836 lines
18 KiB
NASM
836 lines
18 KiB
NASM
|
;Command set 1 jump table
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CODE_BB8000:
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NOP
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JMP CODE_BB8E2A
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CODE_BB8004:
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NOP
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JMP CODE_BB8E96
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CODE_BB8008:
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NOP
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JMP CODE_BB8EB4
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CODE_BB800C:
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NOP
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JMP CODE_BB8EEB
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CODE_BB8010:
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NOP
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JMP CODE_BB8F26
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CODE_BB8014:
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NOP
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JMP CODE_BB8F53
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CODE_BB8018:
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NOP
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JMP CODE_BB8F80
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CODE_BB801C:
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NOP
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JMP CODE_BB8F9C
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CODE_BB8020:
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NOP
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JMP CODE_BB8FAE
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CODE_BB8024:
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NOP
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JMP CODE_BB8FC0
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CODE_BB8028:
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NOP
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JMP CODE_BB8FFF
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CODE_BB802C:
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NOP
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JMP CODE_BB9062
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CODE_BB8030:
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NOP
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JMP CODE_BB90C9
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CODE_BB8034:
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NOP
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JMP CODE_BB9138
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CODE_BB8038:
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NOP
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JMP CODE_BB9150
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CODE_BB803C:
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NOP
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JMP CODE_BB9176
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;Command set 2 jump table
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CODE_BB8040:
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JMP CODE_BB8E6F
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CODE_BB8043:
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NOP
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JMP CODE_BB8EAA
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CODE_BB8047:
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NOP
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JMP CODE_BB8EDB
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CODE_BB804B:
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NOP
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JMP CODE_BB8F01
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CODE_BB804F:
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NOP
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JMP CODE_BB8F3B
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CODE_BB8053:
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NOP
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JMP CODE_BB8F68
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CODE_BB8057:
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NOP
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JMP CODE_BB8F8E
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CODE_BB805B:
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NOP
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JMP CODE_BB8FA5
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CODE_BB805F:
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NOP
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JMP CODE_BB8FB7
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CODE_BB8063:
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NOP
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JMP CODE_BB8FDE
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CODE_BB8067:
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NOP
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JMP CODE_BB9029
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CODE_BB806B:
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NOP
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JMP CODE_BB9097
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CODE_BB806F:
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NOP
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JMP CODE_BB90F2
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CODE_BB8073:
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NOP
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JMP CODE_BB9144
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CODE_BB8077:
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NOP
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JMP CODE_BB9163
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CODE_BB807B:
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NOP
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JMP CODE_BB9190
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;$38 -- destination
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;$34 -- source
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;$32 -- run dma after upload (always #$FFFF so never)
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;The follow two tables map to the opposite intended nibbles.
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;$42 -- index >> 4 (look up table pointer, set low byte and read for value)
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; This table allow direct indexing of low nibbles
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;$46 -- (index & 0x0F) << 4 (look up table pointer, set low byte and read for value)
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; This table allow direct indexing of high nibbles
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;$4A -- command set starting at $BB8040
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;$4E -- command set starting at $BB8000
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;These are the 6 header bytes of compressed data
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;$52 -- fill byte 1
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;$53 -- fill byte 2
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;$56 -- direct byte 1
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;$57 -- direct byte 2
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;$54 -- direct word
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;Misc addresses
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;$3C -- operand 1 (usually count)
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;$3E -- operand 2 (usually offset)
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;Extra notes
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;All commands are return addresses - 1 so RTS can be used
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CODE_BB8D91: ;
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STA $38 ;\ Set decompression parameters
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LDA #$007F ; |
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STA $3A ; |
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STX $34 ; |
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STY $36 ; |
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BRA CODE_BB8DAE ;/
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;
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CODE_BB8D9E: ;
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TXA ;\ Set decompression parameters
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TYX ; |
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STA $34 ; |
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STX $36 ; |
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LDA #$0000 ; | Default destination $7F0000
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STA $38 ; |
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LDA #$007F ; |
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STA $3A ;/
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CODE_BB8DAE: ;
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LDA #$FFFF ;\ Disble auto DMA of data
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STA $32 ;/
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PHB ;\ Preserve call bank/Y
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PHY ;/
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LDA #$2100 ;\ Setup pointers to nibble look up tables
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STA $46 ; |
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LDA #$007E ; |
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STA $48 ; |
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STA $44 ; |
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LDA #$2000 ; |
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STA $42 ;/
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JSL CODE_BB91AF ; Generate nibble offset table at RAM $7E2000
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LDX $38 ; Load the decompression index
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LDY #$0001 ; Load the compression index
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LDA #$8001 ;\ Load default decompression function A 8001
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STA $4E ;/ The high byte will never change.
