diff --git a/z80_unpacker/example/example.asm b/z80_unpacker/example/example.asm index 80fd790..e3e6570 100644 --- a/z80_unpacker/example/example.asm +++ b/z80_unpacker/example/example.asm @@ -3,7 +3,8 @@ DEVICE ZXSPECTRUM48,$8FFF ORG $9000 -compressed_scr_files: ; border color byte + upkr-packed .scr file + ;; forward example data +compressed_scr_files.fwd: ; border color byte + upkr-packed .scr file DB 1 INCBIN "screens/Grongy - ZX Spectrum (2022).scr.upk" DB 7 @@ -13,37 +14,87 @@ compressed_scr_files: ; border color byte + upkr-packed .scr file DB 6 INCBIN "screens/diver - Back to Bjork (2015).scr.upk" .e: + ;; backward example data (unpacker goes from the end of the data!) +compressed_scr_files.rwd.e: EQU $-1 ; the final IX will point one byte ahead of "$" here + INCBIN "screens.reversed/diver - Back to Bjork (2015).scr.upk" + DB 6 + INCBIN "screens.reversed/diver - Mercenary 4. The Heaven's Devil (2014) (Forever 2014 Olympic Edition, 1).scr.upk" + DB 0 + INCBIN "screens.reversed/Schafft - Poison (2017).scr.upk" + DB 7 + INCBIN "screens.reversed/Grongy - ZX Spectrum (2022).scr.upk" +compressed_scr_files.rwd: ; border color byte + upkr-packed .scr file (backward) + DB 1 start: di ; OPT --zxnext -; nextreg 7,3 ; ZX Next: switch to 28Mhz - ld ix,compressed_scr_files -.slideshow_loop +; nextreg 7,3 ; ZX Next: switch to 28Mhz + + ;;; FORWARD packed/unpacked data demo + ld ix,compressed_scr_files.fwd +.slideshow_loop.fwd: ; set BORDER for next image - ldi a,(ix) ; fake: ld a,(ix) : inc ix + ld a,(ix) + inc ix out (254),a ; call unpack of next image directly into VRAM - ld de,$4000 ; target VRAM + ld de,$4000 ; target VRAM exx ; IX = packed data, DE' = destination ($4000) ; returned IX will point right after the packed data - call upkr.unpack + call fwd.upkr.unpack ; do some busy loop with CPU to delay between images + call delay + ; check if all images were displayed, loop around from first one then + ld a,ixl + cp low compressed_scr_files.fwd.e + jr nz,.slideshow_loop.fwd + + ;;; BACKWARD packed/unpacked data demo + ld ix,compressed_scr_files.rwd +.slideshow_loop.rwd: + ; set BORDER for next image + ld a,(ix) + dec ix + out (254),a + ; call unpack of next image directly into VRAM + ld de,$5AFF ; target VRAM + exx + ; IX = packed data, DE' = destination + ; returned IX will point right ahead of the packed data + call rwd.upkr.unpack + ; do some busy loop with CPU to delay between images + call delay + ; check if all images were displayed, loop around from first one then + ld a,ixl + cp low compressed_scr_files.rwd.e + jr nz,.slideshow_loop.rwd + + jr start + +delay: ld bc,$AA00 .delay: .8 ex (sp),ix dec c jr nz,.delay djnz .delay - ; check if all images were displayed, loop around from first one then - ld a,ixl - cp low compressed_scr_files.e - jr z,start - jr .slideshow_loop + ret ; include the depacker library, optionally putting probs array buffer near end of RAM DEFINE UPKR_PROBS_ORIGIN $FA00 ; if not defined, array will be put after unpack code - INCLUDE "../unpack.asm" + + MODULE fwd + INCLUDE "../unpack.asm" + ENDMODULE + + MODULE rwd + DEFINE BACKWARDS_UNPACK ; defined to build backwards unpack + ; initial IX points at last byte of compressed data + ; initial DE' points at last byte of unpacked data + + INCLUDE "../unpack.asm" + ENDMODULE SAVESNA "example.sna",start diff --git a/z80_unpacker/example/example.sna b/z80_unpacker/example/example.sna index a1f9f56..78df3d8 100644 Binary files a/z80_unpacker/example/example.sna and b/z80_unpacker/example/example.sna differ diff --git a/z80_unpacker/example/screens.reversed/Grongy - ZX Spectrum (2022).scr.upk b/z80_unpacker/example/screens.reversed/Grongy - ZX Spectrum (2022).scr.upk new file mode 100644 index 0000000..0e8777c Binary files /dev/null and b/z80_unpacker/example/screens.reversed/Grongy - ZX Spectrum (2022).scr.upk differ diff --git a/z80_unpacker/example/screens.reversed/Schafft - Poison (2017).scr.upk b/z80_unpacker/example/screens.reversed/Schafft - Poison (2017).scr.upk new file mode 100644 index 0000000..32f5401 Binary files /dev/null and b/z80_unpacker/example/screens.reversed/Schafft - Poison (2017).scr.upk differ diff --git a/z80_unpacker/example/screens.reversed/diver - Back to Bjork (2015).scr.upk b/z80_unpacker/example/screens.reversed/diver - Back to Bjork (2015).scr.upk new file mode 100644 index 0000000..423885a Binary files /dev/null and b/z80_unpacker/example/screens.reversed/diver - Back to Bjork (2015).scr.upk differ diff --git a/z80_unpacker/example/screens.reversed/diver - Mercenary 4. The Heaven's Devil (2014) (Forever 2014 Olympic Edition, 1).scr.upk b/z80_unpacker/example/screens.reversed/diver - Mercenary 4. The Heaven's Devil (2014) (Forever 2014 Olympic Edition, 1).scr.upk new file mode 100644 index 0000000..5e2e2ae Binary files /dev/null and b/z80_unpacker/example/screens.reversed/diver - Mercenary 4. The Heaven's Devil (2014) (Forever 2014 Olympic Edition, 1).scr.upk differ diff --git a/z80_unpacker/unpack.asm b/z80_unpacker/unpack.asm index c788a70..b7e5120 100644 --- a/z80_unpacker/unpack.asm +++ b/z80_unpacker/unpack.asm @@ -15,6 +15,10 @@ ;; modifies: all registers except IY, requires 10 bytes of stack space ;; +; DEFINE BACKWARDS_UNPACK ; uncomment to build backwards depacker + ; initial IX points at last byte of compressed data + ; initial DE' points at last byte of unpacked data + ; DEFINE UPKR_UNPACK_SPEED ; uncomment to get larger but faster unpack routine OPT push reset --syntax=abf @@ -102,7 +106,7 @@ unpack: ld a,c exx ld (de),a ; *write_ptr++ = byte; - inc de + IFNDEF BACKWARDS_UNPACK : inc de : ELSE : dec de : ENDIF exx ld d,b ; prev_was_match = false jr .decompress_data @@ -139,9 +143,13 @@ unpack: ld h,d ; DE = write_ptr ld l,e .offset+*: ld bc,0 + IFNDEF BACKWARDS_UNPACK sbc hl,bc ; CF=0 from decode_number ; HL = write_ptr - offset + ELSE + add hl,bc ; HL = write_ptr + offset + ENDIF pop bc ; BC = length - ldir + IFNDEF BACKWARDS_UNPACK : ldir : ELSE : lddr : ENDIF exx ld d,b ; prev_was_match = true djnz .decompress_data ; adjust context_index back to 0..255 range, go to main loop @@ -195,7 +203,7 @@ decode_bit: jr nz,.has_bit ; CF=data, ZF=0 -> some bits + stop bit still available ; CF=1 (by stop bit) ld a,(ix) - inc ix ; upkr_current_byte = *upkr_data_ptr++; + IFNDEF BACKWARDS_UNPACK : inc ix : ELSE : dec ix : ENDIF ; upkr_current_byte = *upkr_data_ptr++; adc a,a ; CF=data, b0=1 as new stop bit .has_bit: adc hl,hl ; upkr_state = (upkr_state << 1) + (upkr_current_byte >> 7); @@ -306,12 +314,12 @@ decode_number: ; reserve space for probs array without emitting any machine code (using only EQU) IFDEF UPKR_PROBS_ORIGIN ; if specific address is defined by user, move probs array there - ORG UPKR_PROBS_ORIGIN +probs: EQU ((UPKR_PROBS_ORIGIN) + 255) & -$100 ; probs array aligned to 256 + ELSE +probs: EQU ($ + 255) & -$100 ; probs array aligned to 256 ENDIF - -probs: EQU ($+255) & -$100 ; probs array aligned to 256 -.real_c: EQU 1 + 255 + 1 + 2*NUMBER_BITS ; real size of probs array -.c: EQU (.real_c + 1) & -2 ; padding to even size (required by init code) +.real_c: EQU 1 + 255 + 1 + 2*NUMBER_BITS ; real size of probs array +.c: EQU (.real_c + 1) & -2 ; padding to even size (required by init code) .e: EQU probs + .c DISPLAY "upkr.unpack probs array placed at: ",/A,probs,",\tsize: ",/A,probs.c