554 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			NASM
		
	
	
	
	
	
		
		
			
		
	
	
			554 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			NASM
		
	
	
	
	
	
|   | ;uInt longest_match_x64( | ||
|  | ;    deflate_state *s, | ||
|  | ;    IPos cur_match);                             /* current match */ | ||
|  | 
 | ||
|  | ; gvmat64.asm -- Asm portion of the optimized longest_match for 32 bits x86_64 | ||
|  | ;  (AMD64 on Athlon 64, Opteron, Phenom | ||
|  | ;     and Intel EM64T on Pentium 4 with EM64T, Pentium D, Core 2 Duo, Core I5/I7) | ||
|  | ; Copyright (C) 1995-2010 Jean-loup Gailly, Brian Raiter and Gilles Vollant. | ||
|  | ; | ||
|  | ; File written by Gilles Vollant, by converting to assembly the longest_match | ||
|  | ;  from Jean-loup Gailly in deflate.c of zLib and infoZip zip. | ||
|  | ; | ||
|  | ;  and by taking inspiration on asm686 with masm, optimised assembly code | ||
|  | ;        from Brian Raiter, written 1998 | ||
|  | ; | ||
|  | ;  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. | ||
|  | ; | ||
|  | ; | ||
|  | ; | ||
|  | ;         http://www.zlib.net | ||
|  | ;         http://www.winimage.com/zLibDll | ||
|  | ;         http://www.muppetlabs.com/~breadbox/software/assembly.html | ||
|  | ; | ||
|  | ; to compile this file for infozip Zip, I use option: | ||
|  | ;   ml64.exe /Flgvmat64 /c /Zi /DINFOZIP gvmat64.asm | ||
|  | ; | ||
|  | ; to compile this file for zLib, I use option: | ||
|  | ;   ml64.exe /Flgvmat64 /c /Zi gvmat64.asm | ||
|  | ; Be carrefull to adapt zlib1222add below to your version of zLib | ||
|  | ;   (if you use a version of zLib before 1.0.4 or after 1.2.2.2, change | ||
|  | ;    value of zlib1222add later) | ||
|  | ; | ||
|  | ; This file compile with Microsoft Macro Assembler (x64) for AMD64 | ||
|  | ; | ||
|  | ;   ml64.exe is given with Visual Studio 2005/2008/2010 and Windows WDK | ||
|  | ; | ||
|  | ;   (you can get Windows WDK with ml64 for AMD64 from | ||
|  | ;      http://www.microsoft.com/whdc/Devtools/wdk/default.mspx for low price) | ||
|  | ; | ||
|  | 
 | ||
|  | 
 | ||
|  | ;uInt longest_match(s, cur_match) | ||
|  | ;    deflate_state *s; | ||
|  | ;    IPos cur_match;                             /* current match */ | ||
|  | .code | ||
|  | longest_match PROC | ||
|  | 
 | ||
|  | 
 | ||
|  | ;LocalVarsSize   equ 88 | ||
|  |  LocalVarsSize   equ 72 | ||
|  | 
 | ||
|  | ; register used : rax,rbx,rcx,rdx,rsi,rdi,r8,r9,r10,r11,r12 | ||
|  | ; free register :  r14,r15 | ||
|  | ; register can be saved : rsp | ||
|  | 
 | ||
|  |  chainlenwmask   equ  rsp + 8 - LocalVarsSize    ; high word: current chain len | ||
|  |                                                  ; low word: s->wmask | ||
|  | ;window          equ  rsp + xx - LocalVarsSize   ; local copy of s->window ; stored in r10 | ||
