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glibc/sysdeps/i386/i686/memcmp.S
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/* Compare two memory blocks for differences in the first COUNT bytes. | |
Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
The GNU C Library is free software; you can redistribute it and/or | |
modify it under the terms of the GNU Lesser General Public | |
License as published by the Free Software Foundation; either | |
version 2.1 of the License, or (at your option) any later version. | |
The GNU C Library is distributed in the hope that it will be useful, | |
but WITHOUT ANY WARRANTY; without even the implied warranty of | |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
Lesser General Public License for more details. | |
You should have received a copy of the GNU Lesser General Public | |
License along with the GNU C Library; if not, write to the Free | |
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
02111-1307 USA. */ | |
#include <sysdep.h> | |
#include "asm-syntax.h" | |
#include "bp-sym.h" | |
#include "bp-asm.h" | |
#define PARMS LINKAGE+4 /* Preserve EBX. */ | |
#define BLK1 PARMS | |
#define BLK2 BLK1+PTR_SIZE | |
#define LEN BLK2+PTR_SIZE | |
#define ENTRANCE pushl %ebx; cfi_adjust_cfa_offset (4); \ | |
cfi_rel_offset (ebx, 0); ENTER | |
#define RETURN popl %ebx; cfi_adjust_cfa_offset (-4); \ | |
cfi_restore (ebx); LEAVE; ret; \ | |
cfi_adjust_cfa_offset (4); cfi_rel_offset (ebx, 0); | |
/* Load an entry in a jump table into EBX. TABLE is a jump table | |
with relative offsets. INDEX is a register contains the index | |
into the jump table. */ | |
#define LOAD_JUMP_TABLE_ENTRY(TABLE, INDEX) \ | |
/* We first load PC into EBX. */ \ | |
call __i686.get_pc_thunk.bx; \ | |
/* Get the address of the jump table. */ \ | |
addl $(TABLE - .), %ebx; \ | |
/* Get the entry and convert the relative offset to the \ | |
absolute address. */ \ | |
addl (%ebx,INDEX,4), %ebx | |
.section .gnu.linkonce.t.__i686.get_pc_thunk.bx,"ax",@progbits | |
.globl __i686.get_pc_thunk.bx | |
.hidden __i686.get_pc_thunk.bx | |
ALIGN (4) | |
.type __i686.get_pc_thunk.bx,@function | |
__i686.get_pc_thunk.bx: | |
movl (%esp), %ebx | |
ret | |
.text | |
ALIGN (4) | |
ENTRY (BP_SYM (memcmp)) | |
ENTRANCE | |
movl BLK1(%esp), %eax | |
movl BLK2(%esp), %edx | |
movl LEN(%esp), %ecx | |
cmpl $1, %ecx | |
jne L(not_1) | |
movzbl (%eax), %ecx /* LEN == 1 */ | |
cmpb (%edx), %cl | |
jne L(neq) | |
L(bye): | |
xorl %eax, %eax | |
RETURN | |
L(neq): | |
sbbl %eax, %eax | |
sbbl $-1, %eax | |
RETURN | |
cfi_adjust_cfa_offset (4) | |
cfi_rel_offset (ebx, 0) | |
L(not_1): | |
jl L(bye) /* LEN == 0 */ | |
pushl %esi | |
cfi_adjust_cfa_offset (4) | |
movl %eax, %esi | |
cfi_rel_offset (esi, 0) | |
cmpl $32, %ecx; | |
jge L(32bytesormore) /* LEN => 32 */ | |
LOAD_JUMP_TABLE_ENTRY (L(table_32bytes), %ecx) | |
addl %ecx, %edx | |
addl %ecx, %esi | |
jmp *%ebx | |
ALIGN (4) | |
L(28bytes): | |
movl -28(%esi), %eax | |
movl -28(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(24bytes): | |
movl -24(%esi), %eax | |
movl -24(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(20bytes): | |
movl -20(%esi), %eax | |
movl -20(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(16bytes): | |
movl -16(%esi), %eax | |
