+++ /dev/null
-/*
- * match.S -- optimized version of longest_match()
- * based on the similar work by Gilles Vollant, and Brian Raiter, written 1998
- *
- * This is free software; you can redistribute it and/or modify it
- * under the terms of the BSD License. Use by owners of Che Guevarra
- * parafernalia is prohibited, where possible, and highly discouraged
- * elsewhere.
- */
-
-#ifndef NO_UNDERLINE
-# define match_init _match_init
-# define longest_match _longest_match
-#endif
-
-#define scanend ebx
-#define scanendw bx
-#define chainlenwmask edx /* high word: current chain len low word: s->wmask */
-#define curmatch rsi
-#define curmatchd esi
-#define windowbestlen r8
-#define scanalign r9
-#define scanalignd r9d
-#define window r10
-#define bestlen r11
-#define bestlend r11d
-#define scanstart r12d
-#define scanstartw r12w
-#define scan r13
-#define nicematch r14d
-#define limit r15
-#define limitd r15d
-#define prev rcx
-
-/*
- * The 258 is a "magic number, not a parameter -- changing it
- * breaks the hell loose
- */
-#define MAX_MATCH (258)
-#define MIN_MATCH (3)
-#define MIN_LOOKAHEAD (MAX_MATCH + MIN_MATCH + 1)
-#define MAX_MATCH_8 ((MAX_MATCH + 7) & ~7)
-
-/* stack frame offsets */
-#define LocalVarsSize (112)
-#define _chainlenwmask ( 8-LocalVarsSize)(%rsp)
-#define _windowbestlen (16-LocalVarsSize)(%rsp)
-#define save_r14 (24-LocalVarsSize)(%rsp)
-#define save_rsi (32-LocalVarsSize)(%rsp)
-#define save_rbx (40-LocalVarsSize)(%rsp)
-#define save_r12 (56-LocalVarsSize)(%rsp)
-#define save_r13 (64-LocalVarsSize)(%rsp)
-#define save_r15 (80-LocalVarsSize)(%rsp)
-
-
-.globl match_init, longest_match
-
-/*
- * On AMD64 the first argument of a function (in our case -- the pointer to
- * deflate_state structure) is passed in %rdi, hence our offsets below are
- * all off of that.
- */
-
-/* you can check the structure offset by running
-
-#include <stdlib.h>
-#include <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 (%3u)(%%rdi)\n",(int)(((char*)&(s->w_size))-((char*)s)));
-printf("#define dsWMask (%3u)(%%rdi)\n",(int)(((char*)&(s->w_mask))-((char*)s)));
-printf("#define dsWindow (%3u)(%%rdi)\n",(int)(((char*)&(s->window))-((char*)s)));
-printf("#define dsPrev (%3u)(%%rdi)\n",(int)(((char*)&(s->prev))-((char*)s)));
-printf("#define dsMatchLen (%3u)(%%rdi)\n",(int)(((char*)&(s->match_length))-((char*)s)));
-printf("#define dsPrevMatch (%3u)(%%rdi)\n",(int)(((char*)&(s->prev_match))-((char*)s)));
-printf("#define dsStrStart (%3u)(%%rdi)\n",(int)(((char*)&(s->strstart))-((char*)s)));
-printf("#define dsMatchStart (%3u)(%%rdi)\n",(int)(((char*)&(s->match_start))-((char*)s)));
-printf("#define dsLookahead (%3u)(%%rdi)\n",(int)(((char*)&(s->lookahead))-((char*)s)));
-printf("#define dsPrevLen (%3u)(%%rdi)\n",(int)(((char*)&(s->prev_length))-((char*)s)));
-printf("#define dsMaxChainLen (%3u)(%%rdi)\n",(int)(((char*)&(s->max_chain_length))-((char*)s)));
-printf("#define dsGoodMatch (%3u)(%%rdi)\n",(int)(((char*)&(s->good_match))-((char*)s)));
-printf("#define dsNiceMatch (%3u)(%%rdi)\n",(int)(((char*)&(s->nice_match))-((char*)s)));
-}
-
-*/
-
-
-/*
- to compile for XCode 3.2 on MacOSX x86_64
- - run "gcc -g -c -DXCODE_MAC_X64_STRUCTURE amd64-match.S"
- */
-
-
-#ifndef CURRENT_LINX_XCODE_MAC_X64_STRUCTURE
-#define dsWSize ( 68)(%rdi)
-#define dsWMask ( 76)(%rdi)
-#define dsWindow ( 80)(%rdi)
-#define dsPrev ( 96)(%rdi)
-#define dsMatchLen (144)(%rdi)
-#define dsPrevMatch (148)(%rdi)
-#define dsStrStart (156)(%rdi)
-#define dsMatchStart (160)(%rdi)
-#define dsLookahead (164)(%rdi)
-#define dsPrevLen (168)(%rdi)
-#define dsMaxChainLen (172)(%rdi)
-#define dsGoodMatch (188)(%rdi)
-#define dsNiceMatch (192)(%rdi)
-
-#else
-
-#ifndef STRUCT_OFFSET
-# define STRUCT_OFFSET (0)
-#endif
-
-
-#define dsWSize ( 56 + STRUCT_OFFSET)(%rdi)
-#define dsWMask ( 64 + STRUCT_OFFSET)(%rdi)
-#define dsWindow ( 72 + STRUCT_OFFSET)(%rdi)
-#define dsPrev ( 88 + STRUCT_OFFSET)(%rdi)
-#define dsMatchLen (136 + STRUCT_OFFSET)(%rdi)
-#define dsPrevMatch (140 + STRUCT_OFFSET)(%rdi)
-#define dsStrStart (148 + STRUCT_OFFSET)(%rdi)
-#define dsMatchStart (152 + STRUCT_OFFSET)(%rdi)
-#define dsLookahead (156 + STRUCT_OFFSET)(%rdi)
-#define dsPrevLen (160 + STRUCT_OFFSET)(%rdi)
-#define dsMaxChainLen (164 + STRUCT_OFFSET)(%rdi)
-#define dsGoodMatch (180 + STRUCT_OFFSET)(%rdi)
-#define dsNiceMatch (184 + STRUCT_OFFSET)(%rdi)
-
-#endif
-
-
-
-
-.text
-
-/* uInt longest_match(deflate_state *deflatestate, IPos curmatch) */
-
-longest_match:
-/*
- * Retrieve the function arguments. %curmatch will hold cur_match
- * throughout the entire function (passed via rsi on amd64).
