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; |
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; gvmat32.asm -- Asm portion of the optimized longest_match for 32 bits x86 |
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; Copyright (C) 1995-1996 Jean-loup Gailly and Gilles Vollant. |
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; File written by Gilles Vollant, by modifiying the longest_match |
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; from Jean-loup Gailly in deflate.c |
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; It need wmask == 0x7fff |
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; (assembly code is faster with a fixed wmask) |
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; |
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; For Visual C++ 4.2 and ML 6.11c (version in directory \MASM611C of Win95 DDK) |
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; I compile with : "ml /coff /Zi /c gvmat32.asm" |
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; |
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;uInt longest_match_7fff(s, cur_match) |
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; deflate_state *s; |
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; IPos cur_match; /* current match */ |
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NbStack equ 76 |
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cur_match equ dword ptr[esp+NbStack-0] |
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str_s equ dword ptr[esp+NbStack-4] |
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; 5 dword on top (ret,ebp,esi,edi,ebx) |
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adrret equ dword ptr[esp+NbStack-8] |
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pushebp equ dword ptr[esp+NbStack-12] |
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pushedi equ dword ptr[esp+NbStack-16] |
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pushesi equ dword ptr[esp+NbStack-20] |
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pushebx equ dword ptr[esp+NbStack-24] |
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chain_length equ dword ptr [esp+NbStack-28] |
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limit equ dword ptr [esp+NbStack-32] |
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best_len equ dword ptr [esp+NbStack-36] |
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window equ dword ptr [esp+NbStack-40] |
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prev equ dword ptr [esp+NbStack-44] |
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scan_start equ word ptr [esp+NbStack-48] |
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wmask equ dword ptr [esp+NbStack-52] |
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match_start_ptr equ dword ptr [esp+NbStack-56] |
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nice_match equ dword ptr [esp+NbStack-60] |
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scan equ dword ptr [esp+NbStack-64] |
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windowlen equ dword ptr [esp+NbStack-68] |
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match_start equ dword ptr [esp+NbStack-72] |
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strend equ dword ptr [esp+NbStack-76] |
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NbStackAdd equ (NbStack-24) |
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.386p |
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name gvmatch |
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.MODEL FLAT |
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; all the +4 offsets are due to the addition of pending_buf_size (in zlib |
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; in the deflate_state structure since the asm code was first written |
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; (if you compile with zlib 1.0.4 or older, remove the +4). |
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; Note : these value are good with a 8 bytes boundary pack structure |
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dep_chain_length equ 70h+4 |
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dep_window equ 2ch+4 |
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dep_strstart equ 60h+4 |
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dep_prev_length equ 6ch+4 |
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dep_nice_match equ 84h+4 |
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dep_w_size equ 20h+4 |
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dep_prev equ 34h+4 |
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dep_w_mask equ 28h+4 |
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dep_good_match equ 80h+4 |
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dep_match_start equ 64h+4 |
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dep_lookahead equ 68h+4 |
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_TEXT segment |
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IFDEF NOUNDERLINE |
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public longest_match_7fff |
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public longest_match_686 |
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; public match_init |
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ELSE |
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public _longest_match_7fff |
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public _longest_match_686 |
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; public _match_init |
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ENDIF |
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MAX_MATCH equ 258 |
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MIN_MATCH equ 3 |
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MIN_LOOKAHEAD equ (MAX_MATCH+MIN_MATCH+1) |
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IFDEF NOUNDERLINE |
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;match_init proc near |
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; ret |
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;match_init endp |
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ELSE |
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;_match_init proc near |
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; ret |
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;_match_init endp |
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ENDIF |
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IFDEF NOUNDERLINE |
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longest_match_7fff proc near |
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ELSE |
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_longest_match_7fff proc near |
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ENDIF |
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mov edx,[esp+4] |
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push ebp |
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push edi |
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push esi |
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push ebx |
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sub esp,NbStackAdd |
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; initialize or check the variables used in match.asm. |
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mov ebp,edx |
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; chain_length = s->max_chain_length |
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; if (prev_length>=good_match) chain_length >>= 2 |
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mov edx,[ebp+dep_chain_length] |
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mov ebx,[ebp+dep_prev_length] |
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cmp [ebp+dep_good_match],ebx |
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ja noshr |
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shr edx,2 |
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noshr: |
