906 lines
24 KiB
NASM
906 lines
24 KiB
NASM
;
|
||
; gvmat32.asm -- Asm portion of the optimized longest_match for 32 bits x86
|
||
; Copyright (C) 1995-1996 Jean-loup Gailly and Gilles Vollant.
|
||
; File written by Gilles Vollant, by modifiying the longest_match
|
||
; from Jean-loup Gailly in deflate.c
|
||
; It need wmask == 0x7fff
|
||
; (assembly code is faster with a fixed wmask)
|
||
;
|
||
; For Visual C++ 4.2 and ML 6.11c (version in directory \MASM611C of Win95 DDK)
|
||
; I compile with : "ml /coff /Zi /c gvmat32.asm"
|
||
;
|
||
|
||
;uInt longest_match_7fff(s, cur_match)
|
||
; deflate_state *s;
|
||
; IPos cur_match; /* current match */
|
||
|
||
NbStack equ 76
|
||
cur_match equ dword ptr[esp+NbStack-0]
|
||
str_s equ dword ptr[esp+NbStack-4]
|
||
; 5 dword on top (ret,ebp,esi,edi,ebx)
|
||
adrret equ dword ptr[esp+NbStack-8]
|
||
pushebp equ dword ptr[esp+NbStack-12]
|
||
pushedi equ dword ptr[esp+NbStack-16]
|
||
pushesi equ dword ptr[esp+NbStack-20]
|
||
pushebx equ dword ptr[esp+NbStack-24]
|
||
|
||
chain_length equ dword ptr [esp+NbStack-28]
|
||
limit equ dword ptr [esp+NbStack-32]
|
||
best_len equ dword ptr [esp+NbStack-36]
|
||
window equ dword ptr [esp+NbStack-40]
|
||
prev equ dword ptr [esp+NbStack-44]
|
||
scan_start equ word ptr [esp+NbStack-48]
|
||
wmask equ dword ptr [esp+NbStack-52]
|
||
match_start_ptr equ dword ptr [esp+NbStack-56]
|
||
nice_match equ dword ptr [esp+NbStack-60]
|
||
scan equ dword ptr [esp+NbStack-64]
|
||
|
||
windowlen equ dword ptr [esp+NbStack-68]
|
||
match_start equ dword ptr [esp+NbStack-72]
|
||
strend equ dword ptr [esp+NbStack-76]
|
||
NbStackAdd equ (NbStack-24)
|
||
|
||
.386p
|
||
|
||
name gvmatch
|
||
.MODEL FLAT
|
||
|
||
|
||
|
||
; all the +4 offsets are due to the addition of pending_buf_size (in zlib
|
||
; in the deflate_state structure since the asm code was first written
|
||
; (if you compile with zlib 1.0.4 or older, remove the +4).
|
||
; Note : these value are good with a 8 bytes boundary pack structure
|
||
dep_chain_length equ 70h+4
|
||
dep_window equ 2ch+4
|
||
dep_strstart equ 60h+4
|
||
dep_prev_length equ 6ch+4
|
||
dep_nice_match equ 84h+4
|
||
dep_w_size equ 20h+4
|
||
dep_prev equ 34h+4
|
||
dep_w_mask equ 28h+4
|
||
dep_good_match equ 80h+4
|
||
dep_match_start equ 64h+4
|
||
dep_lookahead equ 68h+4
|
||
|
||
|
||
_TEXT segment
|
||
|
||
IFDEF NOUNDERLINE
|
||
public longest_match_7fff
|
||
public longest_match_686
|
||
; public match_init
|
||
ELSE
|
||
public _longest_match_7fff
|
||
public _longest_match_686
|
||
; public _match_init
|
||
ENDIF
|
||
|
||
MAX_MATCH equ 258
|
||
MIN_MATCH equ 3
|
||
MIN_LOOKAHEAD equ (MAX_MATCH+MIN_MATCH+1)
|
||
|
||
|
||
|
||
IFDEF NOUNDERLINE
|
||
;match_init proc near
|
||
; ret
|
||
;match_init endp
|
||
ELSE
|
||
;_match_init proc near
|
||
; ret
|
||
;_match_init endp
|
||
ENDIF
|
||
|
||
|
||
IFDEF NOUNDERLINE
|
||
longest_match_7fff proc near
|
||
ELSE
|
||
_longest_match_7fff proc near
|
||
ENDIF
|
||
|
||
mov edx,[esp+4]
|
||
|
||
|
||
|
||
push ebp
|
||
push edi
|
||
push esi
|
||
push ebx
|
||
|
||
sub esp,NbStackAdd
|
||
|
||
; initialize or check the variables used in match.asm.