|  | ;windowbestlen   equ  rsp + xx - LocalVarsSize   ; s->window + bestlen , use r10+r11 | ||
|  | ;scanstart       equ  rsp + xx - LocalVarsSize   ; first two bytes of string ; stored in r12w | ||
|  | ;scanend         equ  rsp + xx - LocalVarsSize   ; last two bytes of string use ebx | ||
|  | ;scanalign       equ  rsp + xx - LocalVarsSize   ; dword-misalignment of string r13 | ||
|  | ;bestlen         equ  rsp + xx - LocalVarsSize   ; size of best match so far -> r11d | ||
|  | ;scan            equ  rsp + xx - LocalVarsSize   ; ptr to string wanting match -> r9 | ||
|  | IFDEF INFOZIP | ||
|  | ELSE | ||
|  |  nicematch       equ  (rsp + 16 - LocalVarsSize) ; a good enough match size | ||
|  | ENDIF | ||
|  | 
 | ||
|  | save_rdi        equ  rsp + 24 - LocalVarsSize | ||
|  | save_rsi        equ  rsp + 32 - LocalVarsSize | ||
|  | save_rbx        equ  rsp + 40 - LocalVarsSize | ||
|  | save_rbp        equ  rsp + 48 - LocalVarsSize | ||
|  | save_r12        equ  rsp + 56 - LocalVarsSize | ||
|  | save_r13        equ  rsp + 64 - LocalVarsSize | ||
|  | ;save_r14        equ  rsp + 72 - LocalVarsSize | ||
|  | ;save_r15        equ  rsp + 80 - LocalVarsSize | ||
|  | 
 | ||
|  | 
 | ||
|  | ; summary of register usage | ||
|  | ; scanend     ebx | ||
|  | ; scanendw    bx | ||
|  | ; chainlenwmask   edx | ||
|  | ; curmatch    rsi | ||
|  | ; curmatchd   esi | ||
|  | ; windowbestlen   r8 | ||
|  | ; scanalign   r9 | ||
|  | ; scanalignd  r9d | ||
|  | ; window      r10 | ||
|  | ; bestlen     r11 | ||
|  | ; bestlend    r11d | ||
|  | ; scanstart   r12d | ||
|  | ; scanstartw  r12w | ||
|  | ; scan        r13 | ||
|  | ; nicematch   r14d | ||
|  | ; limit       r15 | ||
|  | ; limitd      r15d | ||
|  | ; prev        rcx | ||
|  | 
 | ||
|  | ;  all the +4 offsets are due to the addition of pending_buf_size (in zlib | ||
|  | ;  in the deflate_state structure since the asm code was first written | ||
|  | ;  (if you compile with zlib 1.0.4 or older, remove the +4). | ||
|  | ;  Note : these value are good with a 8 bytes boundary pack structure | ||
|  | 
 | ||
|  | 
 | ||
|  |     MAX_MATCH           equ     258 | ||
|  |     MIN_MATCH           equ     3 | ||
|  |     MIN_LOOKAHEAD       equ     (MAX_MATCH+MIN_MATCH+1) | ||
|  | 
 | ||
|  | 
 | ||
|  | ;;; 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.) | ||
|  | 
 | ||
|  | ;  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"). | ||
|  | 
 | ||
|  | 
 | ||
|  | IFDEF INFOZIP | ||
|  | 
 | ||
|  | _DATA   SEGMENT | ||
|  | COMM    window_size:DWORD | ||
|  | ; WMask ; 7fff | ||
|  | COMM    window:BYTE:010040H | ||
|  | COMM    prev:WORD:08000H | ||
|  | ; MatchLen : unused | ||
|  | ; PrevMatch : unused | ||
|  | COMM    strstart:DWORD | ||
|  | COMM    match_start:DWORD | ||
|  | ; Lookahead : ignore | ||
|  | COMM    prev_length:DWORD ; PrevLen | ||
|  | COMM    max_chain_length:DWORD | ||