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; we increment chain_length because in the asm, the --chain_lenght is in the beginning of the loop |
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inc edx |
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mov edi,[ebp+dep_nice_match] |
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mov chain_length,edx |
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mov eax,[ebp+dep_lookahead] |
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cmp eax,edi |
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; if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; |
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jae nolookaheadnicematch |
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mov edi,eax |
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nolookaheadnicematch: |
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; best_len = s->prev_length |
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mov best_len,ebx |
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; window = s->window |
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mov esi,[ebp+dep_window] |
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mov ecx,[ebp+dep_strstart] |
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mov window,esi |
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mov nice_match,edi |
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; scan = window + strstart |
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add esi,ecx |
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mov scan,esi |
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; dx = *window |
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mov dx,word ptr [esi] |
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; bx = *(window+best_len-1) |
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mov bx,word ptr [esi+ebx-1] |
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add esi,MAX_MATCH-1 |
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; scan_start = *scan |
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mov scan_start,dx |
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; strend = scan + MAX_MATCH-1 |
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mov strend,esi |
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; bx = scan_end = *(window+best_len-1) |
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; IPos limit = s->strstart > (IPos)MAX_DIST(s) ? |
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; s->strstart - (IPos)MAX_DIST(s) : NIL; |
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mov esi,[ebp+dep_w_size] |
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sub esi,MIN_LOOKAHEAD |
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; here esi = MAX_DIST(s) |
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sub ecx,esi |
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ja nodist |
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xor ecx,ecx |
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nodist: |
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mov limit,ecx |
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; prev = s->prev |
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mov edx,[ebp+dep_prev] |
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mov prev,edx |
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; |
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mov edx,dword ptr [ebp+dep_match_start] |
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mov bp,scan_start |
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mov eax,cur_match |
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mov match_start,edx |
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mov edx,window |
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mov edi,edx |
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add edi,best_len |
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mov esi,prev |
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dec edi |
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; windowlen = window + best_len -1 |
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mov windowlen,edi |
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jmp beginloop2 |
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align 4 |
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; here, in the loop |
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; eax = ax = cur_match |
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; ecx = limit |
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; bx = scan_end |
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; bp = scan_start |
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; edi = windowlen (window + best_len -1) |
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; esi = prev |
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;// here; chain_length <=16 |
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normalbeg0add16: |
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add chain_length,16 |
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jz exitloop |
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normalbeg0: |
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cmp word ptr[edi+eax],bx |
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je normalbeg2noroll |
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rcontlabnoroll: |
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; cur_match = prev[cur_match & wmask] |
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and eax,7fffh |
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mov ax,word ptr[esi+eax*2] |
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; if cur_match > limit, go to exitloop |
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cmp ecx,eax |
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jnb exitloop |
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; if --chain_length != 0, go to exitloop |
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dec chain_length |
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jnz normalbeg0 |
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jmp exitloop |
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normalbeg2noroll: |
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; if (scan_start==*(cur_match+window)) goto normalbeg2 |
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cmp bp,word ptr[edx+eax] |
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jne rcontlabnoroll |
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jmp normalbeg2 |
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contloop3: |
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mov edi,windowlen |
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; cur_match = prev[cur_match & wmask] |
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and eax,7fffh |
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mov ax,word ptr[esi+eax*2] |
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; if cur_match > limit, go to exitloop |
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cmp ecx,eax |
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jnbexitloopshort1: |
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jnb exitloop |
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; if --chain_length != 0, go to exitloop |
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; begin the main loop |
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beginloop2: |
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sub chain_length,16+1 |
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; if chain_length <=16, don't use the unrolled loop |
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jna normalbeg0add16 |
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do16: |
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cmp word ptr[edi+eax],bx |
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je normalbeg2dc0 |
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maccn MACRO lab |