movl -16(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(12bytes): | |
movl -12(%esi), %eax | |
movl -12(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(8bytes): | |
movl -8(%esi), %eax | |
movl -8(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(4bytes): | |
movl -4(%esi), %eax | |
movl -4(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(0bytes): | |
popl %esi | |
cfi_adjust_cfa_offset (-4) | |
cfi_restore (esi) | |
xorl %eax, %eax | |
RETURN | |
cfi_adjust_cfa_offset (8) | |
cfi_rel_offset (esi, 0) | |
cfi_rel_offset (ebx, 4) | |
L(29bytes): | |
movl -29(%esi), %eax | |
movl -29(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(25bytes): | |
movl -25(%esi), %eax | |
movl -25(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(21bytes): | |
movl -21(%esi), %eax | |
movl -21(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(17bytes): | |
movl -17(%esi), %eax | |
movl -17(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(13bytes): | |
movl -13(%esi), %eax | |
movl -13(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(9bytes): | |
movl -9(%esi), %eax | |
movl -9(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(5bytes): | |
movl -5(%esi), %eax | |
movl -5(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(1bytes): | |
movzbl -1(%esi), %eax | |
cmpb -1(%edx), %al | |
jne L(set) | |
popl %esi | |
cfi_adjust_cfa_offset (-4) | |
cfi_restore (esi) | |
xorl %eax, %eax | |
RETURN | |
cfi_adjust_cfa_offset (8) | |
cfi_rel_offset (esi, 0) | |
cfi_rel_offset (ebx, 4) | |
L(30bytes): | |
movl -30(%esi), %eax | |
movl -30(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(26bytes): | |
movl -26(%esi), %eax | |
movl -26(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(22bytes): | |
movl -22(%esi), %eax | |
movl -22(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(18bytes): | |
movl -18(%esi), %eax | |
movl -18(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(14bytes): | |
movl -14(%esi), %eax | |
movl -14(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(10bytes): | |
movl -10(%esi), %eax | |
movl -10(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(6bytes): | |
movl -6(%esi), %eax | |
movl -6(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(2bytes): | |
movzwl -2(%esi), %eax | |
movzwl -2(%edx), %ecx | |
cmpb %cl, %al | |
jne L(set) | |
cmpl %ecx, %eax | |
jne L(set) | |
popl %esi | |
cfi_adjust_cfa_offset (-4) | |
cfi_restore (esi) | |
xorl %eax, %eax | |
RETURN | |
cfi_adjust_cfa_offset (8) | |
cfi_rel_offset (esi, 0) | |
cfi_rel_offset (ebx, 4) | |
L(31bytes): | |
movl -31(%esi), %eax | |
movl -31(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(27bytes): | |
movl -27(%esi), %eax | |
movl -27(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(23bytes): | |
movl -23(%esi), %eax | |
movl -23(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(19bytes): | |
movl -19(%esi), %eax | |
movl -19(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(15bytes): | |
movl -15(%esi), %eax | |
movl -15(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(11bytes): | |
movl -11(%esi), %eax | |
movl -11(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(7bytes): | |
movl -7(%esi), %eax | |
movl -7(%edx), %ecx | |
cmpl %ecx, %eax | |
jne L(find_diff) | |
L(3bytes): | |
movzwl -3(%esi), %eax | |
