1 ; match686.asm -- Asm portion of the optimized longest_match for 32 bits x86 2 ; Copyright (C) 1995-1996 Jean-loup Gailly, Brian Raiter and Gilles Vollant. 3 ; File written by Gilles Vollant, by converting match686.S from Brian Raiter 4 ; for MASM. This is as assembly version of longest_match 5 ; from Jean-loup Gailly in deflate.c 6 ; 7 ; http://www.zlib.net 8 ; http://www.winimage.com/zLibDll 9 ; http://www.muppetlabs.com/~breadbox/software/assembly.html 10 ; 11 ; For Visual C++ 4.x and higher and ML 6.x and higher 12 ; ml.exe is distributed in 13 ; http://www.microsoft.com/downloads/details.aspx?FamilyID=7a1c9da0-0510-44a2-b042-7ef370530c64 14 ; 15 ; this file contain two implementation of longest_match 16 ; 17 ; this longest_match was written by Brian raiter (1998), optimized for Pentium Pro 18 ; (and the faster known version of match_init on modern Core 2 Duo and AMD Phenom) 19 ; 20 ; for using an assembly version of longest_match, you need define ASMV in project 21 ; 22 ; compile the asm file running 23 ; ml /coff /Zi /c /Flmatch686.lst match686.asm 24 ; and do not include match686.obj in your project 25 ; 26 ; note: contrib of zLib 1.2.3 and earlier contained both a deprecated version for 27 ; Pentium (prior Pentium Pro) and this version for Pentium Pro and modern processor 28 ; with autoselect (with cpu detection code) 29 ; if you want support the old pentium optimization, you can still use these version 30 ; 31 ; this file is not optimized for old pentium, but it compatible with all x86 32 bits 32 ; processor (starting 80386) 33 ; 34 ; 35 ; see below : zlib1222add must be adjuster if you use a zlib version < 1.2.2.2 36 37 ;uInt longest_match(s, cur_match) 38 ; deflate_state *s; 39 ; IPos cur_match; /* current match */ 40 41 NbStack equ 76 42 cur_match equ dword ptr[esp+NbStack-0] 43 str_s equ dword ptr[esp+NbStack-4] 44 ; 5 dword on top (ret,ebp,esi,edi,ebx) 45 adrret equ dword ptr[esp+NbStack-8] 46 pushebp equ dword ptr[esp+NbStack-12] 47 pushedi equ dword ptr[esp+NbStack-16] 48 pushesi equ dword ptr[esp+NbStack-20] 49 pushebx equ dword ptr[esp+NbStack-24] 50 51 chain_length equ dword ptr [esp+NbStack-28] 52 limit equ dword ptr [esp+NbStack-32] 53 best_len equ dword ptr [esp+NbStack-36] 54 window equ dword ptr [esp+NbStack-40] 55 prev equ dword ptr [esp+NbStack-44] 56 scan_start equ word ptr [esp+NbStack-48] 57 wmask equ dword ptr [esp+NbStack-52] 58 match_start_ptr equ dword ptr [esp+NbStack-56] 59 nice_match equ dword ptr [esp+NbStack-60] 60 scan equ dword ptr [esp+NbStack-64] 61 62 windowlen equ dword ptr [esp+NbStack-68] 63 match_start equ dword ptr [esp+NbStack-72] 64 strend equ dword ptr [esp+NbStack-76] 65 NbStackAdd equ (NbStack-24) 66 67 .386p 68 69 name gvmatch 70 .MODEL FLAT 71 72 73 74 ; all the +zlib1222add offsets are due to the addition of fields 75 ; in zlib in the deflate_state structure since the asm code was first written 76 ; (if you compile with zlib 1.0.4 or older, use "zlib1222add equ (-4)"). 77 ; (if you compile with zlib between 1.0.5 and 1.2.2.1, use "zlib1222add equ 0"). 78 ; if you compile with zlib 1.2.2.2 or later , use "zlib1222add equ 8"). 79 80 zlib1222add equ 8 81 82 ; Note : these value are good with a 8 bytes boundary pack structure 83 dep_chain_length equ 74h+zlib1222add 84 dep_window equ 30h+zlib1222add 85 dep_strstart equ 64h+zlib1222add 86 dep_prev_length equ 70h+zlib1222add 87 dep_nice_match equ 88h+zlib1222add 88 dep_w_size equ 24h+zlib1222add 89 dep_prev equ 38h+zlib1222add 90 dep_w_mask equ 2ch+zlib1222add 91 dep_good_match equ 84h+zlib1222add 92 dep_match_start equ 68h+zlib1222add 93 dep_lookahead equ 6ch+zlib1222add 94 95 96 _TEXT segment 97 98 IFDEF NOUNDERLINE 99 public longest_match 100 public