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LDA #$8040 ;\ Load default decompression function B 8040
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STA $4A ;/
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SEP #$20 ;
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LDA $3A ;\ Set the data bank to the destination bank
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PHA ; |
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PLB ;/
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LDA [$34],y ;\ Read fill byte 1
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STA $52 ; |
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INY ;/
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LDA [$34],y ;\ Read fill byte 2
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STA $53 ; |
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INY ;/
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LDA [$34],y ;\ Read direct byte 1
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STA $56 ; |
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INY ;/
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LDA [$34],y ;\ Read direct byte 2
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STA $57 ; |
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INY ;/
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REP #$20 ;\ Read direct word
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LDA [$34],y ; |
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STA $54 ;/
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LDY #$0027 ; Skip to compressed byte #$27
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STZ $3C ;\ Clear generic operand 1
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STZ $3E ;/ Clean generic operand 2
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SEP #$20 ; Return to 8 bit
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CODE_BB8E02: ;
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LDA [$34],y ;\ Read the first command byte
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INY ; |
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STA $46 ;/
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AND #$F0 ;\ Command = (byte & 0xF0) >> 2
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LSR A ; | Range $00-$3C
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LSR A ; |
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STA $4E ;/
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PEI ($4E) ;\ Push and execute command
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RTS ;/
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;
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CODE_BB8E10: ;
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LDA $46 ; Read next command byte
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AND #$0F ;\ Command = (byte & 0xF0) >> 2
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ASL A ; | Range $3F-$7B
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ASL A ; |
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ADC #$3F ;/
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STA $4A ;
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PEI ($4A) ;\ Push and execute command
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RTS ;/
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;
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CODE_BB8E1D: ;
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LDA $42 ; Read next command byte
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AND #$0F ;\ Command = (byte & 0xF0) >> 2
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ASL A ; | Range $3F-$7B
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ASL A ; |
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ADC #$3F ; |
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STA $4A ;/
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PEI ($4A) ;\ Push and execute command
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RTS ;/
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;
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CODE_BB8E2A: ;
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LDA $46 ;\ Read number of bytes to copy
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AND #$0F ; |
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BEQ CODE_BB8E40 ;/ If zero bytes, conclude decompression
|
||
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STA $3C ; Store number of bytes to copy
|
||
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CODE_BB8E32: ;
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LDA [$34],y ;\ Direct copy of up to 16 bytes
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||
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INY ; |
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||
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STA $0000,x ; |
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INX ; |
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DEC $3C ; |
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BNE CODE_BB8E32 ;/
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JMP CODE_BB8E02 ; Read new command
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;
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CODE_BB8E40: ;
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REP #$20 ;\ Restore 16 bit A, data bank and Y
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PLY ; |
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PLB ;/
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TXA ;\ Calculate the number of decompressed bytes (stored in X)
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SEC ; | X = X - destination (Where X as an operand is the destination offset)
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||
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SBC $38 ; |
