ; if 0: go copy literals
|
|
||||||
|
|
||||||
.get_offset: bsr.s .get_elias ; read high byte of match offset
|
|
||||||
neg.b d0 ; obtain negative offset high byte
|
|
||||||
beq.s .done ; exit if EOD marker
|
|
||||||
move.w d0,d2 ; transfer negative high byte into d2
|
|
||||||
lsl.w #8,d2 ; shift it to make room for low byte
|
|
||||||
|
|
||||||
moveq #1,d0 ; initialize length value to 1
|
|
||||||
move.b (a0)+,d2 ; read low byte of offset + 1 bit of len
|
|
||||||
asr.l #1,d2 ; shift len bit into carry/offset in place
|
|
||||||
bcs.s .do_copy_offs ; if len bit is set, no need for more
|
|
||||||
bsr.s .elias_bt ; read rest of elias-encoded match length
|
|
||||||
bra.s .do_copy_offs ; go copy match
|
|
||||||
|
|
||||||
.get_elias: moveq #1,d0 ; initialize value to 1
|
|
||||||
.elias_loop: add.b d1,d1 ; shift bit queue, high bit into carry
|
|
||||||
bne.s .got_bit ; queue not empty, bits remain
|
|
||||||
move.b (a0)+,d1 ; read 8 new bits
|
|
||||||
addx.b d1,d1 ; shift bit queue, high bit into carry
|
|
||||||
; and shift 1 from carry into bit queue
|
|
||||||
|
|
||||||
.got_bit: bcs.s .got_elias ; done if control bit is 1
|
|
||||||
.elias_bt: add.b d1,d1 ; read data bit
|
|
||||||
addx.l d0,d0 ; shift data bit into value in d0
|
|
||||||
bra.s .elias_loop ; keep reading
|
|
||||||
|
|
||||||
.done: movem.l (sp)+,a2/d2 ; restore preserved registers
|
|
||||||
.got_elias: rts
|
|
||||||
@ -1,4 +1,4 @@
|
|||||||
A fast decompressor for the ZX0 format for 680x0 CPUs.
|
An even faster decompressor for the ZX0 format for 680x0 CPUs.
|
||||||
|
|
||||||
ZX0 by Einar Saukas, a successor to ZX7, reaches compression ratios in the ballpark of Exomizer, without requiring any decompression tables.
|
ZX0 by Einar Saukas, a successor to ZX7, reaches compression ratios in the ballpark of Exomizer, without requiring any decompression tables.
|
||||||
|
|
||||||
|
|||||||
157
unzx0_68000.S
157
unzx0_68000.S
@ -1,9 +1,19 @@
|
|||||||
; unzx0_68000.s - ZX0 decompressor for 68000 - 88 bytes
|
; unzx0_68000.s - ZX0 decompressor for 68000
|
||||||
|
;
|
||||||
|
; platon42: Modified to not preserve registers and to not use long word operations with
|
||||||
|
; unlikely and unsupported block lengths > 64 KB. get_elias inlined for speed and other
|
||||||
|
; optimizations.
|
||||||
;
|
;
|
||||||
; in: a0 = start of compressed data
|
; in: a0 = start of compressed data
|
||||||
; a1 = start of decompression buffer
|
; a1 = start of decompression buffer
|
||||||
;
|
;
|
||||||
|
; out: a0 = end of compressed data
|
||||||
|
; a1 = end of decompression buffer
|
||||||
|
;
|
||||||
|
; trashes: d0-d2/a2
|
||||||
|
;
|
||||||
; Copyright (C) 2021 Emmanuel Marty
|
; Copyright (C) 2021 Emmanuel Marty
|
||||||
|
; Copyright (C) 2023 Emmanuel Marty, Chris Hodges
|
||||||
; ZX0 compression (c) 2021 Einar Saukas, https://github.com/einar-saukas/ZX0
|
; ZX0 compression (c) 2021 Einar Saukas, https://github.com/einar-saukas/ZX0
|
||||||
;
|
;
|
||||||
; This software is provided 'as-is', without any express or implied
|
; This software is provided 'as-is', without any express or implied
|
||||||
@ -23,54 +33,113 @@
|
|||||||
; 3. This notice may not be removed or altered from any source distribution.
|
; 3. This notice may not be removed or altered from any source distribution.
