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Merge pull request #9 from MobyGamer/decompressor/8086_speed

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Additional 1% speedup from deferring work
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Emmanuel Marty 2019-07-09 20:42:17 +02:00 committed by GitHub
commit 467cd1970f
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1 changed files with 7 additions and 4 deletions
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11
asm/8088/LZSA1FTA.ASM
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@ -67,14 +67,13 @@ lzsa1_start:
mov dx,ax ;keep token in dl
and al,070H ;isolate literals length in token (LLL)
segcs xlat ;shift literals length into place
cmp al,07H ;LITERALS_RUN_LEN?
jz @@check_offset_size ;if LLL=0, we have no literals; goto match
cmp al,070H ;LITERALS_RUN_LEN?
jne @@got_literals ;no, we have full count from token; go copy
lodsb ;grab extra length byte
add al,07H ;add LITERALS_RUN_LEN
jnc @@got_literals ;if no overflow, we have full count; go copy
jnc @@got_literals_exact ;if no overflow, we have full count
jne @@mid_literals
@@big_literals:
@ -97,6 +96,8 @@ lzsa1_start:
jmp @@check_offset_size
@@got_literals:
segcs xlat ;shift literals length into place
@@got_literals_exact:
xchg cx,ax
rep movsb ;copy cx literals from ds:si to es:di
@@check_offset_size:
@ -233,3 +234,5 @@ END
; reverse 16-bit len compar shuttle 102000 alice 59263 robotron 364460 --- rb
; jcxz for EOD detection no change to speed, but is 1 byte shorter +++
; force movsw for literals shuttle 107183 alice 62555 robotron 379524 --- rb
; defer shr4 until necessry shuttle 102069 alice 60236 robotron 364096 --- rb
; skip literals if LLL=0 shuttle 98655 alice 57849 robotron 363358 --- rb