match_init 101 ELSE 102 public _longest_match 103 public _match_init 104 ENDIF 105 106 MAX_MATCH equ 258 107 MIN_MATCH equ 3 108 MIN_LOOKAHEAD equ (MAX_MATCH+MIN_MATCH+1) 109 110 111 112 MAX_MATCH equ 258 113 MIN_MATCH equ 3 114 MIN_LOOKAHEAD equ (MAX_MATCH + MIN_MATCH + 1) 115 MAX_MATCH_8_ equ ((MAX_MATCH + 7) AND 0FFF0h) 116 117 118 ;;; stack frame offsets 119 120 chainlenwmask equ esp + 0 ; high word: current chain len 121 ; low word: s->wmask 122 window equ esp + 4 ; local copy of s->window 123 windowbestlen equ esp + 8 ; s->window + bestlen 124 scanstart equ esp + 16 ; first two bytes of string 125 scanend equ esp + 12 ; last two bytes of string 126 scanalign equ esp + 20 ; dword-misalignment of string 127 nicematch equ esp + 24 ; a good enough match size 128 bestlen equ esp + 28 ; size of best match so far 129 scan equ esp + 32 ; ptr to string wanting match 130 131 LocalVarsSize equ 36 132 ; saved ebx byte esp + 36 133 ; saved edi byte esp + 40 134 ; saved esi byte esp + 44 135 ; saved ebp byte esp + 48 136 ; return address byte esp + 52 137 deflatestate equ esp + 56 ; the function arguments 138 curmatch equ esp + 60 139 140 ;;; Offsets for fields in the deflate_state structure. These numbers 141 ;;; are calculated from the definition of deflate_state, with the 142 ;;; assumption that the compiler will dword-align the fields. (Thus, 143 ;;; changing the definition of deflate_state could easily cause this 144 ;;; program to crash horribly, without so much as a warning at 145 ;;; compile time. Sigh.) 146 147 dsWSize equ 36+zlib1222add 148 dsWMask equ 44+zlib1222add 149 dsWindow equ 48+zlib1222add 150 dsPrev equ 56+zlib1222add 151 dsMatchLen equ 88+zlib1222add 152 dsPrevMatch equ 92+zlib1222add 153 dsStrStart equ 100+zlib1222add 154 dsMatchStart equ 104+zlib1222add 155 dsLookahead equ 108+zlib1222add 156 dsPrevLen equ 112+zlib1222add 157 dsMaxChainLen equ 116+zlib1222add 158 dsGoodMatch equ 132+zlib1222add 159 dsNiceMatch equ 136+zlib1222add 160 161 162 ;;; match686.asm -- Pentium-Pro-optimized version of longest_match() 163 ;;; Written for zlib 1.1.2 164 ;;; Copyright (C) 1998 Brian Raiter <breadbox (a] muppetlabs.com> 165 ;;; You can look at http://www.muppetlabs.com/~breadbox/software/assembly.html 166 ;;; 167 ;; 168 ;; This software is provided 'as-is', without any express or implied 169 ;; warranty. In no event will the authors be held liable for any damages 170 ;; arising from the use of this software. 171 ;; 172 ;; Permission is granted to anyone to use this software for any purpose, 173 ;; including commercial applications, and to alter it and redistribute it 174 ;; freely, subject to the following restrictions: 175 ;; 176 ;; 1. The origin of this software must not be misrepresented; you must not 177 ;; claim that you wrote the original software. If you use this software 178 ;; in a product, an acknowledgment in the product documentation would be 179 ;; appreciated but is not required. 180 ;; 2. Altered source versions must be plainly marked as such, and must not be 181 ;; misrepresented as being the original software 182 ;; 3. This notice may not be removed or altered from any source distribution. 183 ;; 184 185 ;GLOBAL _longest_match, _match_init 186 187 188 ;SECTION .text 189 190 ;;; uInt longest_match(deflate_state *deflatestate, IPos curmatch) 191 192 ;_longest_match: 193 IFDEF NOUNDERLINE 194 longest_match proc near 195 ELSE 196 _longest_match proc near 197 ENDIF 198 .FPO (9, 4, 0, 0, 1, 0) 199 200 ;;; Save registers that the compiler may be using, and adjust esp to 201 ;;; make room for our stack frame. 