diff options
Diffstat (limited to 'cpukit/zlib/contrib/masmx86/gvmat32.asm')
| -rw-r--r-- | cpukit/zlib/contrib/masmx86/gvmat32.asm | 1881 |
1 files changed, 972 insertions, 909 deletions
diff --git a/cpukit/zlib/contrib/masmx86/gvmat32.asm b/cpukit/zlib/contrib/masmx86/gvmat32.asm index e841a7fda2..874bb2d482 100644 --- a/cpukit/zlib/contrib/masmx86/gvmat32.asm +++ b/cpukit/zlib/contrib/masmx86/gvmat32.asm @@ -1,909 +1,972 @@ -; -; 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 +addstr offsets are due to the addition of pending_buf_size in zlib 1.04 -; and adding gzhead and gzindex in zlib 1.2.2.1 -; in the deflate_state structure since the asm code was first written -; (if you compile with zlib 1.0.4 or older, set addstr to 0). -; (if you compiler with zlib between 1.04 and 1.2.1, set addstr to 4) -; Note : these value are good with a 8 bytes boundary pack structure - - addstr equ 4+8 - dep_chain_length equ 70h+addstr - dep_window equ 2ch+addstr - dep_strstart equ 60h+addstr - dep_prev_length equ 6ch+addstr - dep_nice_match equ 84h+addstr - dep_w_size equ 20h+addstr - dep_prev equ 34h+addstr - dep_w_mask equ 28h+addstr - dep_good_match equ 80h+addstr - dep_match_start equ 64h+addstr - dep_lookahead equ 68h+addstr - - -_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’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’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+addstr-4 -dsWMask equ 44+addstr-4 -dsWindow equ 48+addstr-4 -dsPrev equ 56+addstr-4 -dsMatchLen equ 88+addstr-4 -dsPrevMatch equ 92+addstr-4 -dsStrStart equ 100+addstr-4 -dsMatchStart equ 104+addstr-4 -dsLookahead equ 108+addstr-4 -dsPrevLen equ 112+addstr-4 -dsMaxChainLen equ 116+addstr-4 -dsGoodMatch equ 132+addstr-4 -dsNiceMatch equ 136+addstr-4 - - -;;; 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 can freely use gvmat32 in any free or commercial app if you don't remove the string in the binary! - db 0dh,0ah,"asm686 with masm, 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 +; 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
+;
+; http://www.zlib.net
+; http://www.winimage.com/zLibDll
+; http://www.muppetlabs.com/~breadbox/software/assembly.html
+;
+; For Visual C++ 4.x and higher and ML 6.x and higher
+; ml.exe is in directory \MASM611C of Win95 DDK
+; ml.exe is also distributed in http://www.masm32.com/masmdl.htm
+; and in VC++2003 toolkit at http://msdn.microsoft.com/visualc/vctoolkit2003/
+;
+; this file contain two implementation of longest_match
+;
+; longest_match_7fff : written 1996 by Gilles Vollant optimized for
+; first Pentium. Assume s->w_mask == 0x7fff
+; longest_match_686 : written by Brian raiter (1998), optimized for Pentium Pro
+;
+; for using an seembly version of longest_match, you need define ASMV in project
+; There is two way in using gvmat32.asm
+;
+; A) Suggested method
+; if you want include both longest_match_7fff and longest_match_686
+; compile the asm file running
+; ml /coff /Zi /Flgvmat32.lst /c gvmat32.asm
+; and include gvmat32c.c in your project
+; if you have an old cpu (386,486 or first Pentium) and s->w_mask==0x7fff,
+; longest_match_7fff will be used
+; if you have a more modern CPU (Pentium Pro, II and higher)
+; longest_match_686 will be used
+; on old cpu with s->w_mask!=0x7fff, longest_match_686 will be used,
+; but this is not a sitation you'll find often
+;
+; B) Alternative
+; if you are not interresed in old cpu performance and want the smaller
+; binaries possible
+;
+; compile the asm file running
+; ml /coff /Zi /c /Flgvmat32.lst /DNOOLDPENTIUMCODE gvmat32.asm
+; and do not include gvmat32c.c in your project (ou define also
+; NOOLDPENTIUMCODE)
+;
+; note : as I known, longest_match_686 is very faster than longest_match_7fff
+; on pentium Pro/II/III, faster (but less) in P4, but it seem
+; longest_match_7fff can be faster (very very litte) on AMD Athlon64/K8
+;
+; see below : zlib1222add must be adjuster if you use a zlib version < 1.2.2.2
+
+;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 +zlib1222add offsets are due to the addition of fields
+; in zlib in the deflate_state structure since the asm code was first written
+; (if you compile with zlib 1.0.4 or older, use "zlib1222add equ (-4)").
