;--------------------------------------------------------- ; PRO-PACK Unpack Source Code - Super NES, Method 1 ; ; Copyright (c) 1992 Rob Northen Computing ; ; File: RNC_1.S ; ; Date: 9.03.92 ;--------------------------------------------------------- ;--------------------------------------------------------- ; Unpack Routine - Super NES, Method 1 ; ; To unpack a packed file (in any data bank) to an output ; buffer (in any data bank) Note: the packed and unpacked ; files are limited to 65536 bytes in length. ; ; To call (assumes 16-bit accumulator) ; ; PEA pack_file&$FFFF ; push low word of packed file ; PEA ^pack_file ; push high word of packed file ; PEA destn_buf&$FFFF ; push low word of output buffer ; PEA ^destn_buf ; push high word of output buffer ; JSL UNPACK ; unpack file to output buffer ; PLA ; PLA ; PLA ; PLA ; ; On exit, ; ; A, X, Y undefined, M=0, X=0 ;--------------------------------------------------------- ;--------------------------------------------------------- ; Equates ;--------------------------------------------------------- BUFF1 EQU $ ; 16-bit address of $21 byte z-page buffer BUFF2 EQU $ ; 24-bit address of $1A0 byte buffer IN EQU BUFF1 OUT EQU IN+4 WRKBUF EQU OUT+2 COUNTS EQU WRKBUF+3 BLOCKS EQU COUNTS+2 BITBUFL EQU BLOCKS+2 BITBUFH EQU BITBUFL+2 BUFBITS EQU BITBUFH+2 BITLEN EQU BUFBITS+2 HUFCDE EQU BITLEN+2 HUFBSE EQU HUFCDE+2 TEMP1 EQU HUFBSE+2 TEMP2 EQU TEMP1+2 TEMP3 EQU TEMP2+2 TEMP4 EQU TEMP3+2 TMPTAB EQU 0 ; indexed from BUFF2 RAWTAB EQU TMPTAB+$20 ; indexed from BUFF2 POSTAB EQU RAWTAB+$80 ; indexed from BUFF2 SLNTAB EQU POSTAB+$80 ; indexed from BUFF2 ;--------------------------------------------------------- UNPACK REP $39 ; 16-bit AXY, clear D and C LDA 6,S ; read low word of output address STA OUT LDA 8,S ; read high word of packed file STA IN+2 LDA 10,S ; read low word of packed file STA IN LDA 4,S PHB ; save current data bank XBA PHA ; push 2 bytes PLB ; 0 PLB ; make output buffer default data bank LDA #BUFF2&$FFFF STA WRKBUF LDA #^BUFF2 STA WRKBUF+2 LDA #17 ADC IN STA IN LDA [IN] AND #$FF STA BLOCKS INC IN LDA [IN] STA BITBUFL STZ BUFBITS LDA #2 JSR GTBITS UNPACK2 LDY #RAWTAB JSR MAKEHUFF LDY #POSTAB JSR MAKEHUFF LDY #SLNTAB JSR MAKEHUFF LDA #16 JSR GTBITS STA COUNTS JMP UNPACK8 UNPACK3 LDY #POSTAB JSR GTVAL STA TEMP2 LDA OUT CLC SBC TEMP2 STA TEMP3 LDY #SLNTAB JSR GTVAL INC A INC A LSR A TAX LDY #0 LDA TEMP2 BNE UNPACK5 SEP $20 ; 8-bit accumulator LDA (TEMP3),Y XBA LDA (TEMP3),Y REP $20 ; 16-bit accumulator UNPACK4 STA (OUT),Y INY INY DEX BNE UNPACK4 BRA UNPACK6 UNPACK5 LDA (TEMP3),Y STA (OUT),Y