202 203 push ebp 204 push edi 205 push esi 206 push ebx 207 sub esp, LocalVarsSize 208 209 ;;; Retrieve the function arguments. ecx will hold cur_match 210 ;;; throughout the entire function. edx will hold the pointer to the 211 ;;; deflate_state structure during the function's setup (before 212 ;;; entering the main loop. 213 214 mov edx, [deflatestate] 215 mov ecx, [curmatch] 216 217 ;;; uInt wmask = s->w_mask; 218 ;;; unsigned chain_length = s->max_chain_length; 219 ;;; if (s->prev_length >= s->good_match) { 220 ;;; chain_length >>= 2; 221 ;;; } 222 223 mov eax, [edx + dsPrevLen] 224 mov ebx, [edx + dsGoodMatch] 225 cmp eax, ebx 226 mov eax, [edx + dsWMask] 227 mov ebx, [edx + dsMaxChainLen] 228 jl LastMatchGood 229 shr ebx, 2 230 LastMatchGood: 231 232 ;;; chainlen is decremented once beforehand so that the function can 233 ;;; use the sign flag instead of the zero flag for the exit test. 234 ;;; It is then shifted into the high word, to make room for the wmask 235 ;;; value, which it will always accompany. 236 237 dec ebx 238 shl ebx, 16 239 or ebx, eax 240 mov [chainlenwmask], ebx 241 242 ;;; if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; 243 244 mov eax, [edx + dsNiceMatch] 245 mov ebx, [edx + dsLookahead] 246 cmp ebx, eax 247 jl LookaheadLess 248 mov ebx, eax 249 LookaheadLess: mov [nicematch], ebx 250 251 ;;; register Bytef *scan = s->window + s->strstart; 252 253 mov esi, [edx + dsWindow] 254 mov [window], esi 255 mov ebp, [edx + dsStrStart] 256 lea edi, [esi + ebp] 257 mov [scan], edi 258 259 ;;; Determine how many bytes the scan ptr is off from being 260 ;;; dword-aligned. 261 262 mov eax, edi 263 neg eax 264 and eax, 3 265 mov [scanalign], eax 266 267 ;;; IPos limit = s->strstart > (IPos)MAX_DIST(s) ? 268 ;;; s->strstart - (IPos)MAX_DIST(s) : NIL; 269 270 mov eax, [edx + dsWSize] 271 sub eax, MIN_LOOKAHEAD 272 sub ebp, eax 273 jg LimitPositive 274 xor ebp, ebp 275 LimitPositive: 276 277 ;;; int best_len = s->prev_length; 278 279 mov eax, [edx + dsPrevLen] 280 mov [bestlen], eax 281 282 ;;; Store the sum of s->window + best_len in esi locally, and in esi. 283 284 add esi, eax 285 mov [windowbestlen], esi 286 287 ;;; register ush scan_start = *(ushf*)scan; 288 ;;; register ush scan_end = *(ushf*)(scan+best_len-1); 289 ;;; Posf *prev = s->prev; 290 291 movzx ebx, word ptr [edi] 292 mov [scanstart], ebx 293 movzx ebx, word ptr [edi + eax - 1] 294 mov [scanend], ebx 295 mov edi, [edx + dsPrev] 296 297 ;;; Jump into the main loop. 298 299 mov edx, [chainlenwmask] 300 jmp short LoopEntry 301 302 align 4 303 304 ;;; do { 305 ;;; match = s->window + cur_match; 306 ;;; if (*(ushf*)(match+best_len-1) != scan_end || 307 ;;; *(ushf*)match != scan_start) continue; 308 ;;; [...] 309 ;;; } while ((cur_match = prev[cur_match & wmask]) > limit 310 ;;; && --chain_length != 0); 311 ;;; 312 ;;; Here is the inner loop of the function. The function will spend the 313 ;;; majority of its time in this loop, and majority of that time will 314 ;;; be spent in the first ten instructions. 315 ;;; 316 ;;; Within this loop: 317 ;;; ebx = scanend 318 ;;; ecx = curmatch 319 ;;; edx = chainlenwmask - i.e., ((chainlen << 16) | wmask) 320 ;;; esi = windowbestlen - i.e., (window + bestlen) 321 ;;; edi = prev 322 ;;; ebp = limit 323 324 LookupLoop: 325 and ecx, edx 326 movzx ecx, word ptr [edi + ecx*2] 327 cmp ecx, ebp 328 jbe LeaveNow 329 sub edx, 00010000h 330 js LeaveNow 331 LoopEntry: movzx eax, word ptr [esi + ecx - 1] 332 cmp eax, ebx 333 jnz LookupLoop 334 mov eax, [window] 335 movzx eax, word ptr [eax + ecx] 336 cmp eax, [scanstart] 337 jnz LookupLoop 338 339 ;;; Store the current value of chainlen. 340 341 mov [chainlenwmask], edx 342 343 ;;; Point edi to the string under scrutiny, and esi to the string we 344 ;;; are hoping to match it up with. In actuality, esi and edi are 345 ;;; both pointed (MAX_MATCH_8 - scanalign) bytes ahead, and edx is 346 ;;; initialized to -(MAX_MATCH_8 - scanalign). 