+; (if you compile with zlib between 1.0.5 and 1.2.2.1, use "zlib1222add equ 0").
+; if you compile with zlib 1.2.2.2 or later , use "zlib1222add equ 8").
+
+ zlib1222add equ 8
+
+; Note : these value are good with a 8 bytes boundary pack structure
+ dep_chain_length equ 74h+zlib1222add
+ dep_window equ 30h+zlib1222add
+ dep_strstart equ 64h+zlib1222add
+ dep_prev_length equ 70h+zlib1222add
+ dep_nice_match equ 88h+zlib1222add
+ dep_w_size equ 24h+zlib1222add
+ dep_prev equ 38h+zlib1222add
+ dep_w_mask equ 2ch+zlib1222add
+ dep_good_match equ 84h+zlib1222add
+ dep_match_start equ 68h+zlib1222add
+ dep_lookahead equ 6ch+zlib1222add
+
+
+_TEXT segment
+
+IFDEF NOUNDERLINE
+ IFDEF NOOLDPENTIUMCODE
+ public longest_match
+ public match_init
+ ELSE
+ public longest_match_7fff
+ public cpudetect32
+ public longest_match_686
+ ENDIF
+ELSE
+ IFDEF NOOLDPENTIUMCODE
+ public _longest_match
+ public _match_init
+ ELSE
+ public _longest_match_7fff
+ public _cpudetect32
+ public _longest_match_686
+ ENDIF
+ENDIF
+
+ MAX_MATCH equ 258
+ MIN_MATCH equ 3
+ MIN_LOOKAHEAD equ (MAX_MATCH+MIN_MATCH+1)
+
+
+
+IFNDEF NOOLDPENTIUMCODE
+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’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’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
+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+zlib1222add
+dsWMask equ 44+zlib1222add
+dsWindow equ 48+zlib1222add
+dsPrev equ 56+zlib1222add
+dsMatchLen equ 88+zlib1222add
+dsPrevMatch equ 92+zlib1222add
+dsStrStart equ 100+zlib1222add
+dsMatchStart equ 104+zlib1222add
+dsLookahead equ 108+zlib1222add
+dsPrevLen equ 112+zlib1222add
+dsMaxChainLen equ 116+zlib1222add
+dsGoodMatch equ 132+zlib1222add
+dsNiceMatch equ 136+zlib1222add
+
+
+;;; 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 NOOLDPENTIUMCODE
+ IFDEF NOUNDERLINE
+ longest_match proc near
+ ELSE
+ _longest_match proc near
+ ENDIF
+ELSE
+ IFDEF NOUNDERLINE
+ longest_match_686 proc near
+ ELSE
+ _longest_match_686 proc near
+ ENDIF
+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 can freely use gvmat32 in any free or commercial app if you don't remove the string in the binary!
+ db 0dh,0ah,"asm686 with masm, optimised assembly code from Brian Raiter, written 1998",0dh,0ah
+
+
+IFDEF NOOLDPENTIUMCODE
+ IFDEF NOUNDERLINE
+ longest_match endp
+ ELSE
+ _longest_match endp
+ ENDIF
+
+ IFDEF NOUNDERLINE
+ match_init proc near
+ ret
+ match_init endp
+ ELSE
+ _match_init proc near
+ ret
+ _match_init endp
+ ENDIF
+ELSE
+ IFDEF NOUNDERLINE
+ longest_match_686 endp
+ ELSE
+ _longest_match_686 endp
+ ENDIF
+ENDIF
+
+_TEXT ends
+end
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