|  | COMM    good_match:DWORD | ||
|  | COMM    nice_match:DWORD | ||
|  | prev_ad equ OFFSET prev | ||
|  | window_ad equ OFFSET window | ||
|  | nicematch equ nice_match | ||
|  | _DATA ENDS | ||
|  | WMask equ 07fffh | ||
|  | 
 | ||
|  | ELSE | ||
|  | 
 | ||
|  |   IFNDEF zlib1222add | ||
|  |     zlib1222add equ 8 | ||
|  |   ENDIF | ||
|  | dsWSize         equ 56+zlib1222add+(zlib1222add/2) | ||
|  | dsWMask         equ 64+zlib1222add+(zlib1222add/2) | ||
|  | dsWindow        equ 72+zlib1222add | ||
|  | dsPrev          equ 88+zlib1222add | ||
|  | dsMatchLen      equ 128+zlib1222add | ||
|  | dsPrevMatch     equ 132+zlib1222add | ||
|  | dsStrStart      equ 140+zlib1222add | ||
|  | dsMatchStart    equ 144+zlib1222add | ||
|  | dsLookahead     equ 148+zlib1222add | ||
|  | dsPrevLen       equ 152+zlib1222add | ||
|  | dsMaxChainLen   equ 156+zlib1222add | ||
|  | dsGoodMatch     equ 172+zlib1222add | ||
|  | dsNiceMatch     equ 176+zlib1222add | ||
|  | 
 | ||
|  | window_size     equ [ rcx + dsWSize] | ||
|  | WMask           equ [ rcx + dsWMask] | ||
|  | window_ad       equ [ rcx + dsWindow] | ||
|  | prev_ad         equ [ rcx + dsPrev] | ||
|  | strstart        equ [ rcx + dsStrStart] | ||
|  | match_start     equ [ rcx + dsMatchStart] | ||
|  | Lookahead       equ [ rcx + dsLookahead] ; 0ffffffffh on infozip | ||
|  | prev_length     equ [ rcx + dsPrevLen] | ||
|  | max_chain_length equ [ rcx + dsMaxChainLen] | ||
|  | good_match      equ [ rcx + dsGoodMatch] | ||
|  | nice_match      equ [ rcx + dsNiceMatch] | ||
|  | ENDIF | ||
|  | 
 | ||
|  | ; parameter 1 in r8(deflate state s), param 2 in rdx (cur match) | ||
|  | 
 | ||
|  | ; see http://weblogs.asp.net/oldnewthing/archive/2004/01/14/58579.aspx and | ||
|  | ; http://msdn.microsoft.com/library/en-us/kmarch/hh/kmarch/64bitAMD_8e951dd2-ee77-4728-8702-55ce4b5dd24a.xml.asp | ||
|  | ; | ||
|  | ; All registers must be preserved across the call, except for | ||
|  | ;   rax, rcx, rdx, r8, r9, r10, and r11, which are scratch. | ||
|  | 
 | ||
|  | 
 | ||
|  | 
 | ||
|  | ;;; Save registers that the compiler may be using, and adjust esp to | ||
|  | ;;; make room for our stack frame. | ||
|  | 
 | ||
|  | 
 | ||
|  | ;;; Retrieve the function arguments. r8d 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. | ||
|  | 
 | ||
|  | ; parameter 1 in rcx (deflate_state* s), param 2 in edx -> r8 (cur match) | ||
|  | 
 | ||
|  | ; this clear high 32 bits of r8, which can be garbage in both r8 and rdx | ||
|  | 
 | ||
|  |         mov [save_rdi],rdi | ||
|  |         mov [save_rsi],rsi | ||
|  |         mov [save_rbx],rbx | ||
|  |         mov [save_rbp],rbp | ||
|  | IFDEF INFOZIP | ||
|  |         mov r8d,ecx | ||
|  | ELSE | ||
|  |         mov r8d,edx | ||
|  | ENDIF | ||
|  |         mov [save_r12],r12 | ||
|  |         mov [save_r13],r13 | ||