|
||||||
|
|
||||||
zx0_decompress:
|
zx0_decompress:
|
||||||
movem.l a2/d2,-(sp) ; preserve registers
|
moveq.l #-128,d1 ; initialize empty bit queue
|
||||||
moveq #-128,d1 ; initialize empty bit queue
|
; plus bit to roll into carry
|
||||||
; plus bit to roll into carry
|
moveq.l #-1,d2 ; initialize rep-offset to 1
|
||||||
moveq #-1,d2 ; initialize rep-offset to 1
|
bra.s .literals
|
||||||
|
|
||||||
.literals: bsr.s .get_elias ; read number of literals to copy
|
.do_copy_offs2
|
||||||
subq.l #1,d0 ; dbf will loop until d0 is -1, not 0
|
move.b (a1,d2.l),(a1)+
|
||||||
.copy_lits: move.b (a0)+,(a1)+ ; copy literal byte
|
move.b (a1,d2.l),(a1)+
|
||||||
dbf d0,.copy_lits ; loop for all literal bytes
|
|
||||||
|
|
||||||
add.b d1,d1 ; read 'match or rep-match' bit
|
|
||||||
bcs.s .get_offset ; if 1: read offset, if 0: rep-match
|
|
||||||
|
|
||||||
.rep_match: bsr.s .get_elias ; read match length (starts at 1)
|
add.b d1,d1 ; read 'literal or match' bit
|
||||||
.do_copy: subq.l #1,d0 ; dbf will loop until d0 is -1, not 0
|
bcs.s .get_offset ; if 0: go copy literals
|
||||||
.do_copy_offs: move.l a1,a2 ; calculate backreference address
|
|
||||||
add.l d2,a2 ; (dest + negative match offset)
|
|
||||||
.copy_match: move.b (a2)+,(a1)+ ; copy matched byte
|
|
||||||
dbf d0,.copy_match ; loop for all matched bytes
|
|
||||||
|
|
||||||
add.b d1,d1 ; read 'literal or match' bit
|
.literals
|
||||||
bcc.s .literals ; if 0: go copy literals
|
; read number of literals to copy
|
||||||
|
moveq.l #1,d0 ; initialize value to 1
|
||||||
|
.elias_loop1
|
||||||
|
add.b d1,d1 ; shift bit queue, high bit into carry
|
||||||
|
bne.s .got_bit1 ; queue not empty, bits remain
|
||||||
|
move.b (a0)+,d1 ; read 8 new bits
|
||||||
|
addx.b d1,d1 ; shift bit queue, high bit into carry
|
||||||
|
; and shift 1 from carry into bit queue
|
||||||
|
|
||||||
.get_offset: moveq #-2,d0 ; initialize value to $fe
|
.got_bit1
|
||||||
bsr.s .elias_loop ; read high byte of match offset
|
bcs.s .got_elias1 ; done if control bit is 1
|
||||||
addq.b #1,d0 ; obtain negative offset high byte
|
add.b d1,d1 ; read data bit
|
||||||
beq.s .done ; exit if EOD marker
|
addx.w d0,d0 ; shift data bit into value in d0
|
||||||
move.w d0,d2 ; transfer negative high byte into d2
|
bra.s .elias_loop1 ; keep reading
|
||||||
lsl.w #8,d2 ; shift it to make room for low byte
|
|
||||||
|
|
||||||
moveq #1,d0 ; initialize length value to 1
|
.got_elias1
|
||||||
move.b (a0)+,d2 ; read low byte of offset + 1 bit of len
|
subq.w #1,d0 ; dbf will loop until d0 is -1, not 0
|
||||||
asr.l #1,d2 ; shift len bit into carry/offset in place
|
.copy_lits
|
||||||
bcs.s .do_copy_offs ; if len bit is set, no need for more
|
move.b (a0)+,(a1)+ ; copy literal byte
|
||||||
bsr.s .elias_bt ; read rest of elias-encoded match length
|
dbra d0,.copy_lits ; loop for all literal bytes
|
||||||
bra.s .do_copy_offs ; go copy match
|
|
||||||
|
|
||||||
.get_elias: moveq #1,d0 ; initialize value to 1
|
add.b d1,d1 ; read 'match or rep-match' bit
|
||||||
.elias_loop: add.b d1,d1 ; shift bit queue, high bit into carry
|
bcs.s .get_offset ; if 1: read offset, if 0: rep-match
|
||||||
bne.s .got_bit ; queue not empty, bits remain
|
|
||||||
move.b (a0)+,d1 ; read 8 new bits
|
|
||||||
addx.b d1,d1 ; shift bit queue, high bit into carry
|
|
||||||
; and shift 1 from carry into bit queue
|
|
