Игры использующие
Nemesis compressionAlien Storm
Bare Knuckle 2
Castle of Illusion
Columns
Dr. Robotnik's Mean Bean Machine
ESWAT
Fatal Labyrinth
Flicky
Forgotten Worlds
Ghostbusters
Ghouls 'n' Ghosts
Golden Axe
Golden Axe 2
Golden Axe 3
Knuckles' Chaotix (32X)
Mercs
Moonwalker
Phantasy Star II (SegaNet text adventures)
PulseMan
Quackshot
Revenge of Shinobi
Ristar
Sega Mega Anser
Shadow Dancer
Sonic & Knuckles
Sonic Compilation
Sonic Crackers
Sonic Eraser
Sonic Jam (Saturn)
Sonic the Hedgehog
Sonic the Hedgehog 2
Sonic the Hedgehog 3
Sonic the Hedgehog CD (Mega CD)
Streets of Rage
Streets of Rage 3
Strider
Super Hang-On
Super Monaco GP
World Cup Italia '90
World of Illusion
Добавлено позже:кто знает что в других играх отпишитесь пизззз
Добавлено позже:Декомпрессор
Nemesis; ---------------------------------------------------------------------------
; Nemesis decompression subroutine, decompresses art directly to VRAM
; Inputs:
; a0 = art address
; a VDP command to write to the destination VRAM address must be issued
; before calling this routine
; ---------------------------------------------------------------------------
; =============== S U B R O U T I N E =======================================
Nem_Decomp:
movem.l d0-a1/a3-a5,-(sp)
lea (Nem_PCD_WriteRowToVDP).l,a3
lea (VDP_data_port).l,a4 ; write all rows to the VDP data port
bra.s Nem_Decomp_Main
; End of function Nem_Decomp
; ---------------------------------------------------------------------------
; Nemesis decompression subroutine, decompresses art to RAM
; Inputs:
; a0 = art address
; a4 = destination RAM address
; ---------------------------------------------------------------------------
; =============== S U B R O U T I N E =======================================
Nem_Decomp_To_RAM:
movem.l d0-a1/a3-a5,-(sp)
lea (Nem_PCD_WriteRowToRAM).l,a3
; End of function Nem_Decomp_To_RAM
; ---------------------------------------------------------------------------
; Main Nemesis decompression subroutine
; ---------------------------------------------------------------------------
; =============== S U B R O U T I N E =======================================
Nem_Decomp_Main:
lea (Nem_code_table).w,a1
move.w (a0)+,d2 ; get number of patterns
lsl.w #1,d2
bcc.s + ; branch if the sign bit isn't set
adda.w #Nem_PCD_WriteRowToVDP_XOR-Nem_PCD_WriteRowToVDP,a3 ; otherwise the file uses XOR mode
+
lsl.w #2,d2 ; get number of 8-pixel rows in the uncompressed data
movea.w d2,a5 ; and store it in a5 because there aren't any spare data registers
moveq #8,d3 ; 8 pixels in a pattern row
moveq #0,d2
moveq #0,d4
bsr.w Nem_Build_Code_Table
move.b (a0)+,d5 ; get first byte of compressed data
asl.w #8,d5 ; shift up by a byte
move.b (a0)+,d5 ; get second byte of compressed data
move.w #$10,d6 ; set initial shift value
bsr.s Nem_Process_Compressed_Data
movem.l (sp)+,d0-a1/a3-a5
rts
; End of function Nem_Decomp_Main
; ---------------------------------------------------------------------------
; Part of the Nemesis decompressor, processes the actual compressed data
; ---------------------------------------------------------------------------
; =============== S U B R O U T I N E =======================================
; PCD is used throughout this subroutine as an initialism for Process_Compressed_Data
Nem_Process_Compressed_Data:
move.w d6,d7
subq.w #8,d7 ; get shift value
move.w d5,d1
lsr.w d7,d1 ; shift so that high bit of the code is in bit position 7
cmpi.b #%11111100,d1 ; are the high 6 bits set?
bcc.s Nem_PCD_InlineData ; if they are, it signifies inline data
andi.w #$FF,d1
add.w d1,d1
move.b (a1,d1.w),d0 ; get the length of the code in bits
ext.w d0
sub.w d0,d6 ; subtract from shift value so that the next code is read next time around
cmpi.w #9,d6 ; does a new byte need to be read?
bcc.s + ; if not, branch
addq.w #8,d6
asl.w #8,d5
move.b (a0)+,d5 ; read next byte
+
move.b 1(a1,d1.w),d1
move.w d1,d0
andi.w #$F,d1 ; get palette index for pixel
andi.w #$F0,d0
Nem_PCD_GetRepeatCount:
lsr.w #4,d0 ; get repeat count
Nem_PCD_WritePixel:
lsl.l #4,d4 ; shift up by a nybble
or.b d1,d4 ; write pixel
subq.w #1,d3 ; has an entire 8-pixel row been written?