|  | ;        mov [save_r14],r14 | ||
|  | ;        mov [save_r15],r15 | ||
|  | 
 | ||
|  | 
 | ||
|  | ;;; uInt wmask = s->w_mask; | ||
|  | ;;; unsigned chain_length = s->max_chain_length; | ||
|  | ;;; if (s->prev_length >= s->good_match) { | ||
|  | ;;;     chain_length >>= 2; | ||
|  | ;;; } | ||
|  | 
 | ||
|  |         mov edi, prev_length | ||
|  |         mov esi, good_match | ||
|  |         mov eax, WMask | ||
|  |         mov ebx, max_chain_length | ||
|  |         cmp edi, esi | ||
|  |         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 | ||
|  | 
 | ||
|  | ;;; on zlib only | ||
|  | ;;; if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; | ||
|  | 
 | ||
|  | IFDEF INFOZIP | ||
|  |         mov [chainlenwmask], ebx | ||
|  | ; on infozip nice_match = [nice_match] | ||
|  | ELSE | ||
|  |         mov eax, nice_match | ||
|  |         mov [chainlenwmask], ebx | ||
|  |         mov r10d, Lookahead | ||
|  |         cmp r10d, eax | ||
|  |         cmovnl r10d, eax | ||
|  |         mov [nicematch],r10d | ||
|  | ENDIF | ||
|  | 
 | ||
|  | ;;; register Bytef *scan = s->window + s->strstart; | ||
|  |         mov r10, window_ad | ||
|  |         mov ebp, strstart | ||
|  |         lea r13, [r10 + rbp] | ||
|  | 
 | ||
|  | ;;; Determine how many bytes the scan ptr is off from being | ||
|  | ;;; dword-aligned. | ||
|  | 
 | ||
|  |          mov r9,r13 | ||
|  |          neg r13 | ||
|  |          and r13,3 | ||
|  | 
 | ||
|  | ;;; IPos limit = s->strstart > (IPos)MAX_DIST(s) ? | ||
|  | ;;;     s->strstart - (IPos)MAX_DIST(s) : NIL; | ||
|  | IFDEF INFOZIP | ||
|  |         mov eax,07efah ; MAX_DIST = (WSIZE-MIN_LOOKAHEAD) (0x8000-(3+8+1)) | ||
|  | ELSE | ||
|  |         mov eax, window_size | ||
|  |         sub eax, MIN_LOOKAHEAD | ||
|  | ENDIF | ||
|  |         xor edi,edi | ||
|  |         sub ebp, eax | ||
|  | 
 | ||
|  |         mov r11d, prev_length | ||
|  | 
 | ||
|  |         cmovng ebp,edi | ||
|  | 
 | ||
|  | ;;; int best_len = s->prev_length; | ||
|  | 
 | ||
|  | 
 | ||
|  | ;;; Store the sum of s->window + best_len in esi locally, and in esi. | ||
|  | 
 | ||
|  |        lea  rsi,[r10+r11] | ||
|  | 
 | ||
|  | ;;; register ush scan_start = *(ushf*)scan; | ||
|  | ;;; register ush scan_end   = *(ushf*)(scan+best_len-1); | ||
|  | ;;; Posf *prev = s->prev; | ||
|  | 
 | ||
|  |         movzx r12d,word ptr [r9] | ||
|  |         movzx ebx, word ptr [r9 + r11 - 1] | ||
|  | 
 | ||
|  |         mov rdi, prev_ad | ||
|  | 
 | ||
|  | ;;; Jump into the main loop. | ||
|  | 
 | ||
|  |         mov edx, [chainlenwmask] | ||
|  | 
 | ||
|  |         cmp bx,word ptr [rsi + r8 - 1] | ||
|  |         jz  LookupLoopIsZero | ||
|  | 
 | ||
|  | LookupLoop1: | ||
|  |         and r8d, edx | ||
|  | 
 | ||
|  |         movzx   r8d, word ptr [rdi + r8*2] | ||
|  |         cmp r8d, ebp | ||
