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| author | Juan J. Martinez <jjm@usebox.net> | 2020-12-30 19:07:31 +0000 |
|---|---|---|
| committer | Juan J. Martinez <jjm@usebox.net> | 2020-12-30 19:23:41 +0000 |
| commit | 2682bc5d1d864341aaeb42a449db73c3ecd16d70 (patch) | |
| tree | 9116764364b4ee0ce7f6037305077807b57776de /tools/rasm/decrunch/deexo.asm | |
| download | ubox-msx-lib-2682bc5d1d864341aaeb42a449db73c3ecd16d70.tar.gz ubox-msx-lib-2682bc5d1d864341aaeb42a449db73c3ecd16d70.zip | |
Initial import1.0
Diffstat (limited to 'tools/rasm/decrunch/deexo.asm')
| -rw-r--r-- | tools/rasm/decrunch/deexo.asm | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/tools/rasm/decrunch/deexo.asm b/tools/rasm/decrunch/deexo.asm new file mode 100644 index 0000000..6a4a7ac --- /dev/null +++ b/tools/rasm/decrunch/deexo.asm @@ -0,0 +1,118 @@ +;Exomizer 2 Z80 decoder
+; by Metalbrain
+;
+; optimized by Antonio Villena and Urusergi (169 bytes)
+;
+; compression algorithm by Magnus Lind
+
+;input: hl=compressed data start
+; de=uncompressed destination start
+;
+; you may change exo_mapbasebits to point to any free buffer
+;
+;ATTENTION!
+;A huge speed boost (around 14%) can be gained at the cost of only 5 bytes.
+;If you want this, replace all instances of "call exo_getbit" with "srl a" followed by
+;"call z,exo_getbit", and remove the first two instructions in exo_getbit routine.
+
+Macro Mizoumizeur
+
+@deexo: ld iy, @exo_mapbasebits+11
+ ld a, (hl)
+ inc hl
+ ld b, 52
+ push de
+ cp a
+@exo_initbits: ld c, 16
+ jr nz, @exo_get4bits
+ ld ixl, c
+ ld de, 1 ;DE=b2
+@exo_get4bits: srl a: call z, @exo_getbit ;get one bit
+ rl c
+ jr nc, @exo_get4bits
+ inc c
+ push hl
+ ld hl, 1
+ ld (iy+41), c ;bits[i]=b1 (and opcode 41 == add hl,hl)
+@exo_setbit: dec c
+ jr nz, @exo_setbit-1 ;jump to add hl,hl instruction
+ ld (iy-11), e
+ ld (iy+93), d ;base[i]=b2
+ add hl, de
+ ex de, hl
+ inc iy
+ pop hl
+ dec ixl
+ djnz @exo_initbits
+ pop de
+ jr @exo_mainloop
+@exo_literalrun: ld e, c ;DE=1
+@exo_getbits: dec b
+ ret z
+@exo_getbits1: srl a : call z,@exo_getbit
+ rl e
+ rl d
+ jr nc, @exo_getbits
+ ld b, d
+ ld c, e
+ pop de
+@exo_literalcopy:ldir
+@exo_mainloop: inc c
+ srl a : call z,@exo_getbit ;literal?
+ jr c, @exo_literalcopy
+ ld c, 239
+@exo_getindex: srl a : call z,@exo_getbit
+ inc c
+ jr nc,@exo_getindex
+ ret z
+ push de
+ ld d, b
+ jp p, @exo_literalrun
+ ld iy, @exo_mapbasebits-229
+ call @exo_getpair
+ push de
+ rlc d
+ jr nz, @exo_dontgo
+ dec e
+ ld bc, 512+32 ;2 bits, 48 offset
+ jr z, @exo_goforit
+ dec e ;2?
+@exo_dontgo: ld bc, 1024+16 ;4 bits, 32 offset
+ jr z, @exo_goforit
+ ld de, 0
+ ld c, d ;16 offset
+@exo_goforit: call @exo_getbits1
+ ld iy, @exo_mapbasebits+27
+ add iy, de
+ call @exo_getpair
+ pop bc
+ ex (sp), hl
+ push hl
+ sbc hl, de
+ pop de
+ ldir
+ pop hl
+ jr @exo_mainloop ;Next!
+
+@exo_getpair: add iy, bc
+ ld e, d
+ ld b, (iy+41)
+ call @exo_getbits
+ ex de, hl
+ ld c, (iy-11)
+ ld b, (iy+93)
+ add hl, bc ;Always clear C flag
+ ex de, hl
+ ret
+
+@exo_getbit: ; srl a
+ ;ret nz
+ ld a, (hl)
+ inc hl
+ rra
+ ret
+
+@exo_mapbasebits: defs 156 ;tables for bits, baseL, baseH
+
+Mend
+
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