movzwl -3(%edx), %ecx | |
cmpb %cl, %al | |
jne L(set) | |
cmpl %ecx, %eax | |
jne L(set) | |
movzbl -1(%esi), %eax | |
cmpb -1(%edx), %al | |
jne L(set) | |
popl %esi | |
cfi_adjust_cfa_offset (-4) | |
cfi_restore (esi) | |
xorl %eax, %eax | |
RETURN | |
cfi_adjust_cfa_offset (8) | |
cfi_rel_offset (esi, 0) | |
cfi_rel_offset (ebx, 4) | |
ALIGN (4) | |
/* ECX >= 32. */ | |
L(32bytesormore): | |
subl $32, %ecx | |
movl (%esi), %eax | |
cmpl (%edx), %eax | |
jne L(load_ecx) | |
movl 4(%esi), %eax | |
cmpl 4(%edx), %eax | |
jne L(load_ecx_4) | |
movl 8(%esi), %eax | |
cmpl 8(%edx), %eax | |
jne L(load_ecx_8) | |
movl 12(%esi), %eax | |
cmpl 12(%edx), %eax | |
jne L(load_ecx_12) | |
movl 16(%esi), %eax | |
cmpl 16(%edx), %eax | |
jne L(load_ecx_16) | |
movl 20(%esi), %eax | |
cmpl 20(%edx), %eax | |
jne L(load_ecx_20) | |
movl 24(%esi), %eax | |
cmpl 24(%edx), %eax | |
jne L(load_ecx_24) | |
movl 28(%esi), %eax | |
cmpl 28(%edx), %eax | |
jne L(load_ecx_28) | |
addl $32, %esi | |
addl $32, %edx | |
cmpl $32, %ecx | |
jge L(32bytesormore) | |
LOAD_JUMP_TABLE_ENTRY (L(table_32bytes), %ecx) | |
addl %ecx, %edx | |
addl %ecx, %esi | |
jmp *%ebx | |
L(load_ecx_28): | |
addl $0x4, %edx | |
L(load_ecx_24): | |
addl $0x4, %edx | |
L(load_ecx_20): | |
addl $0x4, %edx | |
L(load_ecx_16): | |
addl $0x4, %edx | |
L(load_ecx_12): | |
addl $0x4, %edx | |
L(load_ecx_8): | |
addl $0x4, %edx | |
L(load_ecx_4): | |
addl $0x4, %edx | |
L(load_ecx): | |
movl (%edx), %ecx | |
L(find_diff): | |
cmpb %cl, %al | |
jne L(set) | |
cmpb %ch, %ah | |
jne L(set) | |
shrl $16,%eax | |
shrl $16,%ecx | |
cmpb %cl, %al | |
jne L(set) | |
/* We get there only if we already know there is a | |
difference. */ | |
cmpl %ecx, %eax | |
L(set): | |
sbbl %eax, %eax | |
sbbl $-1, %eax | |
popl %esi | |
cfi_adjust_cfa_offset (-4) | |
cfi_restore (esi) | |
RETURN | |
END (BP_SYM (memcmp)) | |
.section .rodata | |
ALIGN (2) | |
L(table_32bytes) : | |
.long L(0bytes) - L(table_32bytes) | |
.long L(1bytes) - L(table_32bytes) | |
.long L(2bytes) - L(table_32bytes) | |
.long L(3bytes) - L(table_32bytes) | |
.long L(4bytes) - L(table_32bytes) | |
.long L(5bytes) - L(table_32bytes) | |
.long L(6bytes) - L(table_32bytes) | |
.long L(7bytes) - L(table_32bytes) | |
.long L(8bytes) - L(table_32bytes) | |
.long L(9bytes) - L(table_32bytes) | |
.long L(10bytes) - L(table_32bytes) | |
.long L(11bytes) - L(table_32bytes) | |
.long L(12bytes) - L(table_32bytes) | |
.long L(13bytes) - L(table_32bytes) | |
.long L(14bytes) - L(table_32bytes) | |
.long L(15bytes) - L(table_32bytes) | |
.long L(16bytes) - L(table_32bytes) | |
.long L(17bytes) - L(table_32bytes) | |
.long L(18bytes) - L(table_32bytes) | |
.long L(19bytes) - L(table_32bytes) | |
.long L(20bytes) - L(table_32bytes) | |
.long L(21bytes) - L(table_32bytes) | |
.long L(22bytes) - L(table_32bytes) | |
.long L(23bytes) - L(table_32bytes) | |
.long L(24bytes) - L(table_32bytes) | |
.long L(25bytes) - L(table_32bytes) | |
.long L(26bytes) - L(table_32bytes) | |
.long L(27bytes) - L(table_32bytes) | |
.long L(28bytes) - L(table_32bytes) | |
.long L(29bytes) - L(table_32bytes) | |
.long L(30bytes) - L(table_32bytes) | |
.long L(31bytes) - L(table_32bytes) | |
#undef bcmp | |
weak_alias (BP_SYM (memcmp), BP_SYM (bcmp)) | |
libc_hidden_builtin_def (BP_SYM (memcmp)) |