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TAX ;/
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LDA $32 ;\ Check if DMA should run
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BMI CODE_BB8E6E ;/
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LDA $58 ;\ This would be a be a DMA to VRAM
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STA $2116 ; | However $32 is a constant and will always be skipped (0xFFFF)
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LDA $38 ; |
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STA $4302 ; |
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LDA $3A ; |
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STA $4304 ; |
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STX $4305 ; |
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LDA #$1801 ; |
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STA $4300 ; |
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SEP #$20 ; |
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LDA #$01 ; |
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STA $420B ; |
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||
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REP #$20 ;/
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||
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CODE_BB8E6E: ;
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RTL ; Done with decompression
|
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;
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CODE_BB8E6F: ;
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LDA [$34],y ;\ Load next operand
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INY ;/
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STA $42 ;\ Store in nibble lookup tables
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STA $46 ;/
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LDA [$42] ;\ Load number of bytes to write
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BEQ CODE_BB8E40 ; | If zero bytes, conclude decompression
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STA $3C ;/ Store number of bytes to write
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CODE_BB8E7C: ;
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LDA [$46] ;\ operand2 = high byte
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STA $3E ;/
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LDA [$34],y ;\ Load next operand
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INY ;/
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STA $42 ;\ Store in nibble lookup tables
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STA $46 ;/
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LDA $3E ; Load operand2
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ORA [$42] ;\ write operand2 | low nibble
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STA $0000,x ;/
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INX ;\ Continue until no there are no more bytes
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DEC $3C ; |
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BNE CODE_BB8E7C ;/
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JMP CODE_BB8E10 ; Run next command
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;
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CODE_BB8E96: ;
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LDA [$46] ;\ Load operand high nibble
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STA $3E ;/
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LDA [$34],y ;\ Load next operand
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INY ; |
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||
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STA $42 ;/
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LDA $3E ; Load operand high nibble
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ORA [$42] ;\ write high nibble | low nibble
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STA $0000,x ; |
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INX ;/
|
||
|
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JMP CODE_BB8E1D ; Run next command
|
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;
|
||
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CODE_BB8EAA: ;
|
||
|
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LDA [$34],y ;\ Copy one byte from the compression stream
|
||
|
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INY ; |
|
||
|
|
STA $0000,x ; |
|
||
|
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INX ;/
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8EB4: ;
|
||
|
|
LDA [$46] ;\ Load operand high nibble into operand2
|
||
|
|
STA $3E ;/
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
INY ;/
|
||
|
|
STA $42 ;\ Store in nibble lookup tables
|
||
|
|
STA $46 ;/
|
||
|
|
LDA $3E ; Load operand2
|
||
|
|
ORA [$42] ;\ write operand2 | low nibble
|
||
|
|
STA $0000,x ; |
|
||
|
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INX ;/
|
||
|
|
LDA [$46] ;\ Load operand high nibble into operand2
|
||
|
|
STA $3E ;/
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
INY ;/
|
||
|
|
STA $42 ; Store in low nibble lookup table
|
||
|
|
LDA $3E ; Load operand2
|
||
|
|
ORA [$42] ;\ write operand2 | low nibble
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ;/
|
||
|
|
JMP CODE_BB8E1D ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8EDB: ;
|
||
|
|
REP #$20 ;\ Copy one word from the compression stream
|
||
|
|
LDA [$34],y ; |
|
||
|
|
STA $0000,x ; |
|
||
|
|
INY ; |
|
||
|
|
INY ; |
|
||
|
|
INX ; |
|
||
|
|
INX ; |
|
||
|
|
SEP #$20 ;/
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8EEB: ;
|
||
|
|
LDA $46 ;\ Load operand
|
||
|
|
AND #$0F ; | Count = operand & 0x0F + 3
|
||
|
|
ADC #$03 ; |
|
||
|
|
STA $3C ;/
|
||
|
|
LDA [$34],y ;\ Load fill byte
|
||
|
|
INY ;/
|
||
|
|
CODE_BB8EF6: ;
|
||
|
|
STA $0000,x ;\ Store and repeat with fill byte.
