/*

;uInt longest_match_x64(

;    deflate_state *s,

;    IPos cur_match);                             // current match 

; gvmat64.S -- 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)

; this file is translation from gvmat64.asm to GCC 4.x (for Linux, Mac XCode)

; 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 zLib, I use option:

;   gcc -c -arch x86_64 gvmat64.S

;uInt longest_match(s, cur_match)

;    deflate_state *s;

;    IPos cur_match;                             // current match /

;

; with XCode for Mac, I had strange error with some jump on intel syntax

; this is why BEFORE_JMP and AFTER_JMP are used

 */

#define BEFORE_JMP .att_syntax

#define AFTER_JMP .intel_syntax noprefix

#ifndef NO_UNDERLINE

#	define	match_init	_match_init

#	define	longest_match	_longest_match

#endif

.intel_syntax noprefix

.globl	match_init, longest_match

.text

longest_match:

#define LocalVarsSize 96

/*

; register used : rax,rbx,rcx,rdx,rsi,rdi,r8,r9,r10,r11,r12

; free register :  r14,r15

; register can be saved : rsp

*/

#define chainlenwmask     (rsp + 8 - LocalVarsSize)

#define nicematch         (rsp + 16 - LocalVarsSize)

#define save_rdi        (rsp + 24 - LocalVarsSize)

#define save_rsi        (rsp + 32 - LocalVarsSize)

#define save_rbx        (rsp + 40 - LocalVarsSize)

#define save_rbp        (rsp + 48 - LocalVarsSize)

#define save_r12        (rsp + 56 - LocalVarsSize)

#define save_r13        (rsp + 64 - LocalVarsSize)

#define save_r14        (rsp + 72 - LocalVarsSize)

#define save_r15        (rsp + 80 - LocalVarsSize)

/*

;  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

*/

#define    MAX_MATCH              258

#define    MIN_MATCH              3

#define    MIN_LOOKAHEAD          (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").

*/

/* you can check the structure offset by running

#include <stdlib.h></stdlib.h>

#include <stdio.h></stdio.h>

#include "deflate.h"

void print_depl()

{

deflate_state ds;

deflate_state *s=&ds;

printf("size pointer=%u\n",(int)sizeof(void*));

printf("#define dsWSize         %u\n",(int)(((char*)&(s->w_size))-((char*)s)));

printf("#define dsWMask         %u\n",(int)(((char*)&(s->w_mask))-((char*)s)));

printf("#define dsWindow        %u\n",(int)(((char*)&(s->window))-((char*)s)));

printf("#define dsPrev          %u\n",(int)(((char*)&(s->prev))-((char*)s)));

printf("#define dsMatchLen      %u\n",(int)(((char*)&(s->match_length))-((char*)s)));

printf("#define dsPrevMatch     %u\n",(int)(((char*)&(s->prev_match))-((char*)s)));

printf("#define dsStrStart      %u\n",(int)(((char*)&(s->strstart))-((char*)s)));

printf("#define dsMatchStart    %u\n",(int)(((char*)&(s->match_start))-((char*)s)));

printf("#define dsLookahead     %u\n",(int)(((char*)&(s->lookahead))-((char*)s)));

printf("#define dsPrevLen       %u\n",(int)(((char*)&(s->prev_length))-((char*)s)));

printf("#define dsMaxChainLen   %u\n",(int)(((char*)&(s->max_chain_length))-((char*)s)));

printf("#define dsGoodMatch     %u\n",(int)(((char*)&(s->good_match))-((char*)s)));

printf("#define dsNiceMatch     %u\n",(int)(((char*)&(s->nice_match))-((char*)s)));

}

*/

#define dsWSize          68

#define dsWMask          76

#define dsWindow         80

#define dsPrev           96

#define dsMatchLen       144

#define dsPrevMatch      148

#define dsStrStart       156

#define dsMatchStart     160

#define dsLookahead      164

#define dsPrevLen        168

#define dsMaxChainLen    172

#define dsGoodMatch      188

#define dsNiceMatch      192

#define window_size      [ rcx + dsWSize]

#define WMask            [ rcx + dsWMask]

#define window_ad        [ rcx + dsWindow]

#define prev_ad          [ rcx + dsPrev]

#define strstart         [ rcx + dsStrStart]

#define match_start      [ rcx + dsMatchStart]

#define Lookahead        [ rcx + dsLookahead] //; 0ffffffffh on infozip

#define prev_length      [ rcx + dsPrevLen]

#define max_chain_length [ rcx + dsMaxChainLen]

#define good_match       [ rcx + dsGoodMatch]

#define nice_match       [ rcx + dsNiceMatch]

/*

; windows:

; parameter 1 in rcx(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.

