mirror of
https://github.com/emmanuel-marty/lzsa.git
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fast v1
This commit is contained in:
Peter Ferrie
parent
7371486513
commit
9fc9a49d67
303
asm/6502/decompress_fast_v1.asm
Normal file
303
asm/6502/decompress_fast_v1.asm
Normal file
@ -0,0 +1,303 @@
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; -----------------------------------------------------------------------------
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; Decompress raw LZSA1 block. Create one with lzsa -r <original_file> <compressed_file>
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;
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; in:
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; * LZSA_SRC_LO and LZSA_SRC_HI contain the compressed raw block address
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; * LZSA_DST_LO and LZSA_DST_HI contain the destination buffer address
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;
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; out:
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; * LZSA_DST_LO and LZSA_DST_HI contain the last decompressed byte address, +1
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;
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; -----------------------------------------------------------------------------
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; Backward decompression is also supported, use lzsa -r -b <original_file> <compressed_file>
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; To use it, also define BACKWARD_DECOMPRESS=1 before including this code!
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;
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; in:
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; * LZSA_SRC_LO/LZSA_SRC_HI must contain the address of the last byte of compressed data
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; * LZSA_DST_LO/LZSA_DST_HI must contain the address of the last byte of the destination buffer
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;
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; out:
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; * LZSA_DST_LO/LZSA_DST_HI contain the last decompressed byte address, -1
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;
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; -----------------------------------------------------------------------------
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;
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; Copyright (C) 2019 Emmanuel Marty, Peter Ferrie
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;
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; This software is provided 'as-is', without any express or implied
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; warranty. In no event will the authors be held liable for any damages
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; arising from the use of this software.
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;
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; Permission is granted to anyone to use this software for any purpose,
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; including commercial applications, and to alter it and redistribute it
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; freely, subject to the following restrictions:
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;
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; 1. The origin of this software must not be misrepresented; you must not
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; claim that you wrote the original software. If you use this software
|
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; in a product, an acknowledgment in the product documentation would be
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; appreciated but is not required.
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; 2. Altered source versions must be plainly marked as such, and must not be
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; misrepresented as being the original software.
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; 3. This notice may not be removed or altered from any source distribution.
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; -----------------------------------------------------------------------------
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DECOMPRESS_LZSA1_FAST
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LDY #$00
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DECODE_TOKEN
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JSR GETSRC ; read token byte: O|LLL|MMMM
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PHA ; preserve token on stack
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AND #$70 ; isolate literals count
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BEQ NO_LITERALS ; skip if no literals to copy
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CMP #$70 ; LITERALS_RUN_LEN?
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BNE PREPARE_COPY_LITERALS ; if not, count is directly embedded in token
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JSR GETSRC ; get extra byte of variable literals count
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; the carry is always set by the CMP above
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; GETSRC doesn't change it
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SBC #$F9 ; (LITERALS_RUN_LEN)
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BCC PREPARE_COPY_LITERALS_DIRECT
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BEQ LARGE_VARLEN_LITERALS ; if adding up to zero, go grab 16-bit count
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JSR GETSRC ; get single extended byte of variable literals count
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INY ; add 256 to literals count
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BCS PREPARE_COPY_LITERALS_DIRECT ; (*like JMP PREPARE_COPY_LITERALS_DIRECT but shorter)
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LARGE_VARLEN_LITERALS ; handle 16 bits literals count
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; literals count = directly these 16 bits
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JSR GETLARGESRC ; grab low 8 bits in X, high 8 bits in A
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TAY ; put high 8 bits in Y
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TXA
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JMP PREPARE_COPY_LARGE_LITERALS
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PREPARE_COPY_LITERALS
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TAX
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LDA SHIFT_TABLE-1,X ; shift literals length into place
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; -1 because position 00 is reserved
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TAX
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PREPARE_COPY_LARGE_LITERALS
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BEQ COPY_LITERALS
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INY
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COPY_LITERALS
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JSR GETPUT ; copy one byte of literals
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DEX