|
||
mov ebp,edx
|
||
|
||
; chain_length = s->max_chain_length
|
||
; if (prev_length>=good_match) chain_length >>= 2
|
||
mov edx,[ebp+dep_chain_length]
|
||
mov ebx,[ebp+dep_prev_length]
|
||
cmp [ebp+dep_good_match],ebx
|
||
ja noshr
|
||
shr edx,2
|
||
noshr:
|
||
; we increment chain_length because in the asm, the --chain_lenght is in the beginning of the loop
|
||
inc edx
|
||
mov edi,[ebp+dep_nice_match]
|
||
mov chain_length,edx
|
||
mov eax,[ebp+dep_lookahead]
|
||
cmp eax,edi
|
||
; if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
|
||
jae nolookaheadnicematch
|
||
mov edi,eax
|
||
nolookaheadnicematch:
|
||
; best_len = s->prev_length
|
||
mov best_len,ebx
|
||
|
||
; window = s->window
|
||
mov esi,[ebp+dep_window]
|
||
mov ecx,[ebp+dep_strstart]
|
||
mov window,esi
|
||
|
||
mov nice_match,edi
|
||
; scan = window + strstart
|
||
add esi,ecx
|
||
mov scan,esi
|
||
; dx = *window
|
||
mov dx,word ptr [esi]
|
||
; bx = *(window+best_len-1)
|
||
mov bx,word ptr [esi+ebx-1]
|
||
add esi,MAX_MATCH-1
|
||
; scan_start = *scan
|
||
mov scan_start,dx
|
||
; strend = scan + MAX_MATCH-1
|
||
mov strend,esi
|
||
; bx = scan_end = *(window+best_len-1)
|
||
|
||
; IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
|
||
; s->strstart - (IPos)MAX_DIST(s) : NIL;
|
||
|
||
mov esi,[ebp+dep_w_size]
|
||
sub esi,MIN_LOOKAHEAD
|
||
; here esi = MAX_DIST(s)
|
||
sub ecx,esi
|
||
ja nodist
|
||
xor ecx,ecx
|
||
nodist:
|
||
mov limit,ecx
|
||
|
||
; prev = s->prev
|
||
mov edx,[ebp+dep_prev]
|
||
mov prev,edx
|
||
|
||
;
|
||
mov edx,dword ptr [ebp+dep_match_start]
|
||
mov bp,scan_start
|
||
mov eax,cur_match
|
||
mov match_start,edx
|
||
|
||
mov edx,window
|
||
mov edi,edx
|
||
add edi,best_len
|
||
mov esi,prev
|
||
dec edi
|
||
; windowlen = window + best_len -1
|
||
mov windowlen,edi
|
||
|
||
jmp beginloop2
|
||
align 4
|
||
|
||
; here, in the loop
|
||
; eax = ax = cur_match
|
||
; ecx = limit
|
||
; bx = scan_end
|
||
; bp = scan_start
|
||
; edi = windowlen (window + best_len -1)
|
||
; esi = prev
|
||
|
||
|
||
;// here; chain_length <=16
|
||
normalbeg0add16:
|
||
add chain_length,16
|
||
jz exitloop
|
||
normalbeg0:
|
||
cmp word ptr[edi+eax],bx
|
||
je normalbeg2noroll
|
||
rcontlabnoroll:
|
||
; cur_match = prev[cur_match & wmask]
|
||
and eax,7fffh
|
||
mov ax,word ptr[esi+eax*2]
|
||
; if cur_match > limit, go to exitloop
|
||
cmp ecx,eax
|
||
jnb exitloop
|
||
; if --chain_length != 0, go to exitloop
|
||
dec chain_length
|
||
jnz normalbeg0
|
||
jmp exitloop
|
||
|
||
normalbeg2noroll:
|
||
; if (scan_start==*(cur_match+window)) goto normalbeg2
|
||
cmp bp,word ptr[edx+eax]
|
||
jne rcontlabnoroll
|
||
jmp normalbeg2
|
||
|
||
contloop3:
|
||
mov edi,windowlen
|
||
|
||
; cur_match = prev[cur_match & wmask]
|
||
and eax,7fffh
|
