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(same speed)
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introspec 2020-01-02 14:30:00 +00:00 committed by GitHub
parent 3b37a0bb70
commit 9cd9fa5939
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1 changed files with 14 additions and 15 deletions
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29
asm/z80/unlzsa1_fast.asm
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@ -1,5 +1,5 @@
;
; Speed-optimized LZSA1 decompressor by spke & uniabis (111 bytes)
; Speed-optimized LZSA1 decompressor by spke & uniabis (109 bytes)
;
; ver.00 by spke for LZSA 0.5.4 (03-24/04/2019, 134 bytes);
; ver.01 by spke for LZSA 0.5.6 (25/04/2019, 110(-24) bytes, +0.2% speed);
@ -9,7 +9,8 @@
; ver.05 by uniabis (22/08/2019, 107(-2) bytes, same speed);
; ver.06 by spke for LZSA 1.0.7 (27/08/2019, 111(+4) bytes, +2.1% speed);
; ver.07 by spke for LZSA 1.1.0 (25/09/2019, added full revision history);
; ver.08 by spke for LZSA 1.1.2 (22/10/2019, re-organized macros and added an option for unrolled copying of long matches)
; ver.08 by spke for LZSA 1.1.2 (22/10/2019, re-organized macros and added an option for unrolled copying of long matches);
; ver.09 by spke for LZSA 1.2.1 (02/01/2020, 109(-2) bytes, same speed)
;
; The data must be compressed using the command line compressor by Emmanuel Marty
; The compression is done as follows:
@ -102,11 +103,12 @@
@DecompressLZSA1:
ld b,0 : jr ReadToken
NoLiterals: xor (hl)
push de : NEXT_HL : ld e,(hl) : jp m,LongOffset
NoLiterals: xor (hl) : NEXT_HL : jp m,LongOffset
ShortOffset: push de : ld e,(hl) : ld d,#FF
; short matches have length 0+3..14+3
ShortOffset: ld d,#FF : add 3 : cp 15+3 : jr nc,LongerMatch
add 3 : cp 15+3 : jr nc,LongerMatch
; placed here this saves a JP per iteration
CopyMatch: ld c,a
@ -120,19 +122,17 @@ ReadToken: ; first a byte token "O|LLL|MMMM" is read from the stream,
; a length of the match that follows after the literals
ld a,(hl) : and #70 : jr z,NoLiterals
cp #70 : jr z,MoreLiterals ; LLL=7 means 7+ literals...
rrca : rrca : rrca : rrca ; LLL<7 means 0..6 literals...
.test cp #70 : jr z,MoreLiterals ; LLL=7 means 7+ literals...
rrca : rrca : rrca : rrca : ld c,a ; LLL<7 means 0..6 literals...
ld c,a : ld a,(hl)
NEXT_HL : COPYBC
ld a,(hl) : NEXT_HL
COPYBC
; next we read the first byte of the offset
push de : ld e,(hl)
; the top bit of token is set if the offset contains two bytes
and #8F : jp p,ShortOffset
LongOffset: ; read second byte of the offset
NEXT_HL : ld d,(hl)
push de : ld e,(hl) : NEXT_HL : ld d,(hl)
add -128+3 : cp 15+3 : jp c,CopyMatch
IFNDEF UNROLL_LONG_MATCHES
@ -186,13 +186,12 @@ VeryLongMatch: ; the codes are designed to overflow;
ENDIF
MoreLiterals: ; there are three possible situations here
xor (hl) : exa
ld a,7 : NEXT_HL : add (hl) : jr c,ManyLiterals
xor (hl) : NEXT_HL : exa
ld a,7 : add (hl) : jr c,ManyLiterals
CopyLiterals: ld c,a
.UseC NEXT_HL : COPYBC
push de : ld e,(hl)
exa : jp p,ShortOffset : jr LongOffset
ManyLiterals: