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Merge optimizations by Pavel Zagrebin 

Manually merge PR #44
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Emmanuel Marty 2020-04-04 13:29:25 +02:00 committed by GitHub
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asm/8088/LZSA1JMP.ASM
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@ -1,4 +1,4 @@
; lzsa1fta.asm time-efficient decompressor implementation for 808x CPUs.
; lzsa2fta.asm time-efficient decompressor implementation for 808x CPUs.
; Turbo Assembler IDEAL mode dialect.
; (Is supposed to also assemble with NASM's IDEAL mode support, but YMMV.)
;
@ -15,6 +15,7 @@
; - Trashes all data and segment registers
;
; Copyright (C) 2019 Jim Leonard, Emmanuel Marty
; Additional speed optimizations by Pavel Zagrebin
;
; This software is provided 'as-is', without any express or implied
; warranty. In no event will the authors be held liable for any damages
@ -107,7 +108,8 @@
; the 'M' bits in the token form the value 15, and an extra byte follows here,
; with three possible types of value.
;
; 0-237: the value is added to the 15 stored in the token. The final value is 3 + 15 + this byte.
; 0-237: the value is added to the 15 stored in the token.
; The final value is 3 + 15 + this byte.
; 239: a second byte follows. The final match length is 256 + the second byte.
; 238: a second and third byte follow, forming a little-endian 16-bit value.
; The final encoded match length is that 16-bit value.
@ -121,6 +123,14 @@
; have the most code, but these are uncommon paths so the
; tiny speed loss in just these paths is not a concern.
;Setting OPTIMIZE_LONG_RLE to 1 speeds up decompressing long runs of the
;same 16-bit word value, but hurts decompression speed of other data
;types slightly. Turn this on if you know your data has very long 16-bit
;word-based runs (reported as RLE2 sequences in the LZSA compressor output
;with an average length of at least 32 bytes), otherwise leave it off.
OPTIMIZE_LONG_RLE EQU 0
SEGMENT CODE para public
ASSUME cs:CODE, ds:CODE
@ -138,43 +148,35 @@ leml2 EQU OFFSET lit_ext_mat_len_2b
leme2 EQU OFFSET lit_ext_mat_ext_2b
;short-circuit special cases for 0 through 6 literal copies:
l6ml1 EQU OFFSET lit_len_mat_len_1b
l6ml1 EQU OFFSET lit_len_mat_len_1b_6
l6me1 EQU OFFSET lit_len_mat_ext_1b
l6ml2 EQU OFFSET lit_len_mat_len_2b
l6ml2 EQU OFFSET lit_len_mat_len_2b_6
l6me2 EQU OFFSET lit_len_mat_ext_2b
l5ml1 EQU OFFSET lit_len_mat_len_1b + 1
l5ml1 EQU OFFSET lit_len_mat_len_1b_45
l5me1 EQU OFFSET lit_len_mat_ext_1b + 1
l5ml2 EQU OFFSET lit_len_mat_len_2b + 1
l5ml2 EQU OFFSET lit_len_mat_len_2b_45
l5me2 EQU OFFSET lit_len_mat_ext_2b + 1
l4ml1 EQU OFFSET lit_len_mat_len_1b + 2
l4ml1 EQU OFFSET lit_len_mat_len_1b_45 + 1
l4me1 EQU OFFSET lit_len_mat_ext_1b + 2
l4ml2 EQU OFFSET lit_len_mat_len_2b + 2
l4ml2 EQU OFFSET lit_len_mat_len_2b_45 + 1
l4me2 EQU OFFSET lit_len_mat_ext_2b + 2
l3ml1 EQU OFFSET lit_len_mat_len_1b + 3
l3ml1 EQU OFFSET lit_len_mat_len_1b_23
l3me1 EQU OFFSET lit_len_mat_ext_1b + 3
l3ml2 EQU OFFSET lit_len_mat_len_2b + 3
l3ml2 EQU OFFSET lit_len_mat_len_2b_23
l3me2 EQU OFFSET lit_len_mat_ext_2b + 3
l2ml1 EQU OFFSET lit_len_mat_len_1b + 4
l2ml1 EQU OFFSET lit_len_mat_len_1b_23 + 1
l2me1 EQU OFFSET lit_len_mat_ext_1b + 4
