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authorUlrich Drepper <drepper@redhat.com>2004-02-10 01:55:34 +0000
committerUlrich Drepper <drepper@redhat.com>2004-02-10 01:55:34 +0000
commit221c6b37b5f0fdb9cfcd2579798209d31987323c (patch)
treeab16b0cb922bda145b6a666efa239f15eee2ccfc /sysdeps/i386
parentc655f8f8516484d5a401ea5982921703b50e87e5 (diff)
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memcmp optimized for i686.
Diffstat (limited to 'sysdeps/i386')
-rw-r--r--sysdeps/i386/i686/memcmp.S392
1 files changed, 392 insertions, 0 deletions
diff --git a/sysdeps/i386/i686/memcmp.S b/sysdeps/i386/i686/memcmp.S
new file mode 100644
index 0000000000..920ae72df3
--- /dev/null
+++ b/sysdeps/i386/i686/memcmp.S
@@ -0,0 +1,392 @@
+/* Compare two memory blocks for differences in the first COUNT bytes.
+ Copyright (C) 2004 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; ENTER
+#define RETURN popl %ebx; LEAVE; 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. */ \
+ 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
+
+#ifdef HAVE_HIDDEN
+ .section .gnu.linkonce.t.__i686.get_pc_thunk.bx,"ax",@progbits
+ .globl __i686.get_pc_thunk.bx
+ .hidden __i686.get_pc_thunk.bx
+#else
+ .text
+#endif
+ 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
+
+L(not_1):
+ jl L(bye) /* LEN == 0 */
+
+ pushl %esi
+ movl %eax, %esi
+ 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
+ xorl %eax, %eax
+ RETURN
+
+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
+ xorl %eax, %eax
+ RETURN
+
+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
+ xorl %eax, %eax
+ RETURN
+
+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
+ xorl %eax, %eax
+ RETURN
+
+ 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
+ RETURN
+
+ ALIGN (2)
+L(table_32bytes) :
+ .long L(0bytes) - . + 0x0
+ .long L(1bytes) - . + 0x4
+ .long L(2bytes) - . + 0x8
+ .long L(3bytes) - . + 0xc
+ .long L(4bytes) - . + 0x10
+ .long L(5bytes) - . + 0x14
+ .long L(6bytes) - . + 0x18
+ .long L(7bytes) - . + 0x1c
+ .long L(8bytes) - . + 0x20
+ .long L(9bytes) - . + 0x24
+ .long L(10bytes) - . + 0x28
+ .long L(11bytes) - . + 0x2c
+ .long L(12bytes) - . + 0x30
+ .long L(13bytes) - . + 0x34
+ .long L(14bytes) - . + 0x38
+ .long L(15bytes) - . + 0x3c
+ .long L(16bytes) - . + 0x40
+ .long L(17bytes) - . + 0x44
+ .long L(18bytes) - . + 0x48
+ .long L(19bytes) - . + 0x4c
+ .long L(20bytes) - . + 0x50
+ .long L(21bytes) - . + 0x54
+ .long L(22bytes) - . + 0x58
+ .long L(23bytes) - . + 0x5c
+ .long L(24bytes) - . + 0x60
+ .long L(25bytes) - . + 0x64
+ .long L(26bytes) - . + 0x68
+ .long L(27bytes) - . + 0x6c
+ .long L(28bytes) - . + 0x70
+ .long L(29bytes) - . + 0x74
+ .long L(30bytes) - . + 0x78
+ .long L(31bytes) - . + 0x7c
+
+END (BP_SYM (memcmp))
+
+#undef bcmp
+weak_alias (BP_SYM (memcmp), BP_SYM (bcmp))