|  |         jbe LeaveNow | ||
|  |         sub edx, 00010000h | ||
|  |         js  LeaveNow | ||
|  | 
 | ||
|  | LoopEntry1: | ||
|  |         cmp bx,word ptr [rsi + r8 - 1] | ||
|  |         jz  LookupLoopIsZero | ||
|  | 
 | ||
|  | LookupLoop2: | ||
|  |         and r8d, edx | ||
|  | 
 | ||
|  |         movzx   r8d, word ptr [rdi + r8*2] | ||
|  |         cmp r8d, ebp | ||
|  |         jbe LeaveNow | ||
|  |         sub edx, 00010000h | ||
|  |         js  LeaveNow | ||
|  | 
 | ||
|  | LoopEntry2: | ||
|  |         cmp bx,word ptr [rsi + r8 - 1] | ||
|  |         jz  LookupLoopIsZero | ||
|  | 
 | ||
|  | LookupLoop4: | ||
|  |         and r8d, edx | ||
|  | 
 | ||
|  |         movzx   r8d, word ptr [rdi + r8*2] | ||
|  |         cmp r8d, ebp | ||
|  |         jbe LeaveNow | ||
|  |         sub edx, 00010000h | ||
|  |         js  LeaveNow | ||
|  | 
 | ||
|  | LoopEntry4: | ||
|  | 
 | ||
|  |         cmp bx,word ptr [rsi + r8 - 1] | ||
|  |         jnz LookupLoop1 | ||
|  |         jmp LookupLoopIsZero | ||
|  | 
 | ||
|  | 
 | ||
|  | ;;; 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 | ||
|  | ;;; r8d = curmatch | ||
|  | ;;; edx = chainlenwmask - i.e., ((chainlen << 16) | wmask) | ||
|  | ;;; esi = windowbestlen - i.e., (window + bestlen) | ||
|  | ;;; edi = prev | ||
|  | ;;; ebp = limit | ||
|  | 
 | ||
|  | LookupLoop: | ||
|  |         and r8d, edx | ||
|  | 
 | ||
|  |         movzx   r8d, word ptr [rdi + r8*2] | ||
|  |         cmp r8d, ebp | ||
|  |         jbe LeaveNow | ||
|  |         sub edx, 00010000h | ||
|  |         js  LeaveNow | ||
|  | 
 | ||
|  | LoopEntry: | ||
|  | 
 | ||
|  |         cmp bx,word ptr [rsi + r8 - 1] | ||
|  |         jnz LookupLoop1 | ||
|  | LookupLoopIsZero: | ||
|  |         cmp     r12w, word ptr [r10 + r8] | ||
|  |         jnz LookupLoop1 | ||
|  | 
 | ||
|  | 
 | ||
|  | ;;; 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). | ||
|  | 
 | ||
|  |         lea rsi,[r8+r10] | ||
|  |         mov rdx, 0fffffffffffffef8h; -(MAX_MATCH_8) | ||
|  |         lea rsi, [rsi + r13 + 0108h] ;MAX_MATCH_8] | ||
|  |         lea rdi, [r9 + r13 + 0108h] ;MAX_MATCH_8] | ||
|  | 
 | ||
|  |         prefetcht1 [rsi+rdx] | ||
|  |         prefetcht1 [rdi+rdx] | ||
|  | 
 | ||
|  | 
 | ||
|  | ;;; Test the strings for equality, 8 bytes at a time. At the end, | ||
|  | ;;; adjust rdx 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. (rsi 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 rax, [rsi + rdx] | ||
|  |         xor rax, [rdi + rdx] | ||
|  |         jnz LeaveLoopCmps | ||
|  | 
 | ||
|  |         mov rax, [rsi + rdx + 8] | ||
|  |         xor rax, [rdi + rdx + 8] | ||
|  |         jnz LeaveLoopCmps8 | ||
|  | 
 | ||
|  | 
 | ||
|  |         mov rax, [rsi + rdx + 8+8] | ||
|  |         xor rax, [rdi + rdx + 8+8] | ||
|  |         jnz LeaveLoopCmps16 | ||
|  | 
 | ||