||
mov ax,word ptr[esi+eax*2]
|
||
; if cur_match > limit, go to exitloop
|
||
cmp ecx,eax
|
||
jnbexitloopshort1:
|
||
jnb exitloop
|
||
; if --chain_length != 0, go to exitloop
|
||
|
||
|
||
; begin the main loop
|
||
beginloop2:
|
||
sub chain_length,16+1
|
||
; if chain_length <=16, don't use the unrolled loop
|
||
jna normalbeg0add16
|
||
|
||
do16:
|
||
cmp word ptr[edi+eax],bx
|
||
je normalbeg2dc0
|
||
|
||
maccn MACRO lab
|
||
and eax,7fffh
|
||
mov ax,word ptr[esi+eax*2]
|
||
cmp ecx,eax
|
||
jnb exitloop
|
||
cmp word ptr[edi+eax],bx
|
||
je lab
|
||
ENDM
|
||
|
||
rcontloop0:
|
||
maccn normalbeg2dc1
|
||
|
||
rcontloop1:
|
||
maccn normalbeg2dc2
|
||
|
||
rcontloop2:
|
||
maccn normalbeg2dc3
|
||
|
||
rcontloop3:
|
||
maccn normalbeg2dc4
|
||
|
||
rcontloop4:
|
||
maccn normalbeg2dc5
|
||
|
||
rcontloop5:
|
||
maccn normalbeg2dc6
|
||
|
||
rcontloop6:
|
||
maccn normalbeg2dc7
|
||
|
||
rcontloop7:
|
||
maccn normalbeg2dc8
|
||
|
||
rcontloop8:
|
||
maccn normalbeg2dc9
|
||
|
||
rcontloop9:
|
||
maccn normalbeg2dc10
|
||
|
||
rcontloop10:
|
||
maccn short normalbeg2dc11
|
||
|
||
rcontloop11:
|
||
maccn short normalbeg2dc12
|
||
|
||
rcontloop12:
|
||
maccn short normalbeg2dc13
|
||
|
||
rcontloop13:
|
||
maccn short normalbeg2dc14
|
||
|
||
rcontloop14:
|
||
maccn short normalbeg2dc15
|
||
|
||
rcontloop15:
|
||
and eax,7fffh
|
||
mov ax,word ptr[esi+eax*2]
|
||
cmp ecx,eax
|
||
jnb exitloop
|
||
|
||
sub chain_length,16
|
||
ja do16
|
||
jmp normalbeg0add16
|
||
|
||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||
|
||
normbeg MACRO rcontlab,valsub
|
||
; if we are here, we know that *(match+best_len-1) == scan_end
|
||
cmp bp,word ptr[edx+eax]
|
||
; if (match != scan_start) goto rcontlab
|
||
jne rcontlab
|
||
; calculate the good chain_length, and we'll compare scan and match string
|
||
add chain_length,16-valsub
|
||
jmp iseq
|
||
ENDM
|
||
|
||
|
||
normalbeg2dc11:
|
||
normbeg rcontloop11,11
|
||
|
||
normalbeg2dc12:
|
||
normbeg short rcontloop12,12
|
||
|
||
normalbeg2dc13:
|
||
normbeg short rcontloop13,13
|
||
|
||
normalbeg2dc14:
|
||
normbeg short rcontloop14,14
|
||
|
||
normalbeg2dc15:
|
||
normbeg short rcontloop15,15
|
||
|
||
normalbeg2dc10:
|
||
normbeg rcontloop10,10
|
||
|
||
normalbeg2dc9:
|
||
normbeg rcontloop9,9
|
||
|
||
normalbeg2dc8:
|
||
normbeg rcontloop8,8
|
||
|
||
normalbeg2dc7:
|
||
normbeg rcontloop7,7
|
||
|
||
normalbeg2dc6:
|
||
normbeg rcontloop6,6
|
||
|
||
normalbeg2dc5:
|
||
normbeg rcontloop5,5
|
||
|
||
normalbeg2dc4:
|
||
normbeg rcontloop4,4
|
||
|
||
normalbeg2dc3:
|
||
normbeg rcontloop3,3
|
||
|
||
normalbeg2dc2:
|
||
normbeg rcontloop2,2
|
||
|
||
normalbeg2dc1:
|
||
normbeg rcontloop1,1
|
||
|
||
normalbeg2dc0:
|
||
normbeg rcontloop0,0
|
||
|
||
|
||
