📄 gvmat32.asm
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;
; 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
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