MegaLZ depacker

[LCD]

Poke 23388 with current Bank
And this is the version which can decompress from other banks to a buffer to main memory:

Code:

' MegaLZ Unpacker by Britlion, Banking by LCD
SUB megaLZDepack(source as uInteger,dest as uInteger,bank as ubyte)
ASM

    LD E,(IX+6)
    LD D,(IX+7)
    di
    ld a,(ix+9)
    ld bc,32765
    out (c),a

;'Z80 depacker for megalz V4 packed files   (C) fyrex^mhm

;' DESCRIPTION:
;'
;' Depacker is fully relocatable, not self-modifying,
;'it's length is 110 bytes starting from DEC40.
;'Register usage: AF,AF',BC,DE,HL. Must be CALL'ed, return is done by RET.
;'Provide extra stack location for store 2 bytes (1 word). Depacker does not
;'disable or enable interrupts, as well as could be interrupted at any time
;'(no f*cking wicked stack usage :).

;' USAGE:
;'
;' - put depacker anywhere you want,
;' - put starting address of packed block in HL,
;' - put location where you want data to be depacked in DE,
;'   (much like LDIR command, but without BC)
;' - make CALL to depacker (DEC40).
;' - enjoy! ;)

;' PRECAUTIONS:
;'
;' Be very careful if packed and depacked blocks coincide somewhere in memory.
;'Here are some advices:
;'
;' 1. put packed block to the highest addresses possible.
;'     Best if last byte of packed block has address #FFFF.
;'
;' 2. Leave some gap between ends of packed and depacked block.
;'     For example, last byte of depacked block at #FF00,
;'     last byte of packed block at #FFFF.
;'
;' 3. Place nonpackable data to the end of block.
;'
;' 4. Always check whether depacking occurs OK and neither corrupts depacked data
;'     nor hangs computer.
;'

;'DEC40

        LD      A,80h
        EX      AF,AF'
MS:     LDI
M0:      LD      BC,2FFh
M1:      EX      AF,AF'
M1X:     ADD     A,A
        JR      NZ,M2
        LD      A,(HL)
        INC     HL
        RLA
M2:      RL      C
        JR      NC,M1X
        EX      AF,AF'
        DJNZ    X2
        LD      A,2
        SRA     C
        JR      C,N1
        INC     A
        INC     C
        JR      Z,N2
        LD      BC,33Fh
        JR      M1

X2:      DJNZ    X3
        SRL     C
        JR      C,MS
        INC     B
        JR      M1
X6:
        ADD     A,C
N2:
        LD      BC,4FFh
        JR      M1
N1:
        INC     C
        JR      NZ,M4
        EX      AF,AF'
        INC     B
N5:      RR      C
        JP     C, END_DEC40
        RL      B
        ADD     A,A
        JR      NZ,N6
        LD      A,(HL)
        INC     HL
        RLA
N6:      JR      NC,N5
        EX      AF,AF'
        ADD     A,B
        LD      B,6
        JR      M1
X3:
        DJNZ    X4
        LD      A,1
        JR      M3
X4:      DJNZ    X5
        INC     C
        JR      NZ,M4
        LD      BC,51Fh
        JR      M1
X5:
        DJNZ    X6
        LD      B,C
M4:      LD      C,(HL)
        INC     HL
M3:      DEC     B
        PUSH    HL
        LD      L,C
        LD      H,B
        ADD     HL,DE
        LD      C,A
        LD      B,0
        LDIR
        POP     HL
        JR      M0
      
      
END_DEC40:
    ld a,(23388)
    ld bc,32765
    out (c),a
    ei
END ASM
END SUB

megaLZDepack (32768,49152)