1 ;uInt longest_match_x64(
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3 ; IPos cur_match); /* current match */
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5 ; gvmat64.asm -- Asm portion of the optimized longest_match for 32 bits x86
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6 ; Copyright (C) 1995-2005 Jean-loup Gailly, Brian Raiter and Gilles Vollant.
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8 ; File written by Gilles Vollant, by converting to assembly the longest_match
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9 ; from Jean-loup Gailly in deflate.c of zLib and infoZip zip.
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11 ; and by taking inspiration on asm686 with masm, optimised assembly code
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12 ; from Brian Raiter, written 1998
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14 ; http://www.zlib.net
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15 ; http://www.winimage.com/zLibDll
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16 ; http://www.muppetlabs.com/~breadbox/software/assembly.html
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18 ; to compile this file for infozip Zip, I use option:
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19 ; ml64.exe /Flgvmat64 /c /Zi /DINFOZIP gvmat64.asm
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21 ; to compile this file for zLib, I use option:
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22 ; ml64.exe /Flgvmat64 /c /Zi gvmat64.asm
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23 ; Be carrefull to adapt zlib1222add below to your version of zLib
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24 ; (if you use a version of zLib before 1.0.4 or after 1.2.2.2, change
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25 ; value of zlib1222add later)
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27 ; This file compile with Microsoft Macro Assembler (x64) for AMD64
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29 ; ml64.exe is given with Visual Studio 2005 and Windows 2003 server DDK
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31 ; (you can get Windows 2003 server DDK with ml64 and cl for AMD64 from
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32 ; http://www.microsoft.com/whdc/devtools/ddk/default.mspx for low price)
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36 ;uInt longest_match(s, cur_match)
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38 ; IPos cur_match; /* current match */
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43 ;LocalVarsSize equ 88
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44 LocalVarsSize equ 72
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46 ; register used : rax,rbx,rcx,rdx,rsi,rdi,r8,r9,r10,r11,r12
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47 ; free register : r14,r15
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48 ; register can be saved : rsp
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50 chainlenwmask equ rsp + 8 - LocalVarsSize ; high word: current chain len
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51 ; low word: s->wmask
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52 ;window equ rsp + xx - LocalVarsSize ; local copy of s->window ; stored in r10
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53 ;windowbestlen equ rsp + xx - LocalVarsSize ; s->window + bestlen , use r10+r11
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54 ;scanstart equ rsp + xx - LocalVarsSize ; first two bytes of string ; stored in r12w
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55 ;scanend equ rsp + xx - LocalVarsSize ; last two bytes of string use ebx
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56 ;scanalign equ rsp + xx - LocalVarsSize ; dword-misalignment of string r13
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57 ;bestlen equ rsp + xx - LocalVarsSize ; size of best match so far -> r11d
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58 ;scan equ rsp + xx - LocalVarsSize ; ptr to string wanting match -> r9
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61 nicematch equ (rsp + 16 - LocalVarsSize) ; a good enough match size
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64 save_rdi equ rsp + 24 - LocalVarsSize
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65 save_rsi equ rsp + 32 - LocalVarsSize
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66 save_rbx equ rsp + 40 - LocalVarsSize
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67 save_rbp equ rsp + 48 - LocalVarsSize
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68 save_r12 equ rsp + 56 - LocalVarsSize
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69 save_r13 equ rsp + 64 - LocalVarsSize
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70 ;save_r14 equ rsp + 72 - LocalVarsSize
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71 ;save_r15 equ rsp + 80 - LocalVarsSize
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75 ; all the +4 offsets are due to the addition of pending_buf_size (in zlib
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76 ; in the deflate_state structure since the asm code was first written
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77 ; (if you compile with zlib 1.0.4 or older, remove the +4).
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78 ; Note : these value are good with a 8 bytes boundary pack structure
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83 MIN_LOOKAHEAD equ (MAX_MATCH+MIN_MATCH+1)
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86 ;;; Offsets for fields in the deflate_state structure. These numbers
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87 ;;; are calculated from the definition of deflate_state, with the
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88 ;;; assumption that the compiler will dword-align the fields. (Thus,
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89 ;;; changing the definition of deflate_state could easily cause this
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90 ;;; program to crash horribly, without so much as a warning at
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91 ;;; compile time. Sigh.)
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93 ; all the +zlib1222add offsets are due to the addition of fields
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94 ; in zlib in the deflate_state structure since the asm code was first written
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95 ; (if you compile with zlib 1.0.4 or older, use "zlib1222add equ (-4)").
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96 ; (if you compile with zlib between 1.0.5 and 1.2.2.1, use "zlib1222add equ 0").
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97 ; if you compile with zlib 1.2.2.2 or later , use "zlib1222add equ 8").
