diff options
Diffstat (limited to 'REORG.TODO/sysdeps/i386/i586/memset.S')
| -rw-r--r-- | REORG.TODO/sysdeps/i386/i586/memset.S | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/i386/i586/memset.S b/REORG.TODO/sysdeps/i386/i586/memset.S new file mode 100644 index 0000000000..4f8f1bcf94 --- /dev/null +++ b/REORG.TODO/sysdeps/i386/i586/memset.S @@ -0,0 +1,121 @@ +/* memset/bzero -- set memory area to CH/0 + Highly optimized version for ix86, x>=5. + Copyright (C) 1996-2017 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, see + <http://www.gnu.org/licenses/>. */ + +#include <sysdep.h> +#include "asm-syntax.h" + +#define PARMS 4+4 /* space for 1 saved reg */ +#define RTN PARMS +#define DEST RTN +#ifdef USE_AS_BZERO +# define LEN DEST+4 +#else +# define CHR DEST+4 +# define LEN CHR+4 +#endif + + .text +#if defined SHARED && IS_IN (libc) && !defined USE_AS_BZERO +ENTRY (__memset_chk) + movl 12(%esp), %eax + cmpl %eax, 16(%esp) + jb HIDDEN_JUMPTARGET (__chk_fail) +END (__memset_chk) +#endif +ENTRY (memset) + + pushl %edi + cfi_adjust_cfa_offset (4) + + movl DEST(%esp), %edi + cfi_rel_offset (edi, 0) + movl LEN(%esp), %edx +#ifdef USE_AS_BZERO + 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 + +#ifndef USE_AS_BZERO + /* Load result (only if used as memset). */ + movl DEST(%esp), %eax /* start address of destination is result */ +#endif + popl %edi + cfi_adjust_cfa_offset (-4) + cfi_restore (edi) + + ret +END (memset) +libc_hidden_builtin_def (memset) + +#if defined SHARED && IS_IN (libc) && !defined __memset_chk \ + && !defined USE_AS_BZERO +strong_alias (__memset_chk, __memset_zero_constant_len_parameter) + .section .gnu.warning.__memset_zero_constant_len_parameter + .string "memset used with constant zero length parameter; this could be due to transposed parameters" +#endif |