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/* Compare two memory blocks for differences in the first COUNT bytes.
Copyright (C) 2004-2014 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, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include "asm-syntax.h"
#define PARMS 4+4 /* Preserve EBX. */
#define BLK1 PARMS
#define BLK2 BLK1+4
#define LEN BLK2+4
#define ENTRANCE pushl %ebx; cfi_adjust_cfa_offset (4); \
cfi_rel_offset (ebx, 0)
#define RETURN popl %ebx; cfi_adjust_cfa_offset (-4); \
cfi_restore (ebx); ret
/* 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. */ \
SETUP_PIC_REG(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
.text
ALIGN (4)
ENTRY (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
cfi_adjust_cfa_offset (4)
cfi_rel_offset (ebx, 0)
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 (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 (memcmp, bcmp)
libc_hidden_builtin_def (memcmp)
|