; we go in normalbeg2 because *(ushf*)(match+best_len-1) == scan_end
|
||
|
||
normalbeg2:
|
||
mov edi,window
|
||
|
||
cmp bp,word ptr[edi+eax]
|
||
jne contloop3 ; if *(ushf*)match != scan_start, continue
|
||
|
||
iseq:
|
||
; if we are here, we know that *(match+best_len-1) == scan_end
|
||
; and (match == scan_start)
|
||
|
||
mov edi,edx
|
||
mov esi,scan ; esi = scan
|
||
add edi,eax ; edi = window + cur_match = match
|
||
|
||
mov edx,[esi+3] ; compare manually dword at match+3
|
||
xor edx,[edi+3] ; and scan +3
|
||
|
||
jz begincompare ; if equal, go to long compare
|
||
|
||
; we will determine the unmatch byte and calculate len (in esi)
|
||
or dl,dl
|
||
je eq1rr
|
||
mov esi,3
|
||
jmp trfinval
|
||
eq1rr:
|
||
or dx,dx
|
||
je eq1
|
||
|
||
mov esi,4
|
||
jmp trfinval
|
||
eq1:
|
||
and edx,0ffffffh
|
||
jz eq11
|
||
mov esi,5
|
||
jmp trfinval
|
||
eq11:
|
||
mov esi,6
|
||
jmp trfinval
|
||
|
||
begincompare:
|
||
; here we now scan and match begin same
|
||
add edi,6
|
||
add esi,6
|
||
mov ecx,(MAX_MATCH-(2+4))/4 ; scan for at most MAX_MATCH bytes
|
||
repe cmpsd ; loop until mismatch
|
||
|
||
je trfin ; go to trfin if not unmatch
|
||
; we determine the unmatch byte
|
||
sub esi,4
|
||
mov edx,[edi-4]
|
||
xor edx,[esi]
|
||
|
||
or dl,dl
|
||
jnz trfin
|
||
inc esi
|
||
|
||
or dx,dx
|
||
jnz trfin
|
||
inc esi
|
||
|
||
and edx,0ffffffh
|
||
jnz trfin
|
||
inc esi
|
||
|
||
trfin:
|
||
sub esi,scan ; esi = len
|
||
trfinval:
|
||
; here we have finised compare, and esi contain len of equal string
|
||
cmp esi,best_len ; if len > best_len, go newbestlen
|
||
ja short newbestlen
|
||
; now we restore edx, ecx and esi, for the big loop
|
||
mov esi,prev
|
||
mov ecx,limit
|
||
mov edx,window
|
||
jmp contloop3
|
||
|
||
newbestlen:
|
||
mov best_len,esi ; len become best_len
|
||
|
||
mov match_start,eax ; save new position as match_start
|
||
cmp esi,nice_match ; if best_len >= nice_match, exit
|
||
jae exitloop
|
||
mov ecx,scan
|
||
mov edx,window ; restore edx=window
|
||
add ecx,esi
|
||
add esi,edx
|
||
|
||
dec esi
|
||
mov windowlen,esi ; windowlen = window + best_len-1
|
||
mov bx,[ecx-1] ; bx = *(scan+best_len-1) = scan_end
|
||
|
||
; now we restore ecx and esi, for the big loop :
|
||
mov esi,prev
|
||
mov ecx,limit
|
||
jmp contloop3
|
||
|
||
exitloop:
|
||
; exit : s->match_start=match_start
|
||
mov ebx,match_start
|
||
mov ebp,str_s
|
||
mov ecx,best_len
|
||
mov dword ptr [ebp+dep_match_start],ebx
|
||
mov eax,dword ptr [ebp+dep_lookahead]
|
||
cmp ecx,eax
|
||
ja minexlo
|
||
mov eax,ecx
|
||
minexlo:
|
||
; return min(best_len,s->lookahead)
|
||
|
||
; restore stack and register ebx,esi,edi,ebp
|
||
add esp,NbStackAdd
|
||
|
||
pop ebx
|
||
pop esi
|
||
pop edi
|
||
pop ebp
|
||
ret
|
||
InfoAuthor:
|
||
; please don't remove this string !