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and eax,7fffh |
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mov ax,word ptr[esi+eax*2] |
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cmp ecx,eax |
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jnb exitloop |
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cmp word ptr[edi+eax],bx |
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je lab |
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ENDM |
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rcontloop0: |
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maccn normalbeg2dc1 |
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rcontloop1: |
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maccn normalbeg2dc2 |
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rcontloop2: |
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maccn normalbeg2dc3 |
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rcontloop3: |
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maccn normalbeg2dc4 |
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rcontloop4: |
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maccn normalbeg2dc5 |
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rcontloop5: |
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maccn normalbeg2dc6 |
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rcontloop6: |
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maccn normalbeg2dc7 |
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rcontloop7: |
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maccn normalbeg2dc8 |
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rcontloop8: |
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maccn normalbeg2dc9 |
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rcontloop9: |
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maccn normalbeg2dc10 |
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rcontloop10: |
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maccn short normalbeg2dc11 |
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rcontloop11: |
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maccn short normalbeg2dc12 |
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rcontloop12: |
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maccn short normalbeg2dc13 |
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rcontloop13: |
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maccn short normalbeg2dc14 |
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rcontloop14: |
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maccn short normalbeg2dc15 |
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rcontloop15: |
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and eax,7fffh |
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mov ax,word ptr[esi+eax*2] |
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cmp ecx,eax |
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jnb exitloop |
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sub chain_length,16 |
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ja do16 |
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jmp normalbeg0add16 |
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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normbeg MACRO rcontlab,valsub |
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; if we are here, we know that *(match+best_len-1) == scan_end |
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cmp bp,word ptr[edx+eax] |
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; if (match != scan_start) goto rcontlab |
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jne rcontlab |
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; calculate the good chain_length, and we'll compare scan and match string |
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add chain_length,16-valsub |
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jmp iseq |
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ENDM |
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normalbeg2dc11: |
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normbeg rcontloop11,11 |
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normalbeg2dc12: |
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normbeg short rcontloop12,12 |
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normalbeg2dc13: |
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normbeg short rcontloop13,13 |
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normalbeg2dc14: |
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normbeg short rcontloop14,14 |
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normalbeg2dc15: |
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normbeg short rcontloop15,15 |
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normalbeg2dc10: |
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normbeg rcontloop10,10 |
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normalbeg2dc9: |
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normbeg rcontloop9,9 |
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normalbeg2dc8: |
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normbeg rcontloop8,8 |
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normalbeg2dc7: |
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normbeg rcontloop7,7 |
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normalbeg2dc6: |
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normbeg rcontloop6,6 |
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normalbeg2dc5: |
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normbeg rcontloop5,5 |
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normalbeg2dc4: |
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normbeg rcontloop4,4 |
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normalbeg2dc3: |
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normbeg rcontloop3,3 |
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normalbeg2dc2: |
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normbeg rcontloop2,2 |
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normalbeg2dc1: |
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normbeg rcontloop1,1 |
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normalbeg2dc0: |
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normbeg rcontloop0,0 |
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; we go in normalbeg2 because *(ushf*)(match+best_len-1) == scan_end |
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normalbeg2: |
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mov edi,window |
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cmp bp,word ptr[edi+eax] |
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jne contloop3 ; if *(ushf*)match != scan_start, continue |
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iseq: |
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; if we are here, we know that *(match+best_len-1) == scan_end |
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; and (match == scan_start) |
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mov edi,edx |
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mov esi,scan ; esi = scan |
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add edi,eax ; edi = window + cur_match = match |
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mov edx,[esi+3] ; compare manually dword at match+3 |
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xor edx,[edi+3] ; and scan +3 |
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jz begincompare ; if equal, go to long compare |
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; we will determine the unmatch byte and calculate len (in esi) |
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or dl,dl |
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je eq1rr |
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mov esi,3 |
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jmp trfinval |
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eq1rr: |
