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Make 6809 depacker for LZSA1 smaller/faster

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Emmanuel Marty 2020-06-18 17:46:42 +02:00 committed by GitHub
parent 3ce9a2b36e
commit 1d0427ecae
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1 changed files with 5 additions and 5 deletions
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10
asm/6809/unlzsa1.s
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@ -1,4 +1,4 @@
; unlzsa1.s - 6809 decompression routine for raw LZSA1 - 125 bytes ; unlzsa1.s - 6809 decompression routine for raw LZSA1 - 121 bytes
; compress with lzsa -r <original_file> <compressed_file> ; compress with lzsa -r <original_file> <compressed_file>
; ;
; in: x = start of compressed data ; in: x = start of compressed data
@ -40,11 +40,11 @@ lz1token ldb ,x+ ; load next token into B: O|LLL|MMMM
ldb ,x+ ; load low 8 bits of little-endian literals count ldb ,x+ ; load low 8 bits of little-endian literals count
lda ,x+ ; load high 8 bits of literal count lda ,x+ ; load high 8 bits of literal count
jmp lz1gotlt ; we now have the complete count, go copy bra lz1gotlt ; we now have the complete count, go copy
lz1midlt tfr b,a ; copy high part of literals count into A lz1midlt tfr b,a ; copy high part of literals count into A
ldb ,x+ ; load low 8 bits of literals count ldb ,x+ ; load low 8 bits of literals count
jmp lz1gotlt ; we now have the complete count, go copy bra lz1gotlt ; we now have the complete count, go copy
lz1declt lsrb ; shift literals count into place lz1declt lsrb ; shift literals count into place
lsrb lsrb
@ -67,7 +67,7 @@ lz1nolt puls b ; restore token
ldb ,x+ ; O clear: load 8 bit (negative, signed) offset ldb ,x+ ; O clear: load 8 bit (negative, signed) offset
lda #$ff ; set high 8 bits lda #$ff ; set high 8 bits
jmp lz1gotof bra lz1gotof
lz1bigof ldb ,x+ ; O set: load long 16 bit (negative, signed) offset lz1bigof ldb ,x+ ; O set: load long 16 bit (negative, signed) offset
lda ,x+ ; (little endian) lda ,x+ ; (little endian)
@ -106,4 +106,4 @@ lz1cpymt lda ,u+ ; copy matched byte
bne lz1cpymt ; loop until all matched bytes are copied bne lz1cpymt ; loop until all matched bytes are copied
puls x ; restore source compressed data pointer puls x ; restore source compressed data pointer
jmp lz1token ; go decode next token bra lz1token ; go decode next token