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BNE COPY_LITERALS
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DEY
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BNE COPY_LITERALS
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NO_LITERALS
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PLA ; retrieve token from stack
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PHA ; preserve token again
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BMI GET_LONG_OFFSET ; $80: 16 bit offset
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JSR GETSRC ; get 8 bit offset from stream in A
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TAX ; save for later
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LDA #$FF ; high 8 bits
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BNE GOT_OFFSET ; go prepare match
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; (*like JMP GOT_OFFSET but shorter)
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SHORT_VARLEN_MATCHLEN
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JSR GETSRC ; get single extended byte of variable match len
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INY ; add 256 to match length
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PREPARE_COPY_MATCH
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TAX
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PREPARE_COPY_MATCH_Y
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TXA
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BEQ COPY_MATCH_LOOP
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INY
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COPY_MATCH_LOOP
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LDA $AAAA ; get one byte of backreference
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JSR PUTDST ; copy to destination
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!ifdef BACKWARD_DECOMPRESS {
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; Backward decompression -- put backreference bytes backward
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LDA COPY_MATCH_LOOP+1
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BEQ GETMATCH_ADJ_HI
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GETMATCH_DONE
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DEC COPY_MATCH_LOOP+1
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} else {
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; Forward decompression -- put backreference bytes forward
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INC COPY_MATCH_LOOP+1
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BEQ GETMATCH_ADJ_HI
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GETMATCH_DONE
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}
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DEX
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BNE COPY_MATCH_LOOP
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DEY
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BNE COPY_MATCH_LOOP
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BEQ DECODE_TOKEN ; (*like JMP DECODE_TOKEN but shorter)
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!ifdef BACKWARD_DECOMPRESS {
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GETMATCH_ADJ_HI
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DEC COPY_MATCH_LOOP+2
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JMP GETMATCH_DONE
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} else {
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GETMATCH_ADJ_HI
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INC COPY_MATCH_LOOP+2
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JMP GETMATCH_DONE
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}
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GET_LONG_OFFSET ; handle 16 bit offset:
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JSR GETLARGESRC ; grab low 8 bits in X, high 8 bits in A
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GOT_OFFSET
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!ifdef BACKWARD_DECOMPRESS {
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; Backward decompression - substract match offset
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STA OFFSHI ; store high 8 bits of offset
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STX OFFSLO
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SEC ; substract dest - match offset
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LDA PUTDST+1
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OFFSLO = *+1
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SBC #$AA ; low 8 bits
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STA COPY_MATCH_LOOP+1 ; store back reference address
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LDA PUTDST+2
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OFFSHI = *+1
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SBC #$AA ; high 8 bits
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STA COPY_MATCH_LOOP+2 ; store high 8 bits of address
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SEC
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} else {
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; Forward decompression - add match offset
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STA OFFSHI ; store high 8 bits of offset
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TXA
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CLC ; add dest + match offset
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ADC PUTDST+1 ; low 8 bits
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STA COPY_MATCH_LOOP+1 ; store back reference address
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OFFSHI = *+1
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LDA #$AA ; high 8 bits
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ADC PUTDST+2
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STA COPY_MATCH_LOOP+2 ; store high 8 bits of address
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}
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PLA ; retrieve token from stack again
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AND #$0F ; isolate match len (MMMM)
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ADC #$02 ; plus carry which is always set by the high ADC
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CMP #$12 ; MATCH_RUN_LEN?
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BCC PREPARE_COPY_MATCH ; if not, count is directly embedded in token
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JSR GETSRC ; get extra byte of variable match length
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; the carry is always set by the CMP above
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; GETSRC doesn't change it
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SBC #$EE ; add MATCH_RUN_LEN and MIN_MATCH_SIZE to match length
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BCC PREPARE_COPY_MATCH
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BNE SHORT_VARLEN_MATCHLEN
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; Handle 16 bits match length
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JSR GETLARGESRC ; grab low 8 bits in X, high 8 bits in A
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TAY ; put high 8 bits in Y
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; large match length with zero high byte?