|
||
|
|
INX ; |
|
||
|
|
DEC $3C ; |
|
||
|
|
BNE CODE_BB8EF6 ;/
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8F01: ;
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
INY ;/
|
||
|
|
STA $42 ;\ Store in nibble lookup tables
|
||
|
|
STA $46 ;/
|
||
|
|
LDA [$42] ;\ Count = low nibble + 3
|
||
|
|
ADC #$03 ; |
|
||
|
|
STA $3C ;/
|
||
|
|
LDA [$46] ;\ Operand2 = high nibble
|
||
|
|
STA $3E ;/
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
INY ; |
|
||
|
|
STA $42 ;/ Store low nibble look up
|
||
|
|
LDA $3E ;\ Load operand2
|
||
|
|
ORA [$42] ;/ fill byte = operand2 | low nibble
|
||
|
|
CODE_BB8F1B: ;
|
||
|
|
STA $0000,x ;\ Store and repeat with fill byte.
|
||
|
|
INX ; |
|
||
|
|
DEC $3C ; |
|
||
|
|
BNE CODE_BB8F1B ;/
|
||
|
|
JMP CODE_BB8E1D ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8F26: ;
|
||
|
|
LDA $46 ;\ Load operand
|
||
|
|
AND #$0F ; | Count = operand & 0x0F + 3
|
||
|
|
ADC #$03 ; |
|
||
|
|
STA $3C ;/
|
||
|
|
LDA $52 ; Load fill byte 1
|
||
|
|
CODE_BB8F30: ;
|
||
|
|
STA $0000,x ;\ Store and repeat with fill byte.
|
||
|
|
INX ; |
|
||
|
|
DEC $3C ; |
|
||
|
|
BNE CODE_BB8F30 ;/
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8F3B: ;
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
INY ; |
|
||
|
|
STA $42 ;/ Store in low nibble lookup
|
||
|
|
LDA [$42] ;\ Count = low nibble + 3
|
||
|
|
ADC #$03 ; |
|
||
|
|
STA $3C ;/
|
||
|
|
LDA $52 ; Load fill byte 1
|
||
|
|
CODE_BB8F48: ;
|
||
|
|
STA $0000,x ;\ Store and repeat with fill byte.
|
||
|
|
INX ; |
|
||
|
|
DEC $3C ; |
|
||
|
|
BNE CODE_BB8F48 ;/
|
||
|
|
JMP CODE_BB8E1D ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8F53: ;
|
||
|
|
LDA $46 ;\ Load operand
|
||
|
|
AND #$0F ; | Count = (operand & 0x0F) + 3
|
||
|
|
ADC #$03 ; |
|
||
|
|
STA $3C ;/
|
||
|
|
LDA $53 ; Load fill byte 2
|
||
|
|
CODE_BB8F5D: ;
|
||
|
|
STA $0000,x ;\ Store and repeat with fill byte.
|
||
|
|
INX ; |
|
||
|
|
DEC $3C ; |
|
||
|
|
BNE CODE_BB8F5D ;/
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8F68: ;
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
INY ; |
|
||
|
|
STA $42 ;/ Store in low nibble lookup
|
||
|
|
LDA [$42] ;\ Count = low nibble + 3
|
||
|
|
ADC #$03 ; |
|
||
|
|
STA $3C ;/
|
||
|
|
LDA $53 ; Load fill byte 2
|
||
|
|
CODE_BB8F75: ;
|
||
|
|
STA $0000,x ;\ Store and repeat with fill byte.