|
||
; Your are free use gvmat32 in any fre or commercial apps if you don't remove the string in the binary!
|
||
db 0dh,0ah,"GVMat32 optimised assembly code written 1996-98 by Gilles Vollant",0dh,0ah
|
||
|
||
|
||
|
||
IFDEF NOUNDERLINE
|
||
longest_match_7fff endp
|
||
ELSE
|
||
_longest_match_7fff endp
|
||
ENDIF
|
||
|
||
|
||
IFDEF NOUNDERLINE
|
||
cpudetect32 proc near
|
||
ELSE
|
||
_cpudetect32 proc near
|
||
ENDIF
|
||
|
||
push ebx
|
||
|
||
pushfd ; push original EFLAGS
|
||
pop eax ; get original EFLAGS
|
||
mov ecx, eax ; save original EFLAGS
|
||
xor eax, 40000h ; flip AC bit in EFLAGS
|
||
push eax ; save new EFLAGS value on stack
|
||
popfd ; replace current EFLAGS value
|
||
pushfd ; get new EFLAGS
|
||
pop eax ; store new EFLAGS in EAX
|
||
xor eax, ecx ; can<61>t toggle AC bit, processor=80386
|
||
jz end_cpu_is_386 ; jump if 80386 processor
|
||
push ecx
|
||
popfd ; restore AC bit in EFLAGS first
|
||
|
||
pushfd
|
||
pushfd
|
||
pop ecx
|
||
|
||
mov eax, ecx ; get original EFLAGS
|
||
xor eax, 200000h ; flip ID bit in EFLAGS
|
||
push eax ; save new EFLAGS value on stack
|
||
popfd ; replace current EFLAGS value
|
||
pushfd ; get new EFLAGS
|
||
pop eax ; store new EFLAGS in EAX
|
||
popfd ; restore original EFLAGS
|
||
xor eax, ecx ; can<61>t toggle ID bit,
|
||
je is_old_486 ; processor=old
|
||
|
||
mov eax,1
|
||
db 0fh,0a2h ;CPUID
|
||
|
||
exitcpudetect:
|
||
pop ebx
|
||
ret
|
||
|
||
end_cpu_is_386:
|
||
mov eax,0300h
|
||
jmp exitcpudetect
|
||
|
||
is_old_486:
|
||
mov eax,0400h
|
||
jmp exitcpudetect
|
||
|
||
IFDEF NOUNDERLINE
|
||
cpudetect32 endp
|
||
ELSE
|
||
_cpudetect32 endp
|
||
ENDIF
|
||
|
||
|
||
|
||
|
||
MAX_MATCH equ 258
|
||
MIN_MATCH equ 3
|
||
MIN_LOOKAHEAD equ (MAX_MATCH + MIN_MATCH + 1)
|
||
MAX_MATCH_8_ equ ((MAX_MATCH + 7) AND 0FFF0h)
|
||
|
||
|
||
;;; stack frame offsets
|
||
|
||
chainlenwmask equ esp + 0 ; high word: current chain len
|
||
; low word: s->wmask
|
||
window equ esp + 4 ; local copy of s->window
|
||
windowbestlen equ esp + 8 ; s->window + bestlen
|
||
scanstart equ esp + 16 ; first two bytes of string
|
||
scanend equ esp + 12 ; last two bytes of string
|
||
scanalign equ esp + 20 ; dword-misalignment of string
|
||
nicematch equ esp + 24 ; a good enough match size
|
||
bestlen equ esp + 28 ; size of best match so far
|
||
scan equ esp + 32 ; ptr to string wanting match
|
||
|
||
LocalVarsSize equ 36
|
||
; saved ebx byte esp + 36
|
||
; saved edi byte esp + 40
|
||
; saved esi byte esp + 44
|
||
; saved ebp byte esp + 48
|
||
; return address byte esp + 52
|
||
deflatestate equ esp + 56 ; the function arguments
|
||
curmatch equ esp + 60
|
||
|
||
;;; Offsets for fields in the deflate_state structure. These numbers
|
||
;;; are calculated from the definition of deflate_state, with the
|
||
;;; assumption that the compiler will dword-align the fields. (Thus,
|
||
;;; changing the definition of deflate_state could easily cause this
|
||
;;; program to crash horribly, without so much as a warning at
|
||
;;; compile time. Sigh.)
