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Diffstat (limited to 'zlib/contrib/amd64/amd64-match.S')
| -rw-r--r-- | zlib/contrib/amd64/amd64-match.S | 452 |
1 files changed, 452 insertions, 0 deletions
diff --git a/zlib/contrib/amd64/amd64-match.S b/zlib/contrib/amd64/amd64-match.S new file mode 100644 index 0000000..81d4a1c --- /dev/null +++ b/zlib/contrib/amd64/amd64-match.S @@ -0,0 +1,452 @@ +/* + * 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 |