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BNE PREPARE_COPY_MATCH_Y ; if not, continue
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DECOMPRESSION_DONE
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RTS
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SHIFT_TABLE
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DB 00h,00h,00h,00h,00h,00h,00h,00h,00h,00h,00h,00h,00h,00h,00h
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DB 01h,01h,01h,01h,01h,01h,01h,01h,01h,01h,01h,01h,01h,01h,01h,01h
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DB 02h,02h,02h,02h,02h,02h,02h,02h,02h,02h,02h,02h,02h,02h,02h,02h
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DB 03h,03h,03h,03h,03h,03h,03h,03h,03h,03h,03h,03h,03h,03h,03h,03h
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DB 04h,04h,04h,04h,04h,04h,04h,04h,04h,04h,04h,04h,04h,04h,04h,04h
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DB 05h,05h,05h,05h,05h,05h,05h,05h,05h,05h,05h,05h,05h,05h,05h,05h
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DB 06h,06h,06h,06h,06h,06h,06h,06h,06h,06h,06h,06h,06h,06h,06h,06h
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DB 07h,07h,07h,07h,07h,07h,07h,07h,07h,07h,07h,07h,07h,07h,07h,07h
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!ifdef BACKWARD_DECOMPRESS {
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; Backward decompression -- get and put bytes backward
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GETPUT
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JSR GETSRC
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PUTDST
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LZSA_DST_LO = *+1
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LZSA_DST_HI = *+2
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STA $AAAA
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LDA PUTDST+1
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BEQ PUTDST_ADJ_HI
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PUTDST_DONE
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DEC PUTDST+1
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RTS
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PUTDST_ADJ_HI
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DEC PUTDST+2
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JMP PUTDST_DONE
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GETLARGESRC
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JSR GETSRC ; grab low 8 bits
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TAX ; move to X
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; fall through grab high 8 bits
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GETSRC
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LZSA_SRC_LO = *+1
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LZSA_SRC_HI = *+2
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LDA $AAAA
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PHA
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LDA GETSRC+1
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BEQ GETSRC_ADJ_HI
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GETSRC_DONE
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DEC GETSRC+1
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PLA
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RTS
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GETSRC_ADJ_HI
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DEC GETSRC+2
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JMP GETSRC_DONE
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} else {
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; Forward decompression -- get and put bytes forward
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GETPUT
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JSR GETSRC
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PUTDST
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LZSA_DST_LO = *+1
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LZSA_DST_HI = *+2
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STA $AAAA
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INC PUTDST+1
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BEQ PUTDST_ADJ_HI
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RTS
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PUTDST_ADJ_HI
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INC PUTDST+2
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RTS
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GETLARGESRC
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JSR GETSRC ; grab low 8 bits
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TAX ; move to X
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; fall through grab high 8 bits
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GETSRC
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LZSA_SRC_LO = *+1
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LZSA_SRC_HI = *+2
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LDA $AAAA
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INC GETSRC+1
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BEQ GETSRC_ADJ_HI
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RTS
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GETSRC_ADJ_HI
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INC GETSRC+2
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RTS
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}
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540
asm/6502/decompress_v1.asm → asm/6502/decompress_small_v1.asm
Executable file → Normal file
540
asm/6502/decompress_v1.asm → asm/6502/decompress_small_v1.asm
Executable file → Normal file
@ -1,270 +1,270 @@
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; -----------------------------------------------------------------------------
|
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; Decompress raw LZSA1 block. Create one with lzsa -r <original_file> <compressed_file>
|
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;
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; in:
|
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; * LZSA_SRC_LO and LZSA_SRC_HI contain the compressed raw block address
|
||||
; * LZSA_DST_LO and LZSA_DST_HI contain the destination buffer address
|
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;
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; out:
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; * LZSA_DST_LO and LZSA_DST_HI contain the last decompressed byte address, +1
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;
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; -----------------------------------------------------------------------------
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; Backward decompression is also supported, use lzsa -r -b <original_file> <compressed_file>
|
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; To use it, also define BACKWARD_DECOMPRESS=1 before including this code!
|
||||
;
|
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; in:
|
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; * LZSA_SRC_LO/LZSA_SRC_HI must contain the address of the last byte of compressed data
|
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; * LZSA_DST_LO/LZSA_DST_HI must contain the address of the last byte of the destination buffer
|
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;
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; out:
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; * LZSA_DST_LO/LZSA_DST_HI contain the last decompressed byte address, -1
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;
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; -----------------------------------------------------------------------------
|
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;
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; Copyright (C) 2019 Emmanuel Marty
|
||||
;
|
||||
; This software is provided 'as-is', without any express or implied
|
||||
; warranty. In no event will the authors be held liable for any damages
|
||||
; arising from the use of this software.