- * rdi will hold the pointer to the deflate_state (first arg on amd64)
- */
- mov %rsi, save_rsi
- mov %rbx, save_rbx
- mov %r12, save_r12
- mov %r13, save_r13
- mov %r14, save_r14
- mov %r15, save_r15
-
-/* uInt wmask = s->w_mask; */
-/* unsigned chain_length = s->max_chain_length; */
-/* if (s->prev_length >= s->good_match) { */
-/* chain_length >>= 2; */
-/* } */
-
- movl dsPrevLen, %eax
- movl dsGoodMatch, %ebx
- cmpl %ebx, %eax
- movl dsWMask, %eax
- movl dsMaxChainLen, %chainlenwmask
- jl LastMatchGood
- shrl $2, %chainlenwmask
-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. */
-
- decl %chainlenwmask
- shll $16, %chainlenwmask
- orl %eax, %chainlenwmask
-
-/* if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; */
-
- movl dsNiceMatch, %eax
- movl dsLookahead, %ebx
- cmpl %eax, %ebx
- jl LookaheadLess
- movl %eax, %ebx
-LookaheadLess: movl %ebx, %nicematch
-
-/* register Bytef *scan = s->window + s->strstart; */
-
- mov dsWindow, %window
- movl dsStrStart, %limitd
- lea (%limit, %window), %scan
-
-/* Determine how many bytes the scan ptr is off from being */
-/* dword-aligned. */
-
- mov %scan, %scanalign
- negl %scanalignd
- andl $3, %scanalignd
-
-/* IPos limit = s->strstart > (IPos)MAX_DIST(s) ? */
-/* s->strstart - (IPos)MAX_DIST(s) : NIL; */
-
- movl dsWSize, %eax
- subl $MIN_LOOKAHEAD, %eax
- xorl %ecx, %ecx
- subl %eax, %limitd
- cmovng %ecx, %limitd
-
-/* int best_len = s->prev_length; */
-
- movl dsPrevLen, %bestlend
-
-/* Store the sum of s->window + best_len in %windowbestlen locally, and in memory. */
-
- lea (%window, %bestlen), %windowbestlen
- mov %windowbestlen, _windowbestlen
-
-/* register ush scan_start = *(ushf*)scan; */
-/* register ush scan_end = *(ushf*)(scan+best_len-1); */
-/* Posf *prev = s->prev; */
-
- movzwl (%scan), %scanstart
- movzwl -1(%scan, %bestlen), %scanend
- mov dsPrev, %prev
-
-/* Jump into the main loop. */
-
- movl %chainlenwmask, _chainlenwmask
- jmp LoopEntry
-
-.balign 16
-
-/* 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.
- */
-LookupLoop:
- andl %chainlenwmask, %curmatchd
- movzwl (%prev, %curmatch, 2), %curmatchd
- cmpl %limitd, %curmatchd
- jbe LeaveNow
- subl $0x00010000, %chainlenwmask
- js LeaveNow
-LoopEntry: cmpw -1(%windowbestlen, %curmatch), %scanendw
- jne LookupLoop
- cmpw %scanstartw, (%window, %curmatch)
- jne LookupLoop
-
-/* Store the current value of chainlen. */
- movl %chainlenwmask, _chainlenwmask
-
-/* %scan is the string under scrutiny, and %prev 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 $(-MAX_MATCH_8), %rdx
- lea (%curmatch, %window), %windowbestlen
- lea MAX_MATCH_8(%windowbestlen, %scanalign), %windowbestlen
- lea MAX_MATCH_8(%scan, %scanalign), %prev
-
-/* the prefetching below makes very little difference... */
- prefetcht1 (%windowbestlen, %rdx)
- prefetcht1 (%prev, %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.