|
||
|
|
INX ; |
|
||
|
|
DEC $3C ; |
|
||
|
|
BNE CODE_BB8F75 ;/
|
||
|
|
JMP CODE_BB8E1D ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8F80: ;
|
||
|
|
REP #$20 ;\ Store direct word
|
||
|
|
LDA $54 ; |
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ; |
|
||
|
|
INX ; |
|
||
|
|
SEP #$20 ;/
|
||
|
|
JMP CODE_BB8E10 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8F8E: ;
|
||
|
|
REP #$20 ;\ Store direct word
|
||
|
|
LDA $54 ; |
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ; |
|
||
|
|
INX ; |
|
||
|
|
SEP #$20 ;/
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8F9C: ;
|
||
|
|
LDA $56 ;\ Store direct byte 1
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ;/
|
||
|
|
JMP CODE_BB8E10 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8FA5: ;
|
||
|
|
LDA $56 ;\ Store direct byte 1
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ;/
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8FAE: ;
|
||
|
|
LDA $57 ;\ Store direct byte 2
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ;/
|
||
|
|
JMP CODE_BB8E10 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8FB7: ;
|
||
|
|
LDA $57 ;\ Store direct byte 2
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ;/
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8FC0: ;
|
||
|
|
PHY ; Preserve compression index
|
||
|
|
LDA $46 ; Load operand
|
||
|
|
AND #$0F ;\ Offset = (operand & 0x0F) + 2
|
||
|
|
ADC #$02 ; |
|
||
|
|
STA $3E ;/
|
||
|
|
REP #$20 ;\ Prepare to copy (1 word) from a previous point in decompressed data
|
||
|
|
TXA ; | The new offset is stored in Y
|
||
|
|
SEC ; | Y = X - offset
|
||
|
|
SBC $3E ; |
|
||
|
|
TAY ;/
|
||
|
|
LDA $0000,y ;\ Copy from previous data
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ; |
|
||
|
|
INX ;/
|
||
|
|
SEP #$20 ; Return to 8 bit A
|
||
|
|
PLY ; Restore compression index
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8FDE: ;
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
INY ; |
|
||
|
|
STA $42 ;/
|
||
|
|
LDA [$42] ;\ Offset = low nibble + 2
|
||
|
|
ADC #$02 ; |
|
||
|
|
STA $3E ;/
|
||
|
|
PHY ; Preserve compression index
|
||
|
|
REP #$20 ;\ Prepare to copy (1 word) from a previous point in decompressed data
|
||
|
|
TXA ; | The new offset is stored in Y
|
||
|
|
SEC ; | Y = X - offset
|
||
|
|
SBC $3E ; |
|
||
|
|
TAY ;/
|
||
|
|
LDA $0000,y ;\ Copy from previous data
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ; |
|
||
|
|
INX ;/
|
||
|
|
SEP #$20 ; Return to 8 bit A
|
||
|
|
PLY ; Restore compression index
|
||
|
|
JMP CODE_BB8E1D ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB8FFF: ;
|
||
|
|
LDA $46 ; Load next operand
|
||
|
|
AND #$0F ;\ Count = (operand & 0x0F) + 3
|
||
|
|
ADC #$03 ; |
|
||
|
|
STA $3C ;/
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
STA $3E ; |
|
||
|
|
INY ;/
|
||
|
|
PHY ; Preserve compression index
|
||
|
|
REP #$20 ;\ Prepare to copy from a previous point in decompressed data
|
||
|
|
TXA ; | The new offset is stored in Y
|
||
|
|
SEC ; | Y = X - count - offset
|
||
|
|
SBC $3C ; |
|
||
|
|
SEC ; |
|
||
|
|
SBC $3E ; |
|
||
|
|
TAY ;/
|
||
|
|
SEP #$20 ; Back to 8 bit A
|
||
|
|
CODE_BB9019: ;
|
||
|
|
LDA $0000,y ;\ Copy from previous data
|
||
|
|
INY ; |
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ;/
|
||
|
|
DEC $3C ;\ Copy count number of bytes
|
||
|
|
BNE CODE_BB9019 ;/
|
||
|
|
PLY ; Restore compression index