|
||||
;
|
||||
; Permission is granted to anyone to use this software for any purpose,
|
||||
; including commercial applications, and to alter it and redistribute it
|
||||
; freely, subject to the following restrictions:
|
||||
;
|
||||
; 1. The origin of this software must not be misrepresented; you must not
|
||||
; claim that you wrote the original software. If you use this software
|
||||
; in a product, an acknowledgment in the product documentation would be
|
||||
; appreciated but is not required.
|
||||
; 2. Altered source versions must be plainly marked as such, and must not be
|
||||
; misrepresented as being the original software.
|
||||
; 3. This notice may not be removed or altered from any source distribution.
|
||||
; -----------------------------------------------------------------------------
|
||||
|
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DECOMPRESS_LZSA1
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LDY #$00
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DECODE_TOKEN
|
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JSR GETSRC ; read token byte: O|LLL|MMMM
|
||||
PHA ; preserve token on stack
|
||||
|
||||
AND #$70 ; isolate literals count
|
||||
BEQ NO_LITERALS ; skip if no literals to copy
|
||||
LSR ; shift literals count into place
|
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LSR
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LSR
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LSR
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CMP #$07 ; LITERALS_RUN_LEN?
|
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BCC PREPARE_COPY_LITERALS ; if not, count is directly embedded in token
|
||||
|
||||
JSR GETSRC ; get extra byte of variable literals count
|
||||
; the carry is always set by the CMP above
|
||||
; GETSRC doesn't change it
|
||||
SBC #$F9 ; (LITERALS_RUN_LEN)
|
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BCC PREPARE_COPY_LITERALS
|
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BEQ LARGE_VARLEN_LITERALS ; if adding up to zero, go grab 16-bit count
|
||||
|
||||
JSR GETSRC ; get single extended byte of variable literals count
|
||||
INY ; add 256 to literals count
|
||||
BCS PREPARE_COPY_LITERALS ; (*like JMP PREPARE_COPY_LITERALS but shorter)
|
||||
|
||||
LARGE_VARLEN_LITERALS ; handle 16 bits literals count
|
||||
; literals count = directly these 16 bits
|
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JSR GETLARGESRC ; grab low 8 bits in X, high 8 bits in A
|
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TAY ; put high 8 bits in Y
|
||||
TXA
|
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|
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PREPARE_COPY_LITERALS
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TAX
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BEQ COPY_LITERALS
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INY
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|
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COPY_LITERALS
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JSR GETPUT ; copy one byte of literals
|
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DEX
|
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BNE COPY_LITERALS
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DEY
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BNE COPY_LITERALS
|
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|
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NO_LITERALS
|
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PLA ; retrieve token from stack
|
||||
PHA ; preserve token again
|
||||
BMI GET_LONG_OFFSET ; $80: 16 bit offset
|
||||
|