|
||
|
||
dsWSize equ 36
|
||
dsWMask equ 44
|
||
dsWindow equ 48
|
||
dsPrev equ 56
|
||
dsMatchLen equ 88
|
||
dsPrevMatch equ 92
|
||
dsStrStart equ 100
|
||
dsMatchStart equ 104
|
||
dsLookahead equ 108
|
||
dsPrevLen equ 112
|
||
dsMaxChainLen equ 116
|
||
dsGoodMatch equ 132
|
||
dsNiceMatch equ 136
|
||
|
||
|
||
;;; match.asm -- Pentium-Pro-optimized version of longest_match()
|
||
;;; Written for zlib 1.1.2
|
||
;;; Copyright (C) 1998 Brian Raiter <breadbox@muppetlabs.com>
|
||
;;; You can look at http://www.muppetlabs.com/~breadbox/software/assembly.html
|
||
;;;
|
||
;;; This is free software; you can redistribute it and/or modify it
|
||
;;; under the terms of the GNU General Public License.
|
||
|
||
;GLOBAL _longest_match, _match_init
|
||
|
||
|
||
;SECTION .text
|
||
|
||
;;; uInt longest_match(deflate_state *deflatestate, IPos curmatch)
|
||
|
||
;_longest_match:
|
||
IFDEF NOUNDERLINE
|
||
longest_match_686 proc near
|
||
ELSE
|
||
_longest_match_686 proc near
|
||
ENDIF
|
||
|
||
|
||
;;; Save registers that the compiler may be using, and adjust esp to
|
||
;;; make room for our stack frame.
|
||
|
||
push ebp
|
||
push edi
|
||
push esi
|
||
push ebx
|
||
sub esp, LocalVarsSize
|
||
|
||
;;; Retrieve the function arguments. ecx will hold cur_match
|
||
;;; throughout the entire function. edx will hold the pointer to the
|
||
;;; deflate_state structure during the function's setup (before
|
||
;;; entering the main loop.
|
||
|
||
mov edx, [deflatestate]
|
||
mov ecx, [curmatch]
|
||
|
||
;;; uInt wmask = s->w_mask;
|
||
;;; unsigned chain_length = s->max_chain_length;
|
||
;;; if (s->prev_length >= s->good_match) {
|
||
;;; chain_length >>= 2;
|
||
;;; }
|
||
|
||
mov eax, [edx + dsPrevLen]
|
||
mov ebx, [edx + dsGoodMatch]
|
||
cmp eax, ebx
|
||
mov eax, [edx + dsWMask]
|
||
mov ebx, [edx + dsMaxChainLen]
|
||
jl LastMatchGood
|
||
shr ebx, 2
|
||
LastMatchGood:
|
||
|
||
;;; chainlen is decremented once beforehand so that the function can
|
||
;;; use the sign flag instead of the zero flag for the exit test.
|
||
;;; It is then shifted into the high word, to make room for the wmask
|
||
;;; value, which it will always accompany.
|
||
|
||
dec ebx
|
||
shl ebx, 16
|
||
or ebx, eax
|
||
mov [chainlenwmask], ebx
|
||
|
||
;;; if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
|
||
|
||
mov eax, [edx + dsNiceMatch]
|
||
mov ebx, [edx + dsLookahead]
|
||
cmp ebx, eax
|
||
jl LookaheadLess
|
||
mov ebx, eax
|
||
LookaheadLess: mov [nicematch], ebx
|
||
|
||
;;; register Bytef *scan = s->window + s->strstart;
|
||
|
||
mov esi, [edx + dsWindow]
|
||
mov [window], esi
|
||
mov ebp, [edx + dsStrStart]
|
||
lea edi, [esi + ebp]
|
||
mov [scan], edi
|
||
|
||
;;; Determine how many bytes the scan ptr is off from being
|
||
;;; dword-aligned.