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB9029: ;
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
INY ;/
|
||
|
|
STA $42 ;\ Store in nibble look up tables
|
||
|
|
STA $46 ;/
|
||
|
|
LDA [$42] ;\ Count = low nibble + 3
|
||
|
|
ADC #$03 ; |
|
||
|
|
STA $3C ;/
|
||
|
|
LDA [$46] ;\ Store high nibble in offset
|
||
|
|
STA $3E ;/
|
||
|
|
LDA [$34],y ;\ Load next operand and store in the low nibble lookup
|
||
|
|
INY ; |
|
||
|
|
STA $42 ;/
|
||
|
|
LDA [$42] ;\ offset = low nibble | offset
|
||
|
|
ORA $3E ; |
|
||
|
|
STA $3E ;/
|
||
|
|
PHY ; Preserve compression index
|
||
|
|
REP #$20 ;\ Prepare to copy from a previous point in decompressed data
|
||
|
|
TXA ; | The new offset is stored in Y
|
||
|
|
SEC ; | Y = X - count - offset
|
||
|
|
SBC $3C ; |
|
||
|
|
SEC ; |
|
||
|
|
SBC $3E ; |
|
||
|
|
TAY ;/
|
||
|
|
SEP #$20 ; Back to 8 bit A
|
||
|
|
CODE_BB9052: ;
|
||
|
|
LDA $0000,y ;\ Copy from previous data
|
||
|
|
INY ; |
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ;/
|
||
|
|
DEC $3C ;\ Copy count number of bytes
|
||
|
|
BNE CODE_BB9052 ;/
|
||
|
|
PLY ; Restore compression index
|
||
|
|
JMP CODE_BB8E1D ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB9062: ;
|
||
|
|
LDA $46 ; Load next operand
|
||
|
|
AND #$0F ;\ Count = (operand & 0x0F) + 3
|
||
|
|
ADC #$03 ; |
|
||
|
|
STA $3C ;/
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
INY ; |
|
||
|
|
XBA ;/ Store as high byte for the full operand
|
||
|
|
LDA [$34],y ;\ Load next operand store in high byte look up
|
||
|
|
INY ; |
|
||
|
|
STA $46 ;/
|
||
|
|
REP #$20 ; Switch to 16 bit A
|
||
|
|
LSR A ;\ Offset = (operand >> 4) + 0x0103
|
||
|
|
LSR A ; |
|
||
|
|
LSR A ; |
|
||
|
|
LSR A ; |
|
||
|
|
CLC ; |
|
||
|
|
ADC #$0103 ; |
|
||
|
|
STA $40 ;/
|
||
|
|
PHY ; Preserve compression index
|
||
|
|
TXA ;\ Prepare to copy from a previous point in decompressed data
|
||
|
|
SEC ; | Y = X - offset
|
||
|
|
SBC $40 ; |
|
||
|
|
TAY ;/
|
||
|
|
SEP #$20 ; Back to 8 bit A
|
||
|
|
CODE_BB9087: ;
|
||
|
|
LDA $0000,y ;\ Copy from previous data
|
||
|
|
INY ; |
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ;/
|
||
|
|
DEC $3C ;\ Copy count number of bytes
|
||
|
|
BNE CODE_BB9087 ;/
|
||
|
|
PLY ; Restore compression index
|
||
|
|
JMP CODE_BB8E10 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB9097: ;
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
INY ; |
|
||
|
|
STA $42 ;/ Store in low nibble look up table
|
||
|
|
LDA [$42] ;\ Count = low nibble + 3
|
||
|
|
ADC #$03 ; |
|
||
|
|
STA $3C ;/
|
||
|
|
LDA $42 ;\ Copy the low nibble to the operand high byte
|
||
|
|
AND #$0F ; |
|
||
|
|
XBA ;/
|
||
|
|
LDA [$34],y ;\ Load the operand low byte
|
||
|
|
INY ;/
|
||
|
|
REP #$20 ;\ Offset = operand + 0x0103
|
||
|
|
ADC #$0103 ; |
|
||
|
|
STA $40 ;/
|
||
|
|
PHY ; Preserve compression index
|
||
|
|
TXA ;\ Prepare to copy from a previous point in decompressed data
|
||
|
|
SEC ; | Y = X - offset
|
||
|
|
SBC $40 ; |
|
||
|
|
TAY ;/
|
||
|
|
SEP #$20 ; Back to 8 bit A
|
||
|
|
CODE_BB90B9: ;
|
||
|
|
LDA $0000,y ;\ Copy from previous data
|
||
|
|
INY ; |
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ;/
|
||
|
|
DEC $3C ;\ Copy count number of bytes
|
||
|
|
BNE CODE_BB90B9 ;/
|
||
|
|
PLY ; Restore compression index
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB90C9: ;
|
||
|
|
LDA $46 ; Load next operand