l2ml2 EQU OFFSET lit_len_mat_len_2b + 4
l2ml2 EQU OFFSET lit_len_mat_len_2b_23 + 1
l2me2 EQU OFFSET lit_len_mat_ext_2b + 4
l1ml1 EQU OFFSET lit_len_mat_len_1b + 5
l1ml1 EQU OFFSET lit_len_mat_len_1b_01
l1me1 EQU OFFSET lit_len_mat_ext_1b + 5
l1ml2 EQU OFFSET lit_len_mat_len_2b + 5
l1ml2 EQU OFFSET lit_len_mat_len_2b_01
l1me2 EQU OFFSET lit_len_mat_ext_2b + 5
l0ml1 EQU OFFSET lit_len_mat_len_1b + 6 ; MMMM handling comes after LLL code
l0me1 EQU OFFSET lit_len_mat_ext_1b + 6 ; MMMM handling comes after LLL code
l0ml2 EQU OFFSET lit_len_mat_len_2b + 6 ; MMMM handling comes after LLL code
l0me2 EQU OFFSET lit_len_mat_ext_2b + 6 ; MMMM handling comes after LLL code
l0ml1 EQU OFFSET lit_len_mat_len_1b_01 + 1 ; MMMM handling comes after LLL code
l0me1 EQU OFFSET lit_len_mat_ext_1b + 6 ; MMMM handling comes after LLL code
l0ml2 EQU OFFSET lit_len_mat_len_2b_01 + 1 ; MMMM handling comes after LLL code
l0me2 EQU OFFSET lit_len_mat_ext_2b + 6 ; MMMM handling comes after LLL code
; === Hand-written (!) jumptable actually begins here.
; Located before the program code results in an extra JMP and 3 wasted bytes,
; but it makes the code easier to follow in this location.
; Relocate the jump table after the ENDP directive to save 3 bytes.
;
; 7 6 5 4 3 2 1 0
; O L L L M M M M
;
; 0 1 2 3 4 5 6 7 8 9 a b c d e f
jtbl DW l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0me1 ;0
DW l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1me1 ;1
@ -215,7 +217,7 @@ MACRO get_word_match_offset
ENDM
MACRO do_match_copy_long
LOCAL do_run, do_run_w
LOCAL even0,even1,even2,do_run,do_run_w
; Copies a long match as optimally as possible.
; requirements: cx=length, bp=negative offset, ds:si=compdata, es:di=output
; trashes: ax, bx
@ -226,45 +228,52 @@ LOCAL do_run, do_run_w
xchg ax,si ;save si
lea si,[bp+di] ;si = output buffer + negative match offset
cmp bp,-2 ;do we have a byte/word run to optimize?
jae do_run ;perform a run if so, otherwise fall through
;You may be tempted to change "jae" to "jge" because DX is a signed number.
;Don't! The total window is 64k, so if you treat this as a signed comparison,
;you will get incorrect results for offsets over 32K.
IF OPTIMIZE_LONG_RLE
jae do_run ;catch offset = -2 or -1
ELSE
ja do_run ;catch offset = -1
ENDIF
;If we're here, we have a long copy and it isn't byte-overlapping (if it
;overlapped, we'd be in @@do_run) So, let's copy faster with REP MOVSW.
;This affects 8088 only slightly, but is a bigger win on 8086 and higher.
shr cx,1
jnc even0
movsb
even0:
rep movsw
adc cl,0
rep movsb
xchg si,ax ;restore si
mov ds,bx ;restore ds
jmp decode_token
do_run:
IF OPTIMIZE_LONG_RLE
je do_run_w ;if applicable, handle word-sized value faster
ENDIF
xchg dx,ax ;save si into dx, as ax is getting trashed
lodsb ;load first byte of run into al
mov ah,al
shr cx,1
jnc even1
stosb
even1:
rep stosw ;perform word run
adc cl,0
rep stosb ;finish word run
mov si,dx ;restore si
mov ds,bx ;restore ds
jmp decode_token
IF OPTIMIZE_LONG_RLE
do_run_w:
xchg dx,ax ;save si into dx, as ax is getting trashed
lodsw ;load first word of run
shr cx,1
rep stosw ;perform word run
adc cl,0 ;despite 2-byte offset, compressor might
rep stosb ;output odd length. better safe than sorry.
jnc even2
stosb ;should be after rep stosw!