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103 COMM window_size:DWORD
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105 COMM window:BYTE:010040H
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106 COMM prev:WORD:08000H
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107 ; MatchLen : unused
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108 ; PrevMatch : unused
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109 COMM strstart:DWORD
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110 COMM match_start:DWORD
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111 ; Lookahead : ignore
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112 COMM prev_length:DWORD ; PrevLen
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113 COMM max_chain_length:DWORD
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114 COMM good_match:DWORD
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115 COMM nice_match:DWORD
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116 prev_ad equ OFFSET prev
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117 window_ad equ OFFSET window
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118 nicematch equ nice_match
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127 dsWSize equ 56+zlib1222add+(zlib1222add/2)
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128 dsWMask equ 64+zlib1222add+(zlib1222add/2)
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129 dsWindow equ 72+zlib1222add
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130 dsPrev equ 88+zlib1222add
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131 dsMatchLen equ 128+zlib1222add
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132 dsPrevMatch equ 132+zlib1222add
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133 dsStrStart equ 140+zlib1222add
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134 dsMatchStart equ 144+zlib1222add
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135 dsLookahead equ 148+zlib1222add
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136 dsPrevLen equ 152+zlib1222add
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137 dsMaxChainLen equ 156+zlib1222add
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138 dsGoodMatch equ 172+zlib1222add
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139 dsNiceMatch equ 176+zlib1222add
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141 window_size equ [ rcx + dsWSize]
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142 WMask equ [ rcx + dsWMask]
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143 window_ad equ [ rcx + dsWindow]
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144 prev_ad equ [ rcx + dsPrev]
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145 strstart equ [ rcx + dsStrStart]
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146 match_start equ [ rcx + dsMatchStart]
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147 Lookahead equ [ rcx + dsLookahead] ; 0ffffffffh on infozip
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148 prev_length equ [ rcx + dsPrevLen]
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149 max_chain_length equ [ rcx + dsMaxChainLen]
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150 good_match equ [ rcx + dsGoodMatch]
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151 nice_match equ [ rcx + dsNiceMatch]
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154 ; parameter 1 in r8(deflate state s), param 2 in rdx (cur match)
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156 ; see http://weblogs.asp.net/oldnewthing/archive/2004/01/14/58579.aspx and
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157 ; http://msdn.microsoft.com/library/en-us/kmarch/hh/kmarch/64bitAMD_8e951dd2-ee77-4728-8702-55ce4b5dd24a.xml.asp
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159 ; All registers must be preserved across the call, except for
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160 ; rax, rcx, rdx, r8, r9, r10, and r11, which are scratch.
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164 ;;; Save registers that the compiler may be using, and adjust esp to
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165 ;;; make room for our stack frame.
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168 ;;; Retrieve the function arguments. r8d will hold cur_match
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169 ;;; throughout the entire function. edx will hold the pointer to the
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170 ;;; deflate_state structure during the function's setup (before
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171 ;;; entering the main loop.
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173 ; parameter 1 in rcx (deflate_state* s), param 2 in edx -> r8 (cur match)
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175 ; this clear high 32 bits of r8, which can be garbage in both r8 and rdx
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188 ; mov [save_r14],r14
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189 ; mov [save_r15],r15
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192 ;;; uInt wmask = s->w_mask;
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193 ;;; unsigned chain_length = s->max_chain_length;
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194 ;;; if (s->prev_length >= s->good_match) {
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195 ;;; chain_length >>= 2;
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198 mov edi, prev_length
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199 mov esi, good_match
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201 mov ebx, max_chain_length
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207 ;;; chainlen is decremented once beforehand so that the function can
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208 ;;; use the sign flag instead of the zero flag for the exit test.
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209 ;;; It is then shifted into the high word, to make room for the wmask
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210 ;;; value, which it will always accompany.
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217 ;;; if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
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220 mov [chainlenwmask], ebx
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221 ; on infozip nice_match = [nice_match]
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223 mov eax, nice_match
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224 mov [chainlenwmask], ebx
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225 mov r10d, Lookahead
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228 mov [nicematch],r10d
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231 ;;; register Bytef *scan = s->window + s->strstart;
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234 lea r13, [r10 + rbp]
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236 ;;; Determine how many bytes the scan ptr is off from being
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243 ;;; IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
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244 ;;; s->strstart - (IPos)MAX_DIST(s) : NIL;
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246 mov eax,07efah ; MAX_DIST = (WSIZE-MIN_LOOKAHEAD) (0x8000-(3+8+1))
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248 mov eax, window_size
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249 sub eax, MIN_LOOKAHEAD
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254 mov r11d, prev_length
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258 ;;; int best_len = s->prev_length;
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261 ;;; Store the sum of s->window + best_len in esi locally, and in esi.
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265 ;;; register ush scan_start = *(ushf*)scan;
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266 ;;; register ush scan_end = *(ushf*)(scan+best_len-1);
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267 ;;; Posf *prev = s->prev;
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269 movzx r12d,word ptr [r9]
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270 movzx ebx, word ptr [r9 + r11 - 1]
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274 ;;; Jump into the main loop.