|
||
|
|
AND #$0F ;\ Count = (operand & 0x0F) + 3
|
||
|
|
ADC #$03 ; |
|
||
|
|
STA $3C ;/
|
||
|
|
REP #$20 ;\ Read a big endian word for the offset
|
||
|
|
LDA [$34],y ; |
|
||
|
|
XBA ; |
|
||
|
|
STA $40 ;/
|
||
|
|
INY ;\ Increment the compression index
|
||
|
|
INY ;/
|
||
|
|
PHY ; Preserve compression index
|
||
|
|
TXA ;\ Prepare to copy from a previous point in decompressed data
|
||
|
|
SEC ; | Y = X - offset
|
||
|
|
SBC $40 ; |
|
||
|
|
TAY ;/
|
||
|
|
SEP #$20 ; Back to 8 bit A
|
||
|
|
CODE_BB90E2: ;
|
||
|
|
LDA $0000,y ;\ Copy from previous data
|
||
|
|
INY ; |
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ;/
|
||
|
|
DEC $3C ;\ Copy count number of bytes
|
||
|
|
BNE CODE_BB90E2 ;/
|
||
|
|
PLY ; Restore compression index
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB90F2: ;
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
INY ; |
|
||
|
|
STA $42 ;/ Store in low nibble look up table
|
||
|
|
LDA [$42] ;\ Count = low nibble + 3
|
||
|
|
ADC #$03 ; |
|
||
|
|
STA $3C ;/
|
||
|
|
LDA $42 ;\ Copy as the operand high byte
|
||
|
|
XBA ;/
|
||
|
|
LDA [$34],y ;\ Load the operand low byte
|
||
|
|
INY ;/
|
||
|
|
REP #$20 ; Set A to 16 bit
|
||
|
|
ASL A ;\ Offset = (operand << 4)
|
||
|
|
ASL A ; |
|
||
|
|
ASL A ; |
|
||
|
|
ASL A ; |
|
||
|
|
STA $40 ;/
|
||
|
|
AND #$00FF ; Clear the high byte of the offset
|
||
|
|
SEP #$20 ; Resume 8 bit A
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
INY ;/
|
||
|
|
PHY ; Preserve compression index
|
||
|
|
STA $42 ; Store the operand in the low nibble look up table
|
||
|
|
LDA [$42] ;\ Load low nibble
|
||
|
|
REP #$20 ; |
|
||
|
|
AND #$000F ;/
|
||
|
|
ORA $40 ;\ offset = offset | low nibble
|
||
|
|
STA $40 ;/
|
||
|
|
TXA ;\ Prepare to copy from a previous point in decompressed data
|
||
|
|
SEC ; | Y = X - offset
|
||
|
|
SBC $40 ; |
|
||
|
|
TAY ;/
|
||
|
|
SEP #$20 ; Back to 8 bit A
|
||
|
|
CODE_BB9128: ;
|
||
|
|
LDA $0000,y ;\ Copy from previous data
|
||
|
|
INY ; |
|
||
|
|
STA $0000,x ; |
|
||
|
|
INX ;/
|
||
|
|
DEC $3C ;\ Copy count number of bytes
|
||
|
|
BNE CODE_BB9128 ;/
|
||
|
|
PLY ; Restore compression index
|
||
|
|
JMP CODE_BB8E1D ; Run next command Run next command
|
||
|
|
;
|
||
|
|
CODE_BB9138: ;
|
||
|
|
DEX ;\ Copy previous byte to the decompression stream
|
||
|
|
LDA $0000,x ; |
|
||
|
|
STA $0001,x ; |
|
||
|
|
INX ; |
|
||
|
|
INX ;/
|
||
|
|
JMP CODE_BB8E10 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB9144: ;
|
||
|
|
DEX ;\ Copy previous byte to the decompression stream
|
||
|
|
LDA $0000,x ; |
|
||
|
|
STA $0001,x ; |
|
||
|
|
INX ; |
|
||
|
|
INX ;/
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB9150: ;
|
||
|
|
REP #$20 ;\ Copy the previous word to the decompression stream
|
||
|
|
DEX ; |
|
||
|
|
DEX ; | First go back two bytes
|
||
|
|
LDA $0000,x ; |
|
||
|
|
STA $0002,x ; |
|
||
|
|
SEP #$20 ; |
|
||
|
|
INX ; | Then jump ahead four bytes
|
||
|
|
INX ; |
|
||
|
|
INX ; |
|
||
|
|
INX ;/
|
||
|
|
JMP CODE_BB8E10 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB9163: ;
|
||
|
|
REP #$20 ;\ Copy the previous word to the decompression stream
|
||
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DEX ; |
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DEX ; | First go back two bytes
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LDA $0000,x ; |
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STA $0002,x ; |
