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;Exomizer 2 Z80 decoder
;Copyright (C) 2008-2016 by Jaime Tejedor Gomez (Metalbrain)
;
;Optimized by Antonio Villena and Urusergi (169 bytes)
;
;Compression algorithm by Magnus Lind
;
; This depacker is free software; you can redistribute it and/or
; modify it under the terms of the GNU Lesser General Public
; License as published by the Free Software Foundation; either
; version 2.1 of the License, or (at your option) any later version.
;
; This library is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
; Lesser General Public License for more details.
;
; You should have received a copy of the GNU Lesser General Public
; License along with this library; if not, write to the Free Software
; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;
;
;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.
; ---------------------------
; modified by Megachur in 2018
; ---------------------------
; hl -> compressed data start
; de -> uncompressed destination start
; ---------------------------
;EXO_BACKWARD equ 1
ENABLE_MEXO_GETBIT equ 1
list:EXOMIZER_ADDRESS:nolist
; ---------------------------
MACRO MEXO_GETBIT
srl a
jr nz,@1
ld a,(hl)
IFDEF EXO_BACKWARD
dec hl
ELSE
inc hl
ENDIF
rra
@1
ENDM
deexo:
ld iy,exo_mapbasebits+11
ld a,(hl)
IFDEF EXO_BACKWARD
dec hl
ELSE
inc hl
ENDIF
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:
IFDEF ENABLE_MEXO_GETBIT
MEXO_GETBIT
ELSE
srl a:call z,exo_getbit ;call exo_getbit ;get one bit
ENDIF
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:
IFDEF ENABLE_MEXO_GETBIT
MEXO_GETBIT
ELSE
srl a:call z,exo_getbit ;call exo_getbit
ENDIF
rl e
rl d
jr nc,exo_getbits
ld b,d
ld c,e
pop de
exo_literalcopy:
IFDEF EXO_BACKWARD
lddr
ELSE
ldir
ENDIF
exo_mainloop:
inc c
IFDEF ENABLE_MEXO_GETBIT
MEXO_GETBIT
ELSE
srl a:call z,exo_getbit ;call exo_getbit ;literal?
ENDIF
jr c,exo_literalcopy
ld c,239
exo_getindex:
IFDEF ENABLE_MEXO_GETBIT
MEXO_GETBIT
ELSE
srl a:call z,exo_getbit ;call exo_getbit
ENDIF
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
IFDEF EXO_BACKWARD
ex de,hl
add hl,de
lddr
ELSE
push hl
sbc hl,de
pop de
ldir
ENDIF
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
IFDEF ENABLE_MEXO_GETBIT
ELSE
exo_getbit:
; srl a
; ret nz
ld a,(hl)
inc hl
rra
ret
ENDIF
exo_mapbasebits:
ds 156,#00 ;tables for bits,baseL,baseH
; ---------------------------
list:EXOMIZER_ADDRESS_LENGTH equ $-EXOMIZER_ADDRESS:nolist
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