chiptune_player: prepare for playing whole song
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Vince Weaver
parent
daf51b5474
commit
6f13857beb
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@ -30,36 +30,34 @@
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; 4 added to it. As with the literal length, if it is 15 then
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; you read a byte and add (and if that byte is 255, keep adding)
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src EQU $FC
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dst EQU $02
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end EQU $04
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count EQU $06
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delta EQU $08
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;LZ4_SRC EQU $00
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;LZ4_DST EQU $02
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;LZ4_END EQU $04
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;COUNT EQU $06
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;DELTA EQU $08
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orgoff EQU $6000 ; offset of first unpacked byte
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;======================
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; LZ4 decode
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;======================
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; input buffer in INH:INL
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; input buffer in LZ4_SRC
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; output buffer hardcoded still
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; size in ENDH:ENDL
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lz4_decode:
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lda INL ; packed data offset
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; sta src
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lda LZ4_SRC ; packed data offset
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clc
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adc end
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sta end
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lda INH
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; sta src+1
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adc end+1
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sta end+1
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adc LZ4_END
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sta LZ4_END
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lda LZ4_SRC+1
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adc LZ4_END+1
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sta LZ4_END+1
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lda #>orgoff ; original unpacked data offset
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sta dst+1
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sta LZ4_DST+1
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lda #<orgoff
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sta dst
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sta LZ4_DST
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unpmain:
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ldy #0 ; used to index, always zero
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@ -80,17 +78,17 @@ parsetoken:
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tax ; now in ram[count+1]-1:X
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jsr docopy ; copy the literals
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lda src ; 16-bit compare
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cmp end ; to see if we have reached the end
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lda src+1
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sbc end+1
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lda LZ4_SRC ; 16-bit compare
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cmp LZ4_END ; to see if we have reached the end
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lda LZ4_SRC+1
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sbc LZ4_END+1
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bcs done
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copymatches:
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jsr getsrc ; get 16-bit delta value
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sta delta
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sta DELTA
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jsr getsrc
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sta delta+1
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sta DELTA+1
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pla ; restore token
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and #$0f ; get bottom 4 bits
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@ -108,28 +106,28 @@ copymatches:
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; exactly a multiple of 0x100
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bcc copy_no_adjust
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inc count+1 ; increment if we overflowed
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inc COUNT+1 ; increment if we overflowed
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copy_no_adjust:
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lda src+1 ; save src on stack
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lda LZ4_SRC+1 ; save src on stack
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pha
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lda src
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lda LZ4_SRC
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pha
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sec ; subtract delta
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lda dst ; from destination, make new src
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sbc delta
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sta src
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lda dst+1
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sbc delta+1
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sta src+1
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lda LZ4_DST ; from destination, make new src
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sbc DELTA
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sta LZ4_SRC
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lda LZ4_DST+1
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sbc DELTA+1
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sta LZ4_SRC+1
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jsr docopy ; do the copy
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pla ; restore the src
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sta src
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sta LZ4_SRC
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pla
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sta src+1
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sta LZ4_SRC+1
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jmp parsetoken ; back to parsing tokens
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@ -142,10 +140,10 @@ done:
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;=========
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; gets byte from src into A, increments pointer
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getsrc:
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lda (src), Y ; get a byte from src
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inc src ; increment pointer
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lda (LZ4_SRC), Y ; get a byte from src
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inc LZ4_SRC ; increment pointer
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bne done_getsrc ; update 16-bit pointer
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inc src+1 ; on 8-bit overflow
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inc LZ4_SRC+1 ; on 8-bit overflow
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done_getsrc:
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rts
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@ -154,17 +152,17 @@ done_getsrc:
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;============
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buildcount:
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ldx #1 ; high count starts at 1
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stx count+1 ; (loops at zero?)
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stx COUNT+1 ; (loops at zero?)
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cmp #$0f ; if LITERAL_COUNT < 15, we are done
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bne done_buildcount
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buildcount_loop:
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sta count ; save LITERAL_COUNT (15)
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sta COUNT ; save LITERAL_COUNT (15)
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jsr getsrc ; get the next byte
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tax ; put in X
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clc
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adc count ; add new byte to old value
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adc COUNT ; add new byte to old value
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bcc bc_8bit_oflow ; if overflow, increment high byte
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inc count+1
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inc COUNT+1
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bc_8bit_oflow:
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inx ; check if read value was 255
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beq buildcount_loop ; if it was, keep looping and adding
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@ -184,10 +182,10 @@ getput:
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;=============
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; store A into destination
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putdst:
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sta (dst), Y ; store A into destination
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inc dst ; increment 16-bit pointer
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sta (LZ4_DST), Y ; store A into destination
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inc LZ4_DST ; increment 16-bit pointer
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bne putdst_end ; if overflow, increment top byte
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inc dst+1
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inc LZ4_DST+1
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putdst_end:
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rts
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@ -202,7 +200,7 @@ docopy_loop:
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jsr getput ; get/put byte
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dex ; decrement count
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bne docopy_loop ; if not zero, loop
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dec count+1 ; if zero, decrement high byte
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dec COUNT+1 ; if zero, decrement high byte
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bne docopy_loop ; if not zero, loop
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rts
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@ -433,37 +433,33 @@ bloop2:
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bloop3:
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jsr print_both_pages
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SIZEL EQU $04
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SIZEH EQU $05
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ldy #0
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lda #>(LZ4_BUFFER+3)
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sta INH
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sta LZ4_SRC+1
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lda #<(LZ4_BUFFER+3)
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sta INL
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sta LZ4_SRC
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lda (INL),Y ; get header skip
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lda (LZ4_SRC),Y ; get header skip
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clc
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adc INL
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sta INL
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lda INH
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adc LZ4_SRC
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sta LZ4_SRC
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lda LZ4_SRC+1
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adc #0
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sta INH
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sta LZ4_SRC+1
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lda (INL),Y
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sta SIZEL
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lda (LZ4_SRC),Y
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sta LZ4_END
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iny
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lda (INL),Y
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sta SIZEH
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lda (LZ4_SRC),Y
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sta LZ4_END+1
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lda #2
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clc
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adc INL
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sta INL
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lda INH
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adc LZ4_SRC
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sta LZ4_SRC
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lda LZ4_SRC+1
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adc #0
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sta INH
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sta LZ4_SRC+1
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jsr lz4_decode
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@ -1,5 +1,12 @@
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.define EQU =
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LZ4_SRC EQU $00
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LZ4_DST EQU $02
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LZ4_END EQU $04
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COUNT EQU $06
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DELTA EQU $08
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;; Zero page monitor routines addresses
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WNDLFT EQU $20
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