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author | nijtmans <nijtmans> | 2010-04-20 14:50:10 (GMT) |
---|---|---|
committer | nijtmans <nijtmans> | 2010-04-20 14:50:10 (GMT) |
commit | 833ea84043d927c416802983797aa3884a894012 (patch) | |
tree | 92c8f9663c828bd3eb7d42c72b7b54841ed193ab /compat/zlib/contrib/masmx86/match686.asm | |
parent | 04890d3f2b3093debd335e9bea71a39c99a9fa5e (diff) | |
download | tcl-833ea84043d927c416802983797aa3884a894012.zip tcl-833ea84043d927c416802983797aa3884a894012.tar.gz tcl-833ea84043d927c416802983797aa3884a894012.tar.bz2 |
Upgrade to zlib 1.2.5
Diffstat (limited to 'compat/zlib/contrib/masmx86/match686.asm')
-rw-r--r-- | compat/zlib/contrib/masmx86/match686.asm | 956 |
1 files changed, 478 insertions, 478 deletions
diff --git a/compat/zlib/contrib/masmx86/match686.asm b/compat/zlib/contrib/masmx86/match686.asm index 21ae704..1eaf555 100644 --- a/compat/zlib/contrib/masmx86/match686.asm +++ b/compat/zlib/contrib/masmx86/match686.asm @@ -1,478 +1,478 @@ -; match686.asm -- Asm portion of the optimized longest_match for 32 bits x86 -; Copyright (C) 1995-1996 Jean-loup Gailly, Brian Raiter and Gilles Vollant. -; File written by Gilles Vollant, by converting match686.S from Brian Raiter -; for MASM. This is as assembly version of 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 distributed in -; http://www.microsoft.com/downloads/details.aspx?FamilyID=7a1c9da0-0510-44a2-b042-7ef370530c64 -; -; this file contain two implementation of longest_match -; -; this longest_match was written by Brian raiter (1998), optimized for Pentium Pro -; (and the faster known version of match_init on modern Core 2 Duo and AMD Phenom) -; -; for using an assembly version of longest_match, you need define ASMV in project -; -; compile the asm file running -; ml /coff /Zi /c /Flmatch686.lst match686.asm -; and do not include match686.obj in your project -; -; note: contrib of zLib 1.2.3 and earlier contained both a deprecated version for -; Pentium (prior Pentium Pro) and this version for Pentium Pro and modern processor -; with autoselect (with cpu detection code) -; if you want support the old pentium optimization, you can still use these version -; -; this file is not optimized for old pentium, but it compatible with all x86 32 bits -; processor (starting 80386) -; -; -; see below : zlib1222add must be adjuster if you use a zlib version < 1.2.2.2 - -;uInt longest_match(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 - public longest_match - public match_init -ELSE - public _longest_match - public _match_init -ENDIF - - MAX_MATCH equ 258 - MIN_MATCH equ 3 - MIN_LOOKAHEAD equ (MAX_MATCH+MIN_MATCH+1) - - - -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 - - -;;; match686.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 software is provided 'as-is', without any express or implied -;; warranty. In no event will the authors be held liable for any damages -;; arising from the use of this software. -;; -;; Permission is granted to anyone to use this software for any purpose, -;; including commercial applications, and to alter it and redistribute it -;; freely, subject to the following restrictions: -;; -;; 1. The origin of this software must not be misrepresented; you must not -;; claim that you wrote the original software. If you use this software -;; in a product, an acknowledgment in the product documentation would be -;; appreciated but is not required. -;; 2. Altered source versions must be plainly marked as such, and must not be -;; misrepresented as being the original software -;; 3. This notice may not be removed or altered from any source distribution. -;; - -;GLOBAL _longest_match, _match_init - - -;SECTION .text - -;;; uInt longest_match(deflate_state *deflatestate, IPos curmatch) - -;_longest_match: - IFDEF NOUNDERLINE - longest_match proc near - ELSE - _longest_match 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 match686 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 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 - - -_TEXT ends -end +; match686.asm -- Asm portion of the optimized longest_match for 32 bits x86
+; Copyright (C) 1995-1996 Jean-loup Gailly, Brian Raiter and Gilles Vollant.
+; File written by Gilles Vollant, by converting match686.S from Brian Raiter
+; for MASM. This is as assembly version of 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 distributed in
+; http://www.microsoft.com/downloads/details.aspx?FamilyID=7a1c9da0-0510-44a2-b042-7ef370530c64
+;
+; this file contain two implementation of longest_match
+;
+; this longest_match was written by Brian raiter (1998), optimized for Pentium Pro
+; (and the faster known version of match_init on modern Core 2 Duo and AMD Phenom)
+;
+; for using an assembly version of longest_match, you need define ASMV in project
+;
+; compile the asm file running
+; ml /coff /Zi /c /Flmatch686.lst match686.asm
+; and do not include match686.obj in your project
+;
+; note: contrib of zLib 1.2.3 and earlier contained both a deprecated version for
+; Pentium (prior Pentium Pro) and this version for Pentium Pro and modern processor
+; with autoselect (with cpu detection code)
+; if you want support the old pentium optimization, you can still use these version
+;
+; this file is not optimized for old pentium, but it compatible with all x86 32 bits
+; processor (starting 80386)
+;
+;
+; see below : zlib1222add must be adjuster if you use a zlib version < 1.2.2.2
+
+;uInt longest_match(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
+ public longest_match
+ public match_init
+ELSE
+ public _longest_match
+ public _match_init
+ENDIF
+
+ MAX_MATCH equ 258
+ MIN_MATCH equ 3
+ MIN_LOOKAHEAD equ (MAX_MATCH+MIN_MATCH+1)
+
+
+
+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
+
+
+;;; match686.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 software is provided 'as-is', without any express or implied
+;; warranty. In no event will the authors be held liable for any damages
+;; arising from the use of this software.
+;;
+;; Permission is granted to anyone to use this software for any purpose,
+;; including commercial applications, and to alter it and redistribute it
+;; freely, subject to the following restrictions:
+;;
+;; 1. The origin of this software must not be misrepresented; you must not
+;; claim that you wrote the original software. If you use this software
+;; in a product, an acknowledgment in the product documentation would be
+;; appreciated but is not required.
+;; 2. Altered source versions must be plainly marked as such, and must not be
+;; misrepresented as being the original software
+;; 3. This notice may not be removed or altered from any source distribution.
+;;
+
+;GLOBAL _longest_match, _match_init
+
+
+;SECTION .text
+
+;;; uInt longest_match(deflate_state *deflatestate, IPos curmatch)
+
+;_longest_match:
+ IFDEF NOUNDERLINE
+ longest_match proc near
+ ELSE
+ _longest_match 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 match686 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 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
+
+
+_TEXT ends
+end
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