||||
JSR GETSRC ; get 8 bit offset from stream in A
|
||||
TAX ; save for later
|
||||
LDA #$FF ; high 8 bits
|
||||
BNE GOT_OFFSET ; go prepare match
|
||||
; (*like JMP GOT_OFFSET but shorter)
|
||||
|
||||
SHORT_VARLEN_MATCHLEN
|
||||
JSR GETSRC ; get single extended byte of variable match len
|
||||
INY ; add 256 to match length
|
||||
|
||||
PREPARE_COPY_MATCH
|
||||
TAX
|
||||
PREPARE_COPY_MATCH_Y
|
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TXA
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||||
BEQ COPY_MATCH_LOOP
|
||||
INY
|
||||
|
||||
COPY_MATCH_LOOP
|
||||
LDA $AAAA ; get one byte of backreference
|
||||
JSR PUTDST ; copy to destination
|
||||
|
||||
!ifdef BACKWARD_DECOMPRESS {
|
||||
|
||||
; Backward decompression -- put backreference bytes backward
|
||||
|
||||
LDA COPY_MATCH_LOOP+1
|
||||
BNE GETMATCH_DONE
|
||||
DEC COPY_MATCH_LOOP+2
|
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GETMATCH_DONE
|
||||
DEC COPY_MATCH_LOOP+1
|
||||
|
||||
} else {
|
||||
|
||||
; Forward decompression -- put backreference bytes forward
|
||||
|
||||
INC COPY_MATCH_LOOP+1
|
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BNE GETMATCH_DONE
|
||||
INC COPY_MATCH_LOOP+2
|
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GETMATCH_DONE
|
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|
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}
|
||||
|
||||
DEX
|
||||
BNE COPY_MATCH_LOOP
|
||||
DEY
|
||||
BNE COPY_MATCH_LOOP
|
||||
BEQ DECODE_TOKEN ; (*like JMP DECODE_TOKEN but shorter)
|
||||
|
||||
GET_LONG_OFFSET ; handle 16 bit offset:
|
||||
JSR GETLARGESRC ; grab low 8 bits in X, high 8 bits in A
|
||||
|
||||
GOT_OFFSET
|
||||
|
||||
!ifdef BACKWARD_DECOMPRESS {
|
||||
|
||||
; Backward decompression - substract match offset
|
||||
|
||||
STA OFFSHI ; store high 8 bits of offset
|
||||
STX OFFSLO
|
||||
|
||||
SEC ; substract dest - match offset
|
||||
LDA PUTDST+1
|
||||
OFFSLO = *+1
|
||||
SBC #$AA ; low 8 bits
|
||||
STA COPY_MATCH_LOOP+1 ; store back reference address
|
||||
LDA PUTDST+2
|
||||
OFFSHI = *+1
|
||||
SBC #$AA ; high 8 bits
|
||||
STA COPY_MATCH_LOOP+2 ; store high 8 bits of address
|
||||
SEC
|
||||
|
||||
} else {
|
||||
|
||||
; Forward decompression - add match offset
|
||||
|
||||
STA OFFSHI ; store high 8 bits of offset
|
||||
TXA
|
||||
|
||||
CLC ; add dest + match offset
|
||||
ADC PUTDST+1 ; low 8 bits
|
||||
STA COPY_MATCH_LOOP+1 ; store back reference address
|
||||
OFFSHI = *+1
|
||||
LDA #$AA ; high 8 bits
|
||||
|
||||
ADC PUTDST+2
|
||||
STA COPY_MATCH_LOOP+2 ; store high 8 bits of address
|
||||
|
||||
}
|
||||
|
||||
PLA ; retrieve token from stack again
|
||||
AND #$0F ; isolate match len (MMMM)
|
||||
ADC #$02 ; plus carry which is always set by the high ADC
|
||||
CMP #$12 ; MATCH_RUN_LEN?
|
||||
BCC PREPARE_COPY_MATCH ; if not, count is directly embedded in token
|
||||
|
||||
JSR GETSRC ; get extra byte of variable match length
|
||||
; the carry is always set by the CMP above
|
||||
; GETSRC doesn't change it
|
||||
SBC #$EE ; add MATCH_RUN_LEN and MIN_MATCH_SIZE to match length
|
||||
BCC PREPARE_COPY_MATCH
|
||||
BNE SHORT_VARLEN_MATCHLEN
|
||||
|
||||
; Handle 16 bits match length
|
||||
JSR GETLARGESRC ; grab low 8 bits in X, high 8 bits in A
|
||||
TAY ; put high 8 bits in Y
|
||||
; large match length with zero high byte?
|
||||
BNE PREPARE_COPY_MATCH_Y ; if not, continue
|
||||
|
||||
DECOMPRESSION_DONE
|
||||
RTS
|
||||
|
||||
!ifdef BACKWARD_DECOMPRESS {
|
||||
|
||||
; Backward decompression -- get and put bytes backward
|
||||
|
||||
GETPUT
|
||||
JSR GETSRC
|
||||
PUTDST
|
||||
LZSA_DST_LO = *+1
|
||||
LZSA_DST_HI = *+2
|
||||
STA $AAAA
|
||||