- *
- * 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 -- unrolling it, for example, makes no difference.
- */
-
-#undef USE_SSE /* works, but is 6-7% slower, than non-SSE... */
-
-LoopCmps:
-#ifdef USE_SSE
- /* Preload the SSE registers */
- movdqu (%windowbestlen, %rdx), %xmm1
- movdqu (%prev, %rdx), %xmm2
- pcmpeqb %xmm2, %xmm1
- movdqu 16(%windowbestlen, %rdx), %xmm3
- movdqu 16(%prev, %rdx), %xmm4
- pcmpeqb %xmm4, %xmm3
- movdqu 32(%windowbestlen, %rdx), %xmm5
- movdqu 32(%prev, %rdx), %xmm6
- pcmpeqb %xmm6, %xmm5
- movdqu 48(%windowbestlen, %rdx), %xmm7
- movdqu 48(%prev, %rdx), %xmm8
- pcmpeqb %xmm8, %xmm7
-
- /* Check the comparisions' results */
- pmovmskb %xmm1, %rax
- notw %ax
- bsfw %ax, %ax
- jnz LeaveLoopCmps
-
- /* this is the only iteration of the loop with a possibility of having
- incremented rdx by 0x108 (each loop iteration add 16*4 = 0x40
- and (0x40*4)+8=0x108 */
- add $8, %rdx
- jz LenMaximum
- add $8, %rdx
-
-
- pmovmskb %xmm3, %rax
- notw %ax
- bsfw %ax, %ax
- jnz LeaveLoopCmps
-
-
- add $16, %rdx
-
-
- pmovmskb %xmm5, %rax
- notw %ax
- bsfw %ax, %ax
- jnz LeaveLoopCmps
-
- add $16, %rdx
-
-
- pmovmskb %xmm7, %rax
- notw %ax
- bsfw %ax, %ax
- jnz LeaveLoopCmps
-
- add $16, %rdx
-
- jmp LoopCmps
-LeaveLoopCmps: add %rax, %rdx
-#else
- mov (%windowbestlen, %rdx), %rax
- xor (%prev, %rdx), %rax
- jnz LeaveLoopCmps
-
- mov 8(%windowbestlen, %rdx), %rax
- xor 8(%prev, %rdx), %rax
- jnz LeaveLoopCmps8
-
- mov 16(%windowbestlen, %rdx), %rax
- xor 16(%prev, %rdx), %rax
- jnz LeaveLoopCmps16
-
- add $24, %rdx
- jnz LoopCmps
- jmp LenMaximum
-# if 0
-/*
- * This three-liner is tantalizingly simple, but bsf is a slow instruction,
- * and the complicated alternative down below is quite a bit faster. Sad...
- */
-
-LeaveLoopCmps: bsf %rax, %rax /* find the first non-zero bit */
- shrl $3, %eax /* divide by 8 to get the byte */
- add %rax, %rdx
-# else
-LeaveLoopCmps16:
- add $8, %rdx
-LeaveLoopCmps8:
- add $8, %rdx
-LeaveLoopCmps: testl $0xFFFFFFFF, %eax /* Check the first 4 bytes */
- jnz Check16
- add $4, %rdx
- shr $32, %rax
-Check16: testw $0xFFFF, %ax
- jnz LenLower
- add $2, %rdx
- shrl $16, %eax
-LenLower: subb $1, %al
- adc $0, %rdx
-# endif
-#endif
-
-/* 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 (%prev, %rdx), %rax
- sub %scan, %rax
- cmpl $MAX_MATCH, %eax
- 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. */
-
- cmpl %bestlend, %eax
- jg LongerMatch
- mov _windowbestlen, %windowbestlen
- mov dsPrev, %prev
- movl _chainlenwmask, %edx
- jmp LookupLoop
-
-/* s->match_start = cur_match; */
-/* best_len = len; */
-/* if (len >= nice_match) break; */
-/* scan_end = *(ushf*)(scan+best_len-1); */
-
-LongerMatch:
- movl %eax, %bestlend
- movl %curmatchd, dsMatchStart
- cmpl %nicematch, %eax
- jge LeaveNow
-
- lea (%window, %bestlen), %windowbestlen
- mov %windowbestlen, _windowbestlen
-
- movzwl -1(%scan, %rax), %scanend
- mov dsPrev, %prev
- movl _chainlenwmask, %chainlenwmask
- jmp LookupLoop
-
-/* Accept the current string, with the maximum possible length. */
-
-LenMaximum:
- movl $MAX_MATCH, %bestlend
- movl %curmatchd, dsMatchStart
-
-/* if ((uInt)best_len <= s->lookahead) return (uInt)best_len; */
-/* return s->lookahead; */
-
-LeaveNow:
- movl dsLookahead, %eax
- cmpl %eax, %bestlend
- cmovngl %bestlend, %eax
-LookaheadRet:
-
-/* Restore the registers and return from whence we came. */
-
- mov save_rsi, %rsi
- mov save_rbx, %rbx
- mov save_r12, %r12
- mov save_r13, %r13
- mov save_r14, %r14
- mov save_r15, %r15
-
- ret
-
-match_init: ret
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