even2:
mov si,dx ;restore si
mov ds,bx ;restore ds
jmp decode_token
ENDIF
ENDM
MACRO do_match_copy
@ -277,6 +286,9 @@ MACRO do_match_copy
mov ds,ax ;ds=es
xchg ax,si ;save si
lea si,[bp+di] ;si = output buffer + negative match offset
movsb
movsb
movsb ;Handle MINMATCH (instead of add cx,MINMATCH)
rep movsb
xchg si,ax ;restore si
mov ds,bx ;restore ds
@ -284,34 +296,36 @@ MACRO do_match_copy
ENDM
MACRO do_literal_copy
LOCAL even
; Copies a literal sequence using words.
; Meant for longer lengths; for 128 bytes or less, use REP MOVSB.
; requirements: cx=length, ds:si=compdata, es:di=output
; must leave cx=0 at exit
shr cx,1
jnc even
movsb
even:
rep movsw
adc cl,0
rep movsb
ENDM
MACRO copy_small_match_len
and al,0FH ;isolate length in token (MMMM)
add al,minmatch ;ax=match length
xchg cx,ax ;cx=match length
do_match_copy ;copy match with cx=length, bp=offset
ENDM
MACRO copy_large_match_len
LOCAL val239, val238, EOD
LOCAL val239,val238,EOD
; Handle MMMM=Fh
; Assumptions: ah=0 from get_????_match_offset's xchg
lodsb ;grab extra match length byte
add al,0Fh+minmatch ;add MATCH_RUN_LEN + MIN_MATCH_SIZE
jz val238 ;if zf & cf, 238: get 16-bit match length
; jz val238 ;if zf & cf, 238: get 16-bit match length
jc val239 ;if cf, 239: get extra match length byte
xchg cx,ax ;otherwise, we have our match length
do_match_copy_long ;copy match with cx=length, bp=offset
val239:
jz val238
lodsb ;ah=0; grab single extra length byte
inc ah ;ax=256+length byte
xchg cx,ax
@ -347,16 +361,27 @@ decode_token:
; Path #1: LLL=0-6, MMMM=0-Eh, O=0 (1-byte match offset)
; Handle LLL=0-6 by jumping directly into # of bytes to copy (6 down to 1)
lit_len_mat_len_1b:
movsb
movsb
movsb
movsb
movsb
lit_len_mat_len_1b_01:
movsb
get_byte_match_offset
copy_small_match_len
lit_len_mat_len_1b_23:
movsb
movsw
get_byte_match_offset
copy_small_match_len
lit_len_mat_len_1b_45:
movsb
movsw
movsw
get_byte_match_offset
copy_small_match_len
lit_len_mat_len_1b_6:
movsw
movsw
movsw
get_byte_match_offset
copy_small_match_len
; Path #2: LLL=0-6, MMMM=Fh, O=0 (1-byte match offset)
lit_len_mat_ext_1b:
@ -375,13 +400,14 @@ lit_ext_mat_len_1b:
; on entry: ax=0 + token, bp=ax
lodsb ;grab extra literal length byte
add al,litrunlen ;add 7h literal run length
jz @@val249_3 ;if zf & cf, 249: get 16-bit literal length
; jz @@val249_3 ;if zf & cf, 249: get 16-bit literal length
jc @@val250_3 ;if cf, 250: get extra literal length byte
xchg cx,ax ;otherwise, we have our literal length
do_literal_copy ;this might be better as rep movsw !!! benchmark
get_byte_match_offset
copy_small_match_len
@@val250_3:
jz @@val249_3
lodsb ;ah=0; grab single extra length byte
inc ah ;ax=256+length byte
xchg cx,ax
@ -401,13 +427,14 @@ lit_ext_mat_ext_1b:
; on entry: ax=0 + token, bp=ax
lodsb ;grab extra literal length byte
add al,litrunlen ;add 7h literal run length
jz @@val249_4 ;if zf & cf, 249: get 16-bit literal length
; jz @@val249_4 ;if zf & cf, 249: get 16-bit literal length
jc @@val250_4 ;if cf, 250: get extra literal length byte
xchg cx,ax ;otherwise, we have our literal length
do_literal_copy ;this might be better as rep movsw !!! benchmark
get_byte_match_offset
copy_large_match_len