bne.s Nem_PCD_WritePixel_Loop ; if not, loop
jmp (a3) ; otherwise, write the row to its destination
; ---------------------------------------------------------------------------
Nem_PCD_NewRow:
moveq #0,d4 ; reset row
moveq #8,d3 ; reset nybble counter
Nem_PCD_WritePixel_Loop:
dbf d0,Nem_PCD_WritePixel
bra.s Nem_Process_Compressed_Data
; ---------------------------------------------------------------------------
Nem_PCD_InlineData:
subq.w #6,d6 ; 6 bits needed to signal inline data
cmpi.w #9,d6
bcc.s +
addq.w #8,d6
asl.w #8,d5
move.b (a0)+,d5
+
subq.w #7,d6 ; and 7 bits needed for the inline data itself
move.w d5,d1
lsr.w d6,d1 ; shift so that low bit of the code is in bit position 0
move.w d1,d0
andi.w #$F,d1 ; get palette index for pixel
andi.w #$70,d0 ; high nybble is repeat count for pixel
cmpi.w #9,d6
bcc.s Nem_PCD_GetRepeatCount
addq.w #8,d6
asl.w #8,d5
move.b (a0)+,d5
bra.s Nem_PCD_GetRepeatCount
; ---------------------------------------------------------------------------
Nem_PCD_WriteRowToVDP:
move.l d4,(a4) ; write 8-pixel row
subq.w #1,a5
move.w a5,d4 ; have all the 8-pixel rows been written?
bne.s Nem_PCD_NewRow ; if not, branch
rts ; otherwise the decompression is finished
; ---------------------------------------------------------------------------
Nem_PCD_WriteRowToVDP_XOR:
eor.l d4,d2 ; XOR the previous row by the current row
move.l d2,(a4) ; and write the result
subq.w #1,a5
move.w a5,d4
bne.s Nem_PCD_NewRow
rts
; ---------------------------------------------------------------------------
Nem_PCD_WriteRowToRAM:
move.l d4,(a4)+
subq.w #1,a5
move.w a5,d4
bne.s Nem_PCD_NewRow
rts
; ---------------------------------------------------------------------------
Nem_PCD_WriteRowToRAM_XOR:
eor.l d4,d2
move.l d2,(a4)+
subq.w #1,a5
move.w a5,d4
bne.s Nem_PCD_NewRow
rts
; End of function Nem_Process_Compressed_Data
; ---------------------------------------------------------------------------
; Part of the Nemesis decompressor, builds the code table (in RAM)
; ---------------------------------------------------------------------------
; =============== S U B R O U T I N E =======================================
; BCT is used throughout this subroutine as an initialism for Build_Code_Table
Nem_Build_Code_Table:
move.b (a0)+,d0 ; read first byte
Nem_BCT_ChkEnd:
cmpi.b #$FF,d0 ; has the end of the code table description been reached?
bne.s Nem_BCT_NewPalIndex ; if not, branch
rts ; otherwise, this subroutine's work is done
; ---------------------------------------------------------------------------
Nem_BCT_NewPalIndex:
move.w d0,d7
Nem_BCT_Loop:
move.b (a0)+,d0 ; read next byte
cmpi.b #$80,d0 ; sign bit being set signifies a new palette index
bcc.s Nem_BCT_ChkEnd ; a bmi could have been used instead of a compare and bcc
move.b d0,d1
andi.w #$F,d7 ; get palette index
andi.w #$70,d1 ; get repeat count for palette index
or.w d1,d7 ; combine the two
andi.w #$F,d0 ; get the length of the code in bits
move.b d0,d1
lsl.w #8,d1
or.w d1,d7 ; combine with palette index and repeat count to form code table entry
moveq #8,d1
sub.w d0,d1 ; is the code 8 bits long?
bne.s Nem_BCT_ShortCode ; if not, a bit of extra processing is needed
move.b (a0)+,d0 ; get code
add.w d0,d0 ; each code gets a word-sized entry in the table
move.w d7,(a1,d0.w) ; store the entry for the code
bra.s Nem_BCT_Loop ; repeat
; ---------------------------------------------------------------------------
; the Nemesis decompressor uses prefix-free codes (no valid code is a prefix of a longer code)
; e.g. if 10 is a valid 2-bit code, 110 is a valid 3-bit code but 100 isn't
; also, when the actual compressed data is processed the high bit of each code is in bit position 7
; so the code needs to be bit-shifted appropriately over here before being used as a code table index
; additionally, the code needs multiple entries in the table because no masking is done during compressed data processing
; so if 11000 is a valid code then all indices of the form 11000XXX need to have the same entry
Nem_BCT_ShortCode:
move.b (a0)+,d0 ; get code
lsl.w d1,d0 ; shift so that high bit is in bit position 7
add.w d0,d0 ; get index into code table
moveq #1,d5
lsl.w d1,d5
subq.w #1,d5 ; d5 = 2^d1 - 1
Nem_BCT_ShortCode_Loop:
move.w d7,(a1,d0.w) ; store entry
addq.w #2,d0 ; increment index
dbf d5,Nem_BCT_ShortCode_Loop ; repeat for required number of entries
bra.s Nem_BCT_Loop
; End of function Nem_Build_Code_Table