INY INY DEX BNE UNPACK5 UNPACK6 BCC UNPACK7 SEP $20 ; 8-bit accumulator LDA (TEMP3),Y STA (OUT),Y INY REP $21 ; 16-bit accumulator, clear carry UNPACK7 TYA ADC OUT STA OUT UNPACK8 LDY #RAWTAB JSR GTVAL TAX BEQ UNPACK14 LDY #0 LSR A BEQ UNPACK10 TAX UNPACK9 LDA [IN],Y STA (OUT),Y INY INY DEX BNE UNPACK9 UNPACK10 BCC UNPACK11 SEP $20 ; 8-bit accumulator LDA [IN],Y STA (OUT),Y REP $21 ; 16-bit accumulator, clear carry INY UNPACK11 TYA ADC IN STA IN TYA ADC OUT STA OUT STZ BITBUFH LDA BUFBITS TAY ASL A TAX LDA [IN] CPY #0 BEQ UNPACK13 UNPACK12 ASL A ROL BITBUFH DEY BNE UNPACK12 UNPACK13 STA TEMP1 LDA >MSKTAB,X AND BITBUFL ORA TEMP1 STA BITBUFL UNPACK14 DEC COUNTS BEQ @1 JMP UNPACK3 @1 DEC BLOCKS BEQ @2 JMP UNPACK2 @2 PLB ; restore old data bank RTL ;----------------------------------------------------------- GTVAL LDX BITBUFL BRA GTVAL3 GTVAL2 INY INY GTVAL3 TXA AND [WRKBUF],Y INY INY CMP [WRKBUF],Y BNE GTVAL2 TYA ADC #(15*4+1) TAY LDA [WRKBUF],Y PHA XBA AND #$FF JSR GTBITS PLA AND #$FF CMP #2 BCC GTVAL4 DEC A ASL A PHA LSR A JSR GTBITS PLX ORA >BITTAB,X GTVAL4 RTS BITTAB DW 1 DW 2 DW 4 DW 8 DW $10 DW $20 DW $40 DW $80 DW $100 DW $200 DW $400 DW $800 DW $1000 DW $2000 DW $4000 DW $8000 ;----------------------------------------------------------- GTBITS TAY ASL A TAX LDA >MSKTAB,X AND BITBUFL PHA LDA BITBUFH LDX BUFBITS BEQ GTBITS3 GTBITS2 LSR A ROR BITBUFL DEY BEQ GTBITS4 DEX BEQ GTBITS3 LSR A ROR BITBUFL DEY BEQ GTBITS4 DEX BNE GTBITS2 GTBITS3 INC IN INC IN LDA [IN] LDX #16 BRA GTBITS2 GTBITS4 DEX STX BUFBITS STA BITBUFH PLA GTBITS5 RTS MSKTAB DW 0 DW 1 DW 3 DW 7 DW $F DW $1F DW $3F DW $7F DW $FF DW $1FF DW $3FF DW $7FF DW $FFF DW $1FFF DW $3FFF DW $7FFF DW $FFFF ;----------------------------------------------------------- MAKEHUFF STY TEMP4 LDA #5 JSR GTBITS BEQ GTBITS5 STA TEMP1 STA TEMP2 LDY #0 MAKEHUFF2 PHY LDA #4 JSR GTBITS PLY STA [WRKBUF],Y INY INY DEC TEMP2 BNE MAKEHUFF2 STZ HUFCDE LDA #$8000 STA HUFBSE LDA #1 STA BITLEN MAKEHUFF3 LDA BITLEN LDX TEMP1 LDY #0 MAKEHUFF4 CMP [WRKBUF],Y BNE MAKEHUFF8 PHX STY TEMP3 ASL A TAX LDA >MSKTAB,X LDY TEMP4 STA [WRKBUF],Y INY INY LDA #16 SEC SBC BITLEN PHA LDA HUFCDE STA TEMP2 LDX BITLEN MAKEHUFF5 ASL TEMP2 ROR A DEX BNE MAKEHUFF5 PLX BEQ MAKEHUFF7 MAKEHUFF6 LSR A DEX BNE MAKEHUFF6 MAKEHUFF7 STA [WRKBUF],Y INY INY STY TEMP4 TYA CLC ADC #(15*4) TAY LDA BITLEN XBA SEP $20 ; 8-bit accumulator LDA TEMP3 LSR A REP $21 ; 16-bit accumulator, clear carry STA [WRKBUF],Y LDA HUFBSE ADC HUFCDE STA HUFCDE LDA BITLEN LDY TEMP3 PLX MAKEHUFF8 INY INY DEX BNE MAKEHUFF4 LSR HUFBSE INC BITLEN CMP #16 BNE MAKEHUFF3 RTS