LDA PUTDST+1
|
||||
BNE PUTDST_DONE
|
||||
DEC PUTDST+2
|
||||
PUTDST_DONE
|
||||
DEC PUTDST+1
|
||||
RTS
|
||||
|
||||
GETLARGESRC
|
||||
JSR GETSRC ; grab low 8 bits
|
||||
TAX ; move to X
|
||||
; fall through grab high 8 bits
|
||||
|
||||
GETSRC
|
||||
LZSA_SRC_LO = *+1
|
||||
LZSA_SRC_HI = *+2
|
||||
LDA $AAAA
|
||||
PHA
|
||||
LDA GETSRC+1
|
||||
BNE GETSRC_DONE
|
||||
DEC GETSRC+2
|
||||
GETSRC_DONE
|
||||
DEC GETSRC+1
|
||||
PLA
|
||||
RTS
|
||||
|
||||
} else {
|
||||
|
||||
; Forward decompression -- get and put bytes forward
|
||||
|
||||
GETPUT
|
||||
JSR GETSRC
|
||||
PUTDST
|
||||
LZSA_DST_LO = *+1
|
||||
LZSA_DST_HI = *+2
|
||||
STA $AAAA
|
||||
INC PUTDST+1
|
||||
BNE PUTDST_DONE
|
||||
INC PUTDST+2
|
||||
PUTDST_DONE
|
||||
RTS
|
||||
|
||||
GETLARGESRC
|
||||
JSR GETSRC ; grab low 8 bits
|
||||
TAX ; move to X
|
||||
; fall through grab high 8 bits
|
||||
|
||||
GETSRC
|
||||
LZSA_SRC_LO = *+1
|
||||
LZSA_SRC_HI = *+2
|
||||
LDA $AAAA
|
||||
INC GETSRC+1
|
||||
BNE GETSRC_DONE
|
||||
INC GETSRC+2
|
||||
GETSRC_DONE
|
||||
RTS
|
||||
|
||||
}
|
||||
; -----------------------------------------------------------------------------
|
||||
; Decompress raw LZSA1 block. Create one with lzsa -r <original_file> <compressed_file>
|
||||
;
|
||||
; in:
|
||||
; * LZSA_SRC_LO and LZSA_SRC_HI contain the compressed raw block address
|
||||
; * LZSA_DST_LO and LZSA_DST_HI contain the destination buffer address
|
||||
;
|
||||
; out:
|
||||
; * LZSA_DST_LO and LZSA_DST_HI contain the last decompressed byte address, +1
|
||||
;
|
||||
; -----------------------------------------------------------------------------
|
||||
; Backward decompression is also supported, use lzsa -r -b <original_file> <compressed_file>
|
||||
; To use it, also define BACKWARD_DECOMPRESS=1 before including this code!
|
||||
;
|
||||
; in:
|
||||
; * LZSA_SRC_LO/LZSA_SRC_HI must contain the address of the last byte of compressed data
|
||||
; * LZSA_DST_LO/LZSA_DST_HI must contain the address of the last byte of the destination buffer
|
||||
;
|
||||
; out:
|
||||
; * LZSA_DST_LO/LZSA_DST_HI contain the last decompressed byte address, -1
|
||||
;
|
||||
; -----------------------------------------------------------------------------
|
||||
;
|
||||
; Copyright (C) 2019 Emmanuel Marty
|
||||
;
|
||||
; This software is provided 'as-is', without any express or implied
|
||||
; warranty. In no event will the authors be held liable for any damages
|
||||
; arising from the use of this software.
|
||||
;
|
||||
; Permission is granted to anyone to use this software for any purpose,
|
||||
; including commercial applications, and to alter it and redistribute it
|
||||
; freely, subject to the following restrictions:
|
||||
;
|
||||
; 1. The origin of this software must not be misrepresented; you must not
|
||||
; claim that you wrote the original software. If you use this software
|
||||
; in a product, an acknowledgment in the product documentation would be
|
||||
; appreciated but is not required.
|
||||
; 2. Altered source versions must be plainly marked as such, and must not be
|
||||
; misrepresented as being the original software.
|
||||
; 3. This notice may not be removed or altered from any source distribution.
|
||||
; -----------------------------------------------------------------------------
|
||||
|
||||
DECOMPRESS_LZSA1
|
||||
LDY #$00
|
||||
|
||||
DECODE_TOKEN
|
||||
JSR GETSRC ; read token byte: O|LLL|MMMM
|
||||
PHA ; preserve token on stack
|
||||
|
||||
AND #$70 ; isolate literals count
|
||||
BEQ NO_LITERALS ; skip if no literals to copy
|
||||
LSR ; shift literals count into place
|
||||
LSR
|
||||
LSR
|
||||
LSR
|
||||
CMP #$07 ; LITERALS_RUN_LEN?
