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Optimize match offset code in 6809 LZSA2 depacker

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This commit is contained in:
Doug Masten 2020-06-27 04:17:05 -05:00
parent 03692fca2c
commit 078edef880
1 changed files with 3 additions and 4 deletions
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7
asm/6809/unlzsa2b.s
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@ -1,4 +1,4 @@
; unlzsa2b.s - 6809 backward decompression routine for raw LZSA2 - 175 bytes
; unlzsa2b.s - 6809 backward decompression routine for raw LZSA2 - 174 bytes
; compress with lzsa -f2 -r -b <original_file> <compressed_file>
;
; in: x = last byte of compressed data
@ -119,10 +119,9 @@ lz2lowof ldb ,-x ; load low 8 bits of offset
lz2gotof nega ; reverse sign of offset in D
negb
sbca #0
std <lz2repof+1,pcr ; store match offset
std <lz2repof+2,pcr ; store match offset
lz2repof ldd #$aaaa ; load match offset
leau d,y ; put backreference start address in U (dst+offset)
lz2repof leau $aaaa,y ; put backreference start address in U (dst+offset)
puls b ; restore token