@@val250_4:
jz @@val249_4
lodsb ;ah=0; grab single extra length byte
inc ah ;ax=256+length byte
xchg cx,ax
@ -424,17 +451,30 @@ lit_ext_mat_ext_1b:
; Path #5: LLL=0-6, MMMM=0-Eh, O=1 (2-byte match offset)
; Handle LLL=0-6 by jumping directly into # of bytes to copy (6 down to 1)
lit_len_mat_len_2b:
movsb
movsb
movsb
lit_len_mat_len_2b_01:
movsb
get_word_match_offset
copy_small_match_len
lit_len_mat_len_2b_23:
movsb
movsw
get_word_match_offset
copy_small_match_len
lit_len_mat_len_2b_45:
movsb
movsw
movsw
get_word_match_offset
copy_small_match_len
lit_len_mat_len_2b_6:
movsw
movsw
movsw
get_word_match_offset
copy_small_match_len
; Path #6: LLL=0-6, MMMM=Fh, O=1 (2-byte match offset)
; Path #6: LLL=0-6, MMMM=Fh, O=1 (2-byte match offset)
lit_len_mat_ext_2b:
movsb
@ -446,19 +486,19 @@ lit_len_mat_ext_2b:
get_word_match_offset
copy_large_match_len
; Path #7: LLL=7, MMMM=0-Eh, O=1 (2-byte match offset)
lit_ext_mat_len_2b:
; on entry: ax=0 + token, bp=ax
lodsb ;grab extra literal length byte
add al,litrunlen ;add 7h literal run length
jz @@val249_7 ;if zf & cf, 249: get 16-bit literal length
; jz @@val249_7 ;if zf & cf, 249: get 16-bit literal length
jc @@val250_7 ;if cf, 250: get extra literal length byte
xchg cx,ax ;otherwise, we have our literal length
do_literal_copy ;this might be better as rep movsw !!! benchmark
get_word_match_offset
copy_small_match_len
@@val250_7:
jz @@val249_7
lodsb ;ah=0; grab single extra length byte
inc ah ;ax=256+length byte
xchg cx,ax
@ -478,13 +518,14 @@ lit_ext_mat_ext_2b:
; on entry: ax=0 + token, bp=ax
lodsb ;grab extra literal length byte
add al,litrunlen ;add 7h literal run length
jz @@val249_8 ;if zf & cf, 249: get 16-bit literal length
; jz @@val249_8 ;if zf & cf, 249: get 16-bit literal length
jc @@val250_8 ;if cf, 250: get extra literal length byte
xchg cx,ax ;otherwise, we have our literal length
do_literal_copy ;this might be better as rep movsw !!! benchmark
get_word_match_offset
copy_large_match_len
@@val250_8:
jz @@val249_8
lodsb ;ah=0; grab single extra length byte
inc ah ;ax=256+length byte
xchg cx,ax
@ -512,6 +553,8 @@ ENDS CODE
END
;Speed optimization history (decompression times in microseconds @ 4.77 MHz):
; defer add MIN_MATCH_SIZE shuttle 97207 alice 57200 robotron 362884 ++*
; jumptable rewrite, no RLE shuttle 97744 alice 46905 robotron 309032 -++
@ -521,3 +564,18 @@ END
; long match copy #1 16-bit shuttle 92490 alice 46905 robotron 308722 +*+
; long match copy #2 extraB shuttle 92464 alice 46905 robotron 308371 +.+
; long match copy #3 0f->ed shuttle 86765 alice 46864 robotron 303895 +++!
; baseline new test harness shuttle 83925 alice 37948 robotron 269002 ***
; Pavel optimizations shuttle 82225 alice 36798 robotron 261226 +++
; OPTIMIZE_LONG_RLE 1 shuttle 82242 alice 36787 robotron 261392 **-
;
;------
;
;Pavel's optimization history:
; shuttle alice robotron time in 1.193 MHz timer clocks
;baseline 19109 D9A6 570F6
;adc cl,0->adc cl,cl 19035 D9A6 56FAB
;rep movsb->shr cx,1;jnc 18FD4 D998 56F14
;cmp bp,-2->inc bp;inc bp 18F07 D999 56EA3
;jz;jc->jc 18D81 D973 56B2F
;add al,3->movsb x3 18B1E D777 56197
;more lit_len_mat tables 18A83 D341 54ACC