||||||
|
|
||||||
.got_bit: bcs.s .got_elias ; done if control bit is 1
|
.rep_match
|
||||||
.elias_bt: add.b d1,d1 ; read data bit
|
; read match length (starts at 1)
|
||||||
addx.l d0,d0 ; shift data bit into value in d0
|
moveq.l #1,d0 ; initialize value to 1
|
||||||
bra.s .elias_loop ; keep reading
|
.elias_loop2
|
||||||
|
add.b d1,d1 ; shift bit queue, high bit into carry
|
||||||
|
bne.s .got_bit2 ; queue not empty, bits remain
|
||||||
|
move.b (a0)+,d1 ; read 8 new bits
|
||||||
|
addx.b d1,d1 ; shift bit queue, high bit into carry
|
||||||
|
; and shift 1 from carry into bit queue
|
||||||
|
|
||||||
.done: movem.l (sp)+,a2/d2 ; restore preserved registers
|
.got_bit2
|
||||||
.got_elias: rts
|
bcs.s .got_elias2 ; done if control bit is 1
|
||||||
|
add.b d1,d1 ; read data bit
|
||||||
|
addx.w d0,d0 ; shift data bit into value in d0
|
||||||
|
bra.s .elias_loop2 ; keep reading
|
||||||
|
|
||||||
|
.got_elias2
|
||||||
|
subq.w #1,d0 ; dbra will loop until d0 is -1, not 0
|
||||||
|
.do_copy_offs
|
||||||
|
move.l a1,a2 ; calculate backreference address
|
||||||
|
add.l d2,a2 ; (dest + negative match offset)
|
||||||
|
.copy_match
|
||||||
|
move.b (a2)+,(a1)+ ; copy matched byte
|
||||||
|
dbra d0,.copy_match ; loop for all matched bytes
|
||||||
|
|
||||||
|
add.b d1,d1 ; read 'literal or match' bit
|
||||||
|
bcc.s .literals ; if 0: go copy literals
|
||||||
|
|
||||||
|
.get_offset
|
||||||
|
moveq.l #-2,d0 ; initialize value to $fe
|
||||||
|
|
||||||
|
; read high byte of match offset
|
||||||
|
.elias_loop3
|
||||||
|
add.b d1,d1 ; shift bit queue, high bit into carry
|
||||||
|
bne.s .got_bit3 ; queue not empty, bits remain
|
||||||
|
move.b (a0)+,d1 ; read 8 new bits
|
||||||
|
addx.b d1,d1 ; shift bit queue, high bit into carry
|
||||||
|
; and shift 1 from carry into bit queue
|
||||||
|
|
||||||
|
.got_bit3
|
||||||
|
bcs.s .got_elias3 ; done if control bit is 1
|
||||||
|
add.b d1,d1 ; read data bit
|
||||||
|
addx.w d0,d0 ; shift data bit into value in d0
|
||||||
|
bra.s .elias_loop3 ; keep reading
|
||||||
|
|
||||||
|
.got_elias3
|
||||||
|
addq.b #1,d0 ; obtain negative offset high byte
|
||||||
|
beq.s .done ; exit if EOD marker
|
||||||
|
move.b d0,-(sp) ; transfer negative high byte to stack
|
||||||
|
move.w (sp)+,d2 ; shift it to make room for low byte
|
||||||
|
|
||||||
|
move.b (a0)+,d2 ; read low byte of offset + 1 bit of len
|
||||||
|
asr.l #1,d2 ; shift len bit into carry/offset in place
|
||||||
|
bcs.s .do_copy_offs2 ; if len bit is set, no need for more
|
||||||
|
moveq.l #1,d0 ; initialize length value to 1
|
||||||
|
; read rest of elias-encoded match length
|
||||||
|
add.b d1,d1 ; read data bit
|
||||||
|
addx.w d0,d0 ; shift data bit into value in d0
|
||||||
|
|
||||||
|
.elias_loop4
|
||||||
|
add.b d1,d1 ; shift bit queue, high bit into carry
|
||||||
|
bne.s .got_bit4 ; queue not empty, bits remain
|
||||||
|
move.b (a0)+,d1 ; read 8 new bits
|
||||||
|
addx.b d1,d1 ; shift bit queue, high bit into carry
|
||||||
|
; and shift 1 from carry into bit queue
|
||||||
|
|
||||||
|
.got_bit4
|
||||||
|
bcs.s .do_copy_offs ; done if control bit is 1
|
||||||
|
add.b d1,d1 ; read data bit
|
||||||
|
addx.w d0,d0 ; shift data bit into value in d0
|
||||||
|
bra.s .elias_loop4 ; keep reading
|
||||||
|
.done
|
||||||
|
rts
|
||||||
|
|||||||
Loading…
Reference in New Issue
Block a user