|
||
|
||
mov eax, edi
|
||
neg eax
|
||
and eax, 3
|
||
mov [scanalign], eax
|
||
|
||
;;; IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
|
||
;;; s->strstart - (IPos)MAX_DIST(s) : NIL;
|
||
|
||
mov eax, [edx + dsWSize]
|
||
sub eax, MIN_LOOKAHEAD
|
||
sub ebp, eax
|
||
jg LimitPositive
|
||
xor ebp, ebp
|
||
LimitPositive:
|
||
|
||
;;; int best_len = s->prev_length;
|
||
|
||
mov eax, [edx + dsPrevLen]
|
||
mov [bestlen], eax
|
||
|
||
;;; Store the sum of s->window + best_len in esi locally, and in esi.
|
||
|
||
add esi, eax
|
||
mov [windowbestlen], esi
|
||
|
||
;;; register ush scan_start = *(ushf*)scan;
|
||
;;; register ush scan_end = *(ushf*)(scan+best_len-1);
|
||
;;; Posf *prev = s->prev;
|
||
|
||
movzx ebx, word ptr [edi]
|
||
mov [scanstart], ebx
|
||
movzx ebx, word ptr [edi + eax - 1]
|
||
mov [scanend], ebx
|
||
mov edi, [edx + dsPrev]
|
||
|
||
;;; Jump into the main loop.
|
||
|
||
mov edx, [chainlenwmask]
|
||
jmp short LoopEntry
|
||
|
||
align 4
|
||
|
||
;;; do {
|
||
;;; match = s->window + cur_match;
|
||
;;; if (*(ushf*)(match+best_len-1) != scan_end ||
|
||
;;; *(ushf*)match != scan_start) continue;
|
||
;;; [...]
|
||
;;; } while ((cur_match = prev[cur_match & wmask]) > limit
|
||
;;; && --chain_length != 0);
|
||
;;;
|
||
;;; Here is the inner loop of the function. The function will spend the
|
||
;;; majority of its time in this loop, and majority of that time will
|
||
;;; be spent in the first ten instructions.
|
||
;;;
|
||
;;; Within this loop:
|
||
;;; ebx = scanend
|
||
;;; ecx = curmatch
|
||
;;; edx = chainlenwmask - i.e., ((chainlen << 16) | wmask)
|
||
;;; esi = windowbestlen - i.e., (window + bestlen)
|
||
;;; edi = prev
|
||
;;; ebp = limit
|
||
|
||
LookupLoop:
|
||
and ecx, edx
|
||
movzx ecx, word ptr [edi + ecx*2]
|
||
cmp ecx, ebp
|
||
jbe LeaveNow
|
||
sub edx, 00010000h
|
||
js LeaveNow
|
||
LoopEntry: movzx eax, word ptr [esi + ecx - 1]
|
||
cmp eax, ebx
|
||
jnz LookupLoop
|
||
mov eax, [window]
|
||
movzx eax, word ptr [eax + ecx]
|
||
cmp eax, [scanstart]
|
||
jnz LookupLoop
|
||
|
||
;;; Store the current value of chainlen.
|
||
|
||
mov [chainlenwmask], edx
|
||
|
||
;;; Point edi to the string under scrutiny, and esi to the string we
|
||
;;; are hoping to match it up with. In actuality, esi and edi are
|
||
;;; both pointed (MAX_MATCH_8 - scanalign) bytes ahead, and edx is
|
||
;;; initialized to -(MAX_MATCH_8 - scanalign).
|
||
|
||
mov esi, [window]
|
||
mov edi, [scan]
|
||
add esi, ecx
|
||
mov eax, [scanalign]
|
||
mov edx, 0fffffef8h; -(MAX_MATCH_8)
|
||
lea edi, [edi + eax + 0108h] ;MAX_MATCH_8]
|
||
lea esi, [esi + eax + 0108h] ;MAX_MATCH_8]
|
||
|
||
;;; Test the strings for equality, 8 bytes at a time. At the end,
|
||
;;; adjust edx so that it is offset to the exact byte that mismatched.