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SEP #$20 ; |
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INX ; | Then jump ahead four bytes
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INX ; |
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INX ; |
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INX ;/
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JMP CODE_BB8E02 ; Run next command
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||
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|
;
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||
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CODE_BB9176: ;
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PHY ; Preserve compression index
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||
|
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LDA $46 ; Load next operand
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REP #$20 ; Set A to 16 bit
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AND #$000F ;\ Y = (operand << 1) + 7
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ASL A ; |
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ADC #$0007 ; |
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TAY ;/
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||
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LDA [$34],y ;\ Copy word from compression stream to the decompression stream
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STA $0000,x ;/
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||
|
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SEP #$20 ;\ Return to 8 bit A and increment the decompression index
|
||
|
|
INX ; |
|
||
|
|
INX ;/
|
||
|
|
PLY ; Restore compression index
|
||
|
|
JMP CODE_BB8E02 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB9190: ;
|
||
|
|
LDA [$34],y ;\ Load next operand
|
||
|
|
INY ; |
|
||
|
|
STA $46 ;/ Store to high nibble look up table
|
||
|
|
REP #$20 ; Set A to 16 bit
|
||
|
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AND #$00F0 ;\ Operand = operand >> 3
|
||
|
|
LSR A ; |
|
||
|
|
LSR A ; |
|
||
|
|
LSR A ;/
|
||
|
|
PHY ; Preserve compression index
|
||
|
|
ADC #$0007 ;\ Y = operand + 7
|
||
|
|
TAY ;/
|
||
|
|
LDA [$34],y ;\ Copy word from compression stream to the decompression stream
|
||
|
|
STA $0000,x ;/
|
||
|
|
SEP #$20 ;\ Return to 8 bit A and increment the decompression index
|
||
|
|
INX ; |
|
||
|
|
INX ;/
|
||
|
|
PLY ; Restore compression index
|
||
|
|
JMP CODE_BB8E10 ; Run next command
|
||
|
|
;
|
||
|
|
CODE_BB91AF: ;
|
||
|
|
LDY #$0100 ; Prepare to generate the high nibble table
|
||
|
|
TDC ;\ Zero A and X and set 8 bit A
|
||
|
|
TAX ; |
|
||
|
|
SEP #$20 ;/
|
||
|
|
CODE_BB91B6: ;
|
||
|
|
STA $7E2100,x ;\ Store look up value (index & 0x0F) << 4
|
||
|
|
CLC ; |
|
||
|
|
ADC #$10 ; |
|
||
|
|
AND #$F0 ;/
|
||
|
|
INX ;\ Loop through all 256 values
|
||
|
|
DEY ; |
|
||
|
|
BNE CODE_BB91B6 ;/
|
||
|
|
LDY #$0100 ; Prepare to generate the low nibble table
|
||
|
|
LDX #$0000 ;
|
||
|
|
CODE_BB91C9: ;
|
||
|
|
TXA ;\ Store look up value (index >> 4)
|
||
|
|
LSR A ; |
|
||
|
|
LSR A ; |
|
||
|
|
LSR A ; |
|
||
|
|
LSR A ; |
|
||
|
|
STA $7E2000,x ;/
|
||
|
|
INX ;\ Loop through all 256 values
|
||
|
|
DEY ; |
|
||
|
|
BNE CODE_BB91C9 ;/
|
||
|
|
REP #$20 ; Return to 16 bit A
|
||
|
|
RTL ; Done
|