;

; gcc on macosx-linux:

; see http://www.x86-64.org/documentation/abi-0.99.pdf

; param 1 in rdi, param 2 in rsi

; rbx, rsp, rbp, r12 to r15 must be preserved

;;; 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.

; ms: parameter 1 in rcx (deflate_state* s), param 2 in edx -> r8 (cur match)

; mac: param 1 in rdi, param 2 rsi

; this clear high 32 bits of r8, which can be garbage in both r8 and rdx

*/

        mov [save_rbx],rbx

        mov [save_rbp],rbp

        mov rcx,rdi

        mov r8d,esi

        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;

        mov eax, nice_match

        mov [chainlenwmask], ebx

        mov r10d, Lookahead

        cmp r10d, eax

        cmovnl r10d, eax

        mov [nicematch],r10d

//;;; 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;

        mov eax, window_size

        sub eax, MIN_LOOKAHEAD

        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, 0x00010000

		BEFORE_JMP

        js  LeaveNow

		AFTER_JMP

LoopEntry1:

        cmp bx,word ptr [rsi + r8 - 1]

		BEFORE_JMP

        jz  LookupLoopIsZero

		AFTER_JMP

LookupLoop2:

        and r8d, edx

        movzx   r8d, word ptr [rdi + r8*2]

        cmp r8d, ebp

		BEFORE_JMP

        jbe LeaveNow

		AFTER_JMP

        sub edx, 0x00010000

		BEFORE_JMP

        js  LeaveNow

		AFTER_JMP

LoopEntry2:

        cmp bx,word ptr [rsi + r8 - 1]

		BEFORE_JMP

        jz  LookupLoopIsZero

		AFTER_JMP

LookupLoop4:

        and r8d, edx

        movzx   r8d, word ptr [rdi + r8*2]

        cmp r8d, ebp

		BEFORE_JMP

        jbe LeaveNow

		AFTER_JMP

        sub edx, 0x00010000

		BEFORE_JMP

        js  LeaveNow

		AFTER_JMP

LoopEntry4:

        cmp bx,word ptr [rsi + r8 - 1]

		BEFORE_JMP

        jnz LookupLoop1

        jmp LookupLoopIsZero

		AFTER_JMP

/*

;;; 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

*/

.balign 16

LookupLoop:

        and r8d, edx

        movzx   r8d, word ptr [rdi + r8*2]

        cmp r8d, ebp

		BEFORE_JMP

        jbe LeaveNow

		AFTER_JMP

        sub edx, 0x00010000

		BEFORE_JMP

        js  LeaveNow

		AFTER_JMP

LoopEntry:

        cmp bx,word ptr [rsi + r8 - 1]

		BEFORE_JMP

        jnz LookupLoop1

		AFTER_JMP

LookupLoopIsZero:

        cmp     r12w, word ptr [r10 + r8]

		BEFORE_JMP

        jnz LookupLoop1

		AFTER_JMP

//;;; 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, 0xfffffffffffffef8 //; -(MAX_MATCH_8)

        lea rsi, [rsi + r13 + 0x0108] //;MAX_MATCH_8]

        lea rdi, [r9 + r13 + 0x0108] //;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

		BEFORE_JMP

        jnz  LoopCmps

        jmp  LenMaximum

		AFTER_JMP

LeaveLoopCmps16: add rdx,8

LeaveLoopCmps8: add rdx,8

LeaveLoopCmps:

        test    eax, 0x0000FFFF

        jnz LenLower

        test eax,0xffffffff

        jnz LenLower32

        add rdx,4

        shr rax,32

        or ax,ax

		BEFORE_JMP

        jnz LenLower

		AFTER_JMP

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

		BEFORE_JMP

        jge LenMaximum

		AFTER_JMP

/*

;;; 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]

		BEFORE_JMP

        jmp LookupLoop

		AFTER_JMP

/*

;;;         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]

		BEFORE_JMP

        jge LeaveNow

		AFTER_JMP

        lea rsi,[r10+rax]

        movzx   ebx, word ptr [r9 + rax - 1]

        mov rdi, prev_ad

        mov edx, [chainlenwmask]

		BEFORE_JMP

        jmp LookupLoop

		AFTER_JMP

//;;; 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:

        mov eax, Lookahead

        cmp r11d, eax

        cmovng eax, r11d

//;;; 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

match_init:

  ret 0