|
||||
BCC PREPARE_COPY_LITERALS ; if not, count is directly embedded in token
|
||||
|
||||
JSR GETSRC ; get extra byte of variable literals count
|
||||
; the carry is always set by the CMP above
|
||||
; GETSRC doesn't change it
|
||||
SBC #$F9 ; (LITERALS_RUN_LEN)
|
||||
BCC PREPARE_COPY_LITERALS
|
||||
BEQ LARGE_VARLEN_LITERALS ; if adding up to zero, go grab 16-bit count
|
||||
|
||||
JSR GETSRC ; get single extended byte of variable literals count
|
||||
INY ; add 256 to literals count
|
||||
BCS PREPARE_COPY_LITERALS ; (*like JMP PREPARE_COPY_LITERALS but shorter)
|
||||
|
||||
LARGE_VARLEN_LITERALS ; handle 16 bits literals count
|
||||
; literals count = directly these 16 bits
|
||||
JSR GETLARGESRC ; grab low 8 bits in X, high 8 bits in A
|
||||
TAY ; put high 8 bits in Y
|
||||
TXA
|
||||
|
||||
PREPARE_COPY_LITERALS
|
||||
TAX
|
||||
BEQ COPY_LITERALS
|
||||
INY
|
||||
|
||||
COPY_LITERALS
|
||||
JSR GETPUT ; copy one byte of literals
|
||||
DEX
|
||||
BNE COPY_LITERALS
|
||||
DEY
|
||||
BNE COPY_LITERALS
|
||||
|
||||
NO_LITERALS
|
||||
PLA ; retrieve token from stack
|
||||
PHA ; preserve token again
|
||||
BMI GET_LONG_OFFSET ; $80: 16 bit offset
|
||||
|
||||
JSR GETSRC ; get 8 bit offset from stream in A
|
||||
TAX ; save for later
|
||||
LDA #$FF ; high 8 bits
|
||||
BNE GOT_OFFSET ; go prepare match
|
||||
; (*like JMP GOT_OFFSET but shorter)
|
||||
|
||||
SHORT_VARLEN_MATCHLEN
|
||||
JSR GETSRC ; get single extended byte of variable match len
|
||||
INY ; add 256 to match length
|
||||
|
||||
PREPARE_COPY_MATCH
|
||||
TAX
|
||||
PREPARE_COPY_MATCH_Y
|
||||
TXA
|
||||
BEQ COPY_MATCH_LOOP
|
||||
INY
|
||||
|
||||
COPY_MATCH_LOOP
|
||||
LDA $AAAA ; get one byte of backreference
|
||||
JSR PUTDST ; copy to destination
|
||||
|
||||
!ifdef BACKWARD_DECOMPRESS {
|
||||
|
||||
; Backward decompression -- put backreference bytes backward
|
||||
|
||||
LDA COPY_MATCH_LOOP+1
|
||||
BNE GETMATCH_DONE
|
||||
DEC COPY_MATCH_LOOP+2
|
||||
GETMATCH_DONE
|
||||
DEC COPY_MATCH_LOOP+1
|
||||
|
||||
} else {
|
||||
|
||||
; Forward decompression -- put backreference bytes forward
|
||||
|
||||
INC COPY_MATCH_LOOP+1
|
||||
BNE GETMATCH_DONE
|
||||
INC COPY_MATCH_LOOP+2
|
||||
GETMATCH_DONE
|
||||
|
||||
}
|
||||
|
||||
DEX
|
||||
BNE COPY_MATCH_LOOP
|
||||
DEY
|
||||
BNE COPY_MATCH_LOOP
|
||||
BEQ DECODE_TOKEN ; (*like JMP DECODE_TOKEN but shorter)
|
||||
|
||||
GET_LONG_OFFSET ; handle 16 bit offset:
|
||||
JSR GETLARGESRC ; grab low 8 bits in X, high 8 bits in A
|
||||
|
||||
GOT_OFFSET
|
||||
|
||||
!ifdef BACKWARD_DECOMPRESS {
|
||||
|
||||
; Backward decompression - substract match offset
|
||||
|
||||
STA OFFSHI ; store high 8 bits of offset
|
||||
STX OFFSLO
|
||||
|
||||
SEC ; substract dest - match offset
|
||||
LDA PUTDST+1
|
||||
OFFSLO = *+1
|
||||
SBC #$AA ; low 8 bits
|
||||
STA COPY_MATCH_LOOP+1 ; store back reference address
|
||||
LDA PUTDST+2
|
||||
OFFSHI = *+1
|
||||
SBC #$AA ; high 8 bits
|
||||
STA COPY_MATCH_LOOP+2 ; store high 8 bits of address
|
||||
SEC
|
||||
|
||||
} else {
|
||||
|
||||
; Forward decompression - add match offset
|
||||
|
||||
STA OFFSHI ; store high 8 bits of offset
|
||||
TXA
|
||||
|
||||
CLC ; add dest + match offset
|
||||
ADC PUTDST+1 ; low 8 bits
|
||||
STA COPY_MATCH_LOOP+1 ; store back reference address
|
||||
OFFSHI = *+1
|
||||
LDA #$AA ; high 8 bits
|
||||
|
||||
ADC PUTDST+2
|
||||
STA COPY_MATCH_LOOP+2 ; store high 8 bits of address
|
||||
|
||||
}
|
||||
|
||||
PLA ; retrieve token from stack again
|
||||
AND #$0F ; isolate match len (MMMM)
|
||||
ADC #$02 ; plus carry which is always set by the high ADC
|
||||
CMP #$12 ; MATCH_RUN_LEN?