|
||
;;;
|
||
;;; We already know at this point that the first three bytes of the
|
||
;;; strings match each other, and they can be safely passed over before
|
||
;;; starting the compare loop. So what this code does is skip over 0-3
|
||
;;; bytes, as much as necessary in order to dword-align the edi
|
||
;;; pointer. (esi will still be misaligned three times out of four.)
|
||
;;;
|
||
;;; It should be confessed that this loop usually does not represent
|
||
;;; much of the total running time. Replacing it with a more
|
||
;;; straightforward "rep cmpsb" would not drastically degrade
|
||
;;; performance.
|
||
|
||
LoopCmps:
|
||
mov eax, [esi + edx]
|
||
xor eax, [edi + edx]
|
||
jnz LeaveLoopCmps
|
||
mov eax, [esi + edx + 4]
|
||
xor eax, [edi + edx + 4]
|
||
jnz LeaveLoopCmps4
|
||
add edx, 8
|
||
jnz LoopCmps
|
||
jmp short LenMaximum
|
||
LeaveLoopCmps4: add edx, 4
|
||
LeaveLoopCmps: test eax, 0000FFFFh
|
||
jnz LenLower
|
||
add edx, 2
|
||
shr eax, 16
|
||
LenLower: sub al, 1
|
||
adc edx, 0
|
||
|
||
;;; Calculate the length of the match. If it is longer than MAX_MATCH,
|
||
;;; then automatically accept it as the best possible match and leave.
|
||
|
||
lea eax, [edi + edx]
|
||
mov edi, [scan]
|
||
sub eax, edi
|
||
cmp eax, MAX_MATCH
|
||
jge LenMaximum
|
||
|
||
;;; If the length of the match is not longer than the best match we
|
||
;;; have so far, then forget it and return to the lookup loop.
|
||
|
||
mov edx, [deflatestate]
|
||
mov ebx, [bestlen]
|
||
cmp eax, ebx
|
||
jg LongerMatch
|
||
mov esi, [windowbestlen]
|
||
mov edi, [edx + dsPrev]
|
||
mov ebx, [scanend]
|
||
mov edx, [chainlenwmask]
|
||
jmp LookupLoop
|
||
|
||
;;; s->match_start = cur_match;
|
||
;;; best_len = len;
|
||
;;; if (len >= nice_match) break;
|
||
;;; scan_end = *(ushf*)(scan+best_len-1);
|
||
|
||
LongerMatch: mov ebx, [nicematch]
|
||
mov [bestlen], eax
|
||
mov [edx + dsMatchStart], ecx
|
||
cmp eax, ebx
|
||
jge LeaveNow
|
||
mov esi, [window]
|
||
add esi, eax
|
||
mov [windowbestlen], esi
|
||
movzx ebx, word ptr [edi + eax - 1]
|
||
mov edi, [edx + dsPrev]
|
||
mov [scanend], ebx
|
||
mov edx, [chainlenwmask]
|
||
jmp LookupLoop
|
||
|
||
;;; Accept the current string, with the maximum possible length.
|
||
|
||
LenMaximum: mov edx, [deflatestate]
|
||
mov dword ptr [bestlen], MAX_MATCH
|
||
mov [edx + dsMatchStart], ecx
|
||
|
||
;;; if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
|
||
;;; return s->lookahead;
|
||
|
||
LeaveNow:
|
||
mov edx, [deflatestate]
|
||
mov ebx, [bestlen]
|
||
mov eax, [edx + dsLookahead]
|
||
cmp ebx, eax
|
||
jg LookaheadRet
|
||
mov eax, ebx
|
||
LookaheadRet:
|
||
|
||
;;; Restore the stack and return from whence we came.
|
||
|
||
add esp, LocalVarsSize
|
||
pop ebx
|
||
pop esi
|
||
pop edi
|
||
pop ebp
|
||
|
||
ret
|
||
; please don't remove this string !
|
||
; Your are free use gvmat32 in any fre or commercial apps if you don't remove the string in the binary!
|
||
db 0dh,0ah,"asm686 with masm, code optimised assembly code from Brian Raiter, written 1998",0dh,0ah
|
||
|
||
IFDEF NOUNDERLINE
|
||
longest_match_686 endp
|
||
ELSE
|
||
_longest_match_686 endp
|
||
ENDIF
|
||
|
||
_TEXT ends
|
||
end
|