|  |         add rdx,8+8+8 | ||
|  | 
 | ||
|  |         jnz short LoopCmps | ||
|  |         jmp short LenMaximum | ||
|  | LeaveLoopCmps16: add rdx,8 | ||
|  | LeaveLoopCmps8: add rdx,8 | ||
|  | LeaveLoopCmps: | ||
|  | 
 | ||
|  |         test    eax, 0000FFFFh | ||
|  |         jnz LenLower | ||
|  | 
 | ||
|  |         test eax,0ffffffffh | ||
|  | 
 | ||
|  |         jnz LenLower32 | ||
|  | 
 | ||
|  |         add rdx,4 | ||
|  |         shr rax,32 | ||
|  |         or ax,ax | ||
|  |         jnz LenLower | ||
|  | 
 | ||
|  | LenLower32: | ||
|  |         shr eax,16 | ||
|  |         add rdx,2 | ||
|  | LenLower:   sub al, 1 | ||
|  |         adc rdx, 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 rax, [rdi + rdx] | ||
|  |         sub rax, r9 | ||
|  |         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. | ||
|  | ;/////////////////////////////////// | ||
|  | 
 | ||
|  |         cmp eax, r11d | ||
|  |         jg  LongerMatch | ||
|  | 
 | ||
|  |         lea rsi,[r10+r11] | ||
|  | 
 | ||
|  |         mov rdi, prev_ad | ||
|  |         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 r11d, eax | ||
|  |         mov match_start, r8d | ||
|  |         cmp eax, [nicematch] | ||
|  |         jge LeaveNow | ||
|  | 
 | ||
|  |         lea rsi,[r10+rax] | ||
|  | 
 | ||
|  |         movzx   ebx, word ptr [r9 + rax - 1] | ||
|  |         mov rdi, prev_ad | ||
|  |         mov edx, [chainlenwmask] | ||
|  |         jmp LookupLoop | ||
|  | 
 | ||
|  | ;;; Accept the current string, with the maximum possible length. | ||
|  | 
 | ||
|  | LenMaximum: | ||
|  |         mov r11d,MAX_MATCH | ||
|  |         mov match_start, r8d | ||
|  | 
 | ||
|  | ;;; if ((uInt)best_len <= s->lookahead) return (uInt)best_len; | ||
|  | ;;; return s->lookahead; | ||
|  | 
 | ||
|  | LeaveNow: | ||
|  | IFDEF INFOZIP | ||
|  |         mov eax,r11d | ||
|  | ELSE | ||
|  |         mov eax, Lookahead | ||
|  |         cmp r11d, eax | ||
|  |         cmovng eax, r11d | ||
|  | ENDIF | ||
|  | 
 | ||
|  | ;;; Restore the stack and return from whence we came. | ||
|  | 
 | ||
|  | 
 | ||
|  |         mov rsi,[save_rsi] | ||
|  |         mov rdi,[save_rdi] | ||
|  |         mov rbx,[save_rbx] | ||
|  |         mov rbp,[save_rbp] | ||
|  |         mov r12,[save_r12] | ||
|  |         mov r13,[save_r13] | ||
|  | ;        mov r14,[save_r14] | ||
|  | ;        mov r15,[save_r15] | ||
|  | 
 | ||
|  | 
 | ||
|  |         ret 0 | ||
|  | ; please don't remove this string ! | ||
|  | ; Your can freely use gvmat64 in any free or commercial app | ||
|  | ; but it is far better don't remove the string in the binary! | ||
|  |     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 | ||
|  | longest_match   ENDP | ||
|  | 
 | ||
|  | match_init PROC | ||
|  |   ret 0 | ||
|  | match_init ENDP | ||
|  | 
 | ||
|  | 
 | ||
|  | END |