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276 mov edx, [chainlenwmask]
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278 cmp bx,word ptr [rsi + r8 - 1]
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279 jz LookupLoopIsZero
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284 movzx r8d, word ptr [rdi + r8*2]
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291 cmp bx,word ptr [rsi + r8 - 1]
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292 jz LookupLoopIsZero
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297 movzx r8d, word ptr [rdi + r8*2]
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304 cmp bx,word ptr [rsi + r8 - 1]
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305 jz LookupLoopIsZero
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310 movzx r8d, word ptr [rdi + r8*2]
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318 cmp bx,word ptr [rsi + r8 - 1]
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320 jmp LookupLoopIsZero
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324 ;;; match = s->window + cur_match;
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325 ;;; if (*(ushf*)(match+best_len-1) != scan_end ||
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326 ;;; *(ushf*)match != scan_start) continue;
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328 ;;; } while ((cur_match = prev[cur_match & wmask]) > limit
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329 ;;; && --chain_length != 0);
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331 ;;; Here is the inner loop of the function. The function will spend the
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332 ;;; majority of its time in this loop, and majority of that time will
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333 ;;; be spent in the first ten instructions.
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335 ;;; Within this loop:
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338 ;;; edx = chainlenwmask - i.e., ((chainlen << 16) | wmask)
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339 ;;; esi = windowbestlen - i.e., (window + bestlen)
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346 movzx r8d, word ptr [rdi + r8*2]
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354 cmp bx,word ptr [rsi + r8 - 1]
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357 cmp r12w, word ptr [r10 + r8]
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361 ;;; Store the current value of chainlen.
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362 mov [chainlenwmask], edx
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364 ;;; Point edi to the string under scrutiny, and esi to the string we
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365 ;;; are hoping to match it up with. In actuality, esi and edi are
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366 ;;; both pointed (MAX_MATCH_8 - scanalign) bytes ahead, and edx is
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367 ;;; initialized to -(MAX_MATCH_8 - scanalign).
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370 mov rdx, 0fffffffffffffef8h; -(MAX_MATCH_8)
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371 lea rsi, [rsi + r13 + 0108h] ;MAX_MATCH_8]
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372 lea rdi, [r9 + r13 + 0108h] ;MAX_MATCH_8]
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374 prefetcht1 [rsi+rdx]
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375 prefetcht1 [rdi+rdx]
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378 ;;; Test the strings for equality, 8 bytes at a time. At the end,
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379 ;;; adjust rdx so that it is offset to the exact byte that mismatched.
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381 ;;; We already know at this point that the first three bytes of the
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382 ;;; strings match each other, and they can be safely passed over before
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383 ;;; starting the compare loop. So what this code does is skip over 0-3
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384 ;;; bytes, as much as necessary in order to dword-align the edi
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385 ;;; pointer. (rsi will still be misaligned three times out of four.)
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387 ;;; It should be confessed that this loop usually does not represent
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388 ;;; much of the total running time. Replacing it with a more
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389 ;;; straightforward "rep cmpsb" would not drastically degrade
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394 mov rax, [rsi + rdx]
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395 xor rax, [rdi + rdx]
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398 mov rax, [rsi + rdx + 8]
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399 xor rax, [rdi + rdx + 8]
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403 mov rax, [rsi + rdx + 8+8]
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404 xor rax, [rdi + rdx + 8+8]
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405 jnz LeaveLoopCmps16
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410 LeaveLoopCmps16: add rdx,8
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411 LeaveLoopCmps8: add rdx,8
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414 test eax, 0000FFFFh
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417 test eax,0ffffffffh
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429 LenLower: sub al, 1
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431 ;;; Calculate the length of the match. If it is longer than MAX_MATCH,
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432 ;;; then automatically accept it as the best possible match and leave.
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434 lea rax, [rdi + rdx]
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439 ;;; If the length of the match is not longer than the best match we
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440 ;;; have so far, then forget it and return to the lookup loop.
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441 ;///////////////////////////////////
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449 mov edx, [chainlenwmask]
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452 ;;; s->match_start = cur_match;
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453 ;;; best_len = len;
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454 ;;; if (len >= nice_match) break;
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455 ;;; scan_end = *(ushf*)(scan+best_len-1);
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459 mov match_start, r8d
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460 cmp eax, [nicematch]
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465 movzx ebx, word ptr [r9 + rax - 1]
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467 mov edx, [chainlenwmask]
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470 ;;; Accept the current string, with the maximum possible length.
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474 mov match_start, r8d
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476 ;;; if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
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477 ;;; return s->lookahead;
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488 ;;; Restore the stack and return from whence we came.
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497 ; mov r14,[save_r14]
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498 ; mov r15,[save_r15]
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502 ; please don't remove this string !
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503 ; Your can freely use gvmat64 in any free or commercial app
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504 ; but it is far better don't remove the string in the binary!
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505 db 0dh,0ah,"asm686 with masm, optimised assembly code from Brian Raiter, written 1998, converted to amd 64 by Gilles Vollant 2005",0dh,0ah,0
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