347 348 mov esi, [window] 349 mov edi, [scan] 350 add esi, ecx 351 mov eax, [scanalign] 352 mov edx, 0fffffef8h; -(MAX_MATCH_8) 353 lea edi, [edi + eax + 0108h] ;MAX_MATCH_8] 354 lea esi, [esi + eax + 0108h] ;MAX_MATCH_8] 355 356 ;;; Test the strings for equality, 8 bytes at a time. At the end, 357 ;;; adjust edx so that it is offset to the exact byte that mismatched. 358 ;;; 359 ;;; We already know at this point that the first three bytes of the 360 ;;; strings match each other, and they can be safely passed over before 361 ;;; starting the compare loop. So what this code does is skip over 0-3 362 ;;; bytes, as much as necessary in order to dword-align the edi 363 ;;; pointer. (esi will still be misaligned three times out of four.) 364 ;;; 365 ;;; It should be confessed that this loop usually does not represent 366 ;;; much of the total running time. Replacing it with a more 367 ;;; straightforward "rep cmpsb" would not drastically degrade 368 ;;; performance. 369 370 LoopCmps: 371 mov eax, [esi + edx] 372 xor eax, [edi + edx] 373 jnz LeaveLoopCmps 374 mov eax, [esi + edx + 4] 375 xor eax, [edi + edx + 4] 376 jnz LeaveLoopCmps4 377 add edx, 8 378 jnz LoopCmps 379 jmp short LenMaximum 380 LeaveLoopCmps4: add edx, 4 381 LeaveLoopCmps: test eax, 0000FFFFh 382 jnz LenLower 383 add edx, 2 384 shr eax, 16 385 LenLower: sub al, 1 386 adc edx, 0 387 388 ;;; Calculate the length of the match. If it is longer than MAX_MATCH, 389 ;;; then automatically accept it as the best possible match and leave. 390 391 lea eax, [edi + edx] 392 mov edi, [scan] 393 sub eax, edi 394 cmp eax, MAX_MATCH 395 jge LenMaximum 396 397 ;;; If the length of the match is not longer than the best match we 398 ;;; have so far, then forget it and return to the lookup loop. 399 400 mov edx, [deflatestate] 401 mov ebx, [bestlen] 402 cmp eax, ebx 403 jg LongerMatch 404 mov esi, [windowbestlen] 405 mov edi, [edx + dsPrev] 406 mov ebx, [scanend] 407 mov edx, [chainlenwmask] 408 jmp LookupLoop 409 410 ;;; s->match_start = cur_match; 411 ;;; best_len = len; 412 ;;; if (len >= nice_match) break; 413 ;;; scan_end = *(ushf*)(scan+best_len-1); 414 415 LongerMatch: mov ebx, [nicematch] 416 mov [bestlen], eax 417 mov [edx + dsMatchStart], ecx 418 cmp eax, ebx 419 jge LeaveNow 420 mov esi, [window] 421 add esi, eax 422 mov [windowbestlen], esi 423 movzx ebx, word ptr [edi + eax - 1] 424 mov edi, [edx + dsPrev] 425 mov [scanend], ebx 426 mov edx, [chainlenwmask] 427 jmp LookupLoop 428 429 ;;; Accept the current string, with the maximum possible length. 430 431 LenMaximum: mov edx, [deflatestate] 432 mov dword ptr [bestlen], MAX_MATCH 433 mov [edx + dsMatchStart], ecx 434 435 ;;; if ((uInt)best_len <= s->lookahead) return (uInt)best_len; 436 ;;; return s->lookahead; 437 438 LeaveNow: 439 mov edx, [deflatestate] 440 mov ebx, [bestlen] 441 mov eax, [edx + dsLookahead] 442 cmp ebx, eax 443 jg LookaheadRet 444 mov eax, ebx 445 LookaheadRet: 446 447 ;;; Restore the stack and return from whence we came. 448 449 add esp, LocalVarsSize 450 pop ebx 451 pop esi 452 pop edi 453 pop ebp 454 455 ret 456 ; please don't remove this string ! 457 ; Your can freely use match686 in any free or commercial app if you don't remove the string in the binary! 458 db 0dh,0ah,"asm686 with masm, optimised assembly code from Brian Raiter, written 1998",0dh,0ah 459 460 461 IFDEF NOUNDERLINE 462 longest_match endp 463 ELSE 464 _longest_match endp 465 ENDIF 466 467 IFDEF NOUNDERLINE 468 match_init proc near 469 ret 470 match_init endp 471 ELSE 472 _match_init proc near 473 ret 474 _match_init endp 475 ENDIF 476 477 478 _TEXT ends 479 end 480
