diff options
Diffstat (limited to 'sysdeps/i386/i686/memcmp.S')
| -rw-r--r-- | sysdeps/i386/i686/memcmp.S | 392 |
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)) |