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Diffstat (limited to 'sysdeps/i386/i586/memset.S')
| -rw-r--r-- | sysdeps/i386/i586/memset.S | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/sysdeps/i386/i586/memset.S b/sysdeps/i386/i586/memset.S new file mode 100644 index 0000000000..3a68fa16d1 --- /dev/null +++ b/sysdeps/i386/i586/memset.S @@ -0,0 +1,101 @@ +/* memset/bzero -- set memory area to CH/0 +Highly optimized version for ix85, x>=5. +Copyright (C) 1996 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 Library General Public License as +published by the Free Software Foundation; either version 2 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 +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, +Boston, MA 02111-1307, USA. */ + +#include <sysdep.h> + +/* + INPUT PARAMETERS: + (memset) (bzero) + dst (sp + 4) dst (sp + 4) + ch (sp + 8) len (sp + 8) + len (sp + 12) +*/ + + + .text +ENTRY (memset) + pushl %edi + + movl 8(%esp), %edi /* destination pointer */ +#ifdef memset + xorl %eax, %eax /* we fill with 0 */ + movl 12(%esp), %edx /* size (in 8-bit words) */ +#else + movb 12(%esp), %al /* use CH to fill */ + movl 16(%esp), %edx /* size (in 8-bit words) */ + + 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 L2 + +/* 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 */ +L1: 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 L1 + + leal 32(%edx), %ecx /* reset offset count */ + +/* Write last 0-7 full 32-bit words (up to 8 words if loop was skipped). */ +L2: 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 + + /* Load result (only if used as memset). */ +#ifndef memset + movl 8(%esp), %eax +#endif + popl %edi + + ret |