|
||||
BCC PREPARE_COPY_MATCH ; if not, count is directly embedded in token
|
||||
|
||||
JSR GETSRC ; get extra byte of variable match length
|
||||
; the carry is always set by the CMP above
|
||||
; GETSRC doesn't change it
|
||||
SBC #$EE ; add MATCH_RUN_LEN and MIN_MATCH_SIZE to match length
|
||||
BCC PREPARE_COPY_MATCH
|
||||
BNE SHORT_VARLEN_MATCHLEN
|
||||
|
||||
; Handle 16 bits match length
|
||||
JSR GETLARGESRC ; grab low 8 bits in X, high 8 bits in A
|
||||
TAY ; put high 8 bits in Y
|
||||
; large match length with zero high byte?
|
||||
BNE PREPARE_COPY_MATCH_Y ; if not, continue
|
||||
|
||||
DECOMPRESSION_DONE
|
||||
RTS
|
||||
|
||||
!ifdef BACKWARD_DECOMPRESS {
|
||||
|
||||
; Backward decompression -- get and put bytes backward
|
||||
|
||||
GETPUT
|
||||
JSR GETSRC
|
||||
PUTDST
|
||||
LZSA_DST_LO = *+1
|
||||
LZSA_DST_HI = *+2
|
||||
STA $AAAA
|
||||
LDA PUTDST+1
|
||||
BNE PUTDST_DONE
|
||||
DEC PUTDST+2
|
||||
PUTDST_DONE
|
||||
DEC PUTDST+1
|
||||
RTS
|
||||
|
||||
GETLARGESRC
|
||||
JSR GETSRC ; grab low 8 bits
|
||||
TAX ; move to X
|
||||
; fall through grab high 8 bits
|
||||
|
||||
GETSRC
|
||||
LZSA_SRC_LO = *+1
|
||||
LZSA_SRC_HI = *+2
|
||||
LDA $AAAA
|
||||
PHA
|
||||
LDA GETSRC+1
|
||||
BNE GETSRC_DONE
|
||||
DEC GETSRC+2
|
||||
GETSRC_DONE
|
||||
DEC GETSRC+1
|
||||
PLA
|
||||
RTS
|
||||
|
||||
} else {
|
||||
|
||||
; Forward decompression -- get and put bytes forward
|
||||
|
||||
GETPUT
|
||||
JSR GETSRC
|
||||
PUTDST
|
||||
LZSA_DST_LO = *+1
|
||||
LZSA_DST_HI = *+2
|
||||
STA $AAAA
|
||||
INC PUTDST+1
|
||||
BNE PUTDST_DONE
|
||||
INC PUTDST+2
|
||||
PUTDST_DONE
|
||||
RTS
|
||||
|
||||
GETLARGESRC
|
||||
JSR GETSRC ; grab low 8 bits
|
||||
TAX ; move to X
|
||||
; fall through grab high 8 bits
|
||||
|
||||
GETSRC
|
||||
LZSA_SRC_LO = *+1
|
||||
LZSA_SRC_HI = *+2
|
||||
LDA $AAAA
|
||||
INC GETSRC+1
|
||||
BNE GETSRC_DONE
|
||||
INC GETSRC+2
|
||||
GETSRC_DONE
|
||||
RTS
|
||||
|
||||
}
|
||||
Loading…
x
Reference in New Issue
Block a user