| /* memset/bzero -- set memory area to CH/0 |
| Highly optimized version for ix86, x>=5. |
| Copyright (C) 1996, 1997, 2000, 2003, 2005 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Torbjorn Granlund, <tege@matematik.su.se> |
| |
| 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" |
| |
| /* BEWARE: `#ifdef memset' means that memset is redefined as `bzero' */ |
| #define BZERO_P (defined memset) |
| |
| #define PARMS LINKAGE+4 /* space for 1 saved reg */ |
| #define RTN PARMS |
| #define DEST RTN+RTN_SIZE |
| #if BZERO_P |
| # define LEN DEST+PTR_SIZE |
| #else |
| # define CHR DEST+PTR_SIZE |
| # define LEN CHR+4 |
| #endif |
| |
| .text |
| #if defined PIC && !defined NOT_IN_libc && !BZERO_P |
| ENTRY (__memset_chk) |
| movl 12(%esp), %eax |
| cmpl %eax, 16(%esp) |
| jb HIDDEN_JUMPTARGET (__chk_fail) |
| END (__memset_chk) |
| #endif |
| ENTRY (BP_SYM (memset)) |
| ENTER |
| |
| pushl %edi |
| cfi_adjust_cfa_offset (4) |
| |
| movl DEST(%esp), %edi |
| cfi_rel_offset (edi, 0) |
| movl LEN(%esp), %edx |
| CHECK_BOUNDS_BOTH_WIDE (%edi, DEST(%esp), %edx) |
| #if BZERO_P |
| xorl %eax, %eax /* we fill with 0 */ |
| #else |
| movb CHR(%esp), %al |
| movb %al, %ah |
| movl %eax, %ecx |
| shll $16, %eax |
| movw %cx, %ax |
| #endif |
| cld |
| |
| /* If less than 36 bytes to write, skip tricky code (it wouldn't work). */ |
| cmpl $36, %edx |
| movl %edx, %ecx /* needed when branch is taken! */ |
| jl L(2) |
| |
| /* First write 0-3 bytes to make the pointer 32-bit aligned. */ |
| movl %edi, %ecx /* Copy ptr to ecx... */ |
| negl %ecx /* ...and negate that and... */ |
| andl $3, %ecx /* ...mask to get byte count. */ |
| subl %ecx, %edx /* adjust global byte count */ |
| rep |
| stosb |
| |
| subl $32, %edx /* offset count for unrolled loop */ |
| movl (%edi), %ecx /* Fetch destination cache line */ |
| |
| .align 2, 0x90 /* supply 0x90 for broken assemblers */ |
| L(1): movl 28(%edi), %ecx /* allocate cache line for destination */ |
| subl $32, %edx /* decr loop count */ |
| movl %eax, 0(%edi) /* store words pairwise */ |
| movl %eax, 4(%edi) |
| movl %eax, 8(%edi) |
| movl %eax, 12(%edi) |
| movl %eax, 16(%edi) |
| movl %eax, 20(%edi) |
| movl %eax, 24(%edi) |
| movl %eax, 28(%edi) |
| leal 32(%edi), %edi /* update destination pointer */ |
| jge L(1) |
| |
| leal 32(%edx), %ecx /* reset offset count */ |
| |
| /* Write last 0-7 full 32-bit words (up to 8 words if loop was skipped). */ |
| L(2): shrl $2, %ecx /* convert byte count to longword count */ |
| rep |
| stosl |
| |
| /* Finally write the last 0-3 bytes. */ |
| movl %edx, %ecx |
| andl $3, %ecx |
| rep |
| stosb |
| |
| #if !BZERO_P |
| /* Load result (only if used as memset). */ |
| movl DEST(%esp), %eax /* start address of destination is result */ |
| RETURN_BOUNDED_POINTER (DEST(%esp)) |
| #endif |
| popl %edi |
| cfi_adjust_cfa_offset (-4) |
| cfi_restore (edi) |
| |
| LEAVE |
| #if BZERO_P |
| ret |
| #else |
| RET_PTR |
| #endif |
| END (BP_SYM (memset)) |
| libc_hidden_builtin_def (memset) |