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or dx,dx |
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je eq1 |
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mov esi,4 |
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jmp trfinval |
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eq1: |
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and edx,0ffffffh |
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jz eq11 |
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mov esi,5 |
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jmp trfinval |
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eq11: |
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mov esi,6 |
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jmp trfinval |
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begincompare: |
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; here we now scan and match begin same |
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add edi,6 |
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add esi,6 |
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mov ecx,(MAX_MATCH-(2+4))/4 ; scan for at most MAX_MATCH bytes |
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repe cmpsd ; loop until mismatch |
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je trfin ; go to trfin if not unmatch |
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; we determine the unmatch byte |
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sub esi,4 |
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mov edx,[edi-4] |
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xor edx,[esi] |
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or dl,dl |
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jnz trfin |
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inc esi |
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or dx,dx |
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jnz trfin |
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inc esi |
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and edx,0ffffffh |
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jnz trfin |
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inc esi |
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trfin: |
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sub esi,scan ; esi = len |
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trfinval: |
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; here we have finised compare, and esi contain len of equal string |
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cmp esi,best_len ; if len > best_len, go newbestlen |
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ja short newbestlen |
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; now we restore edx, ecx and esi, for the big loop |
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mov esi,prev |
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mov ecx,limit |
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mov edx,window |
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jmp contloop3 |
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newbestlen: |
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mov best_len,esi ; len become best_len |
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mov match_start,eax ; save new position as match_start |
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cmp esi,nice_match ; if best_len >= nice_match, exit |
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jae exitloop |
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mov ecx,scan |
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mov edx,window ; restore edx=window |
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add ecx,esi |
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add esi,edx |
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dec esi |
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mov windowlen,esi ; windowlen = window + best_len-1 |
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mov bx,[ecx-1] ; bx = *(scan+best_len-1) = scan_end |
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; now we restore ecx and esi, for the big loop : |
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mov esi,prev |
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mov ecx,limit |
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jmp contloop3 |
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exitloop: |
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; exit : s->match_start=match_start |
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mov ebx,match_start |
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mov ebp,str_s |
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mov ecx,best_len |
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mov dword ptr [ebp+dep_match_start],ebx |
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mov eax,dword ptr [ebp+dep_lookahead] |
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cmp ecx,eax |
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ja minexlo |
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mov eax,ecx |
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minexlo: |
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; return min(best_len,s->lookahead) |
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; restore stack and register ebx,esi,edi,ebp |
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add esp,NbStackAdd |
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pop ebx |
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pop esi |
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pop edi |
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pop ebp |
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ret |
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InfoAuthor: |
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; please don't remove this string ! |
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; Your are free use gvmat32 in any fre or commercial apps if you don't remove the string in the binary! |
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db 0dh,0ah,"GVMat32 optimised assembly code written 1996-98 by Gilles Vollant",0dh,0ah |
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IFDEF NOUNDERLINE |
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longest_match_7fff endp |
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ELSE |
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_longest_match_7fff endp |
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ENDIF |
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IFDEF NOUNDERLINE |
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cpudetect32 proc near |
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ELSE |
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_cpudetect32 proc near |
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ENDIF |
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push ebx |
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pushfd ; push original EFLAGS |
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pop eax ; get original EFLAGS |
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mov ecx, eax ; save original EFLAGS |
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xor eax, 40000h ; flip AC bit in EFLAGS |
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push eax ; save new EFLAGS value on stack |
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popfd ; replace current EFLAGS value |
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pushfd ; get new EFLAGS |
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pop eax ; store new EFLAGS in EAX |
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xor eax, ecx ; can<EFBFBD>t toggle AC bit, processor=80386 |
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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<EFBFBD>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 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
|
|
|
|