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-2 bytes for 6809 LZSA2 depacker, speed unchanged

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Emmanuel Marty 2020-06-19 18:26:25 +02:00 committed by GitHub
parent a6a69ebe17
commit f198431a71
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 4 additions and 5 deletions
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asm/6809/unlzsa2.s
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@ -1,4 +1,4 @@
; unlzsa2.s - 6809 decompression routine for raw LZSA2 - 192 bytes
; unlzsa2.s - 6809 decompression routine for raw LZSA2 - 190 bytes
; compress with lzsa -f2 -r <original_file> <compressed_file>
;
; in: x = start of compressed data
@ -24,8 +24,7 @@
; 3. This notice may not be removed or altered from any source distribution.
decompress_lzsa2
ldb #$00
stb lz2nibct,pcr ; clear nibble available flag
lsr <lz2nibct,pcr ; reset nibble available flag
lz2token ldb ,x+ ; load next token into B: XYZ|LL|MMM
pshs b ; save it
@ -87,7 +86,7 @@ lz2offs9 lda #$00 ; clear A (to prepare for high 8 bits of offset)
ldb ,x+ ; load low 8 bits of (negative, signed) offset
bra lz2gotof
lz2nibct rmb 1 ; nibble ready flag
lz2nibct fcb $00 ; nibble ready flag
lz2nibl ldb #$aa
lsr lz2nibct,pcr ; nibble ready?
@ -125,7 +124,7 @@ lz2rep16 bmi lz2repof ; if token's Z flag bit is set, rep match
ldd ,x++ ; load high then low 8 bits of offset
lz2gotof std lz2repof+1,pcr ; store match offset
lz2gotof std <lz2repof+1,pcr ; store match offset
lz2repof ldd #$aaaa ; load match offset
leau d,y ; put backreference start address in U (dst+offset)