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122 lines
3.1 KiB
ArmAsm
122 lines
3.1 KiB
ArmAsm
/* memset/bzero -- set memory area to CH/0
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Highly optimized version for ix86, x>=5.
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Copyright (C) 1996-2013 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Torbjorn Granlund, <tege@matematik.su.se>
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include "asm-syntax.h"
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/* BEWARE: `#ifdef memset' means that memset is redefined as `bzero' */
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#define BZERO_P (defined memset)
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#define PARMS 4+4 /* space for 1 saved reg */
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#define RTN PARMS
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#define DEST RTN
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#if BZERO_P
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# define LEN DEST+4
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#else
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# define CHR DEST+4
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# define LEN CHR+4
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#endif
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.text
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#if defined PIC && !defined NOT_IN_libc && !BZERO_P
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ENTRY (__memset_chk)
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movl 12(%esp), %eax
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cmpl %eax, 16(%esp)
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jb HIDDEN_JUMPTARGET (__chk_fail)
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END (__memset_chk)
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#endif
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ENTRY (memset)
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pushl %edi
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cfi_adjust_cfa_offset (4)
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movl DEST(%esp), %edi
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cfi_rel_offset (edi, 0)
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movl LEN(%esp), %edx
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#if BZERO_P
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xorl %eax, %eax /* we fill with 0 */
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#else
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movb CHR(%esp), %al
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movb %al, %ah
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movl %eax, %ecx
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shll $16, %eax
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movw %cx, %ax
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#endif
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cld
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/* If less than 36 bytes to write, skip tricky code (it wouldn't work). */
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cmpl $36, %edx
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movl %edx, %ecx /* needed when branch is taken! */
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jl L(2)
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/* First write 0-3 bytes to make the pointer 32-bit aligned. */
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movl %edi, %ecx /* Copy ptr to ecx... */
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negl %ecx /* ...and negate that and... */
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andl $3, %ecx /* ...mask to get byte count. */
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subl %ecx, %edx /* adjust global byte count */
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rep
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stosb
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subl $32, %edx /* offset count for unrolled loop */
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movl (%edi), %ecx /* Fetch destination cache line */
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.align 2, 0x90 /* supply 0x90 for broken assemblers */
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L(1): movl 28(%edi), %ecx /* allocate cache line for destination */
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subl $32, %edx /* decr loop count */
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movl %eax, 0(%edi) /* store words pairwise */
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movl %eax, 4(%edi)
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movl %eax, 8(%edi)
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movl %eax, 12(%edi)
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movl %eax, 16(%edi)
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movl %eax, 20(%edi)
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movl %eax, 24(%edi)
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movl %eax, 28(%edi)
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leal 32(%edi), %edi /* update destination pointer */
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jge L(1)
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leal 32(%edx), %ecx /* reset offset count */
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/* Write last 0-7 full 32-bit words (up to 8 words if loop was skipped). */
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L(2): shrl $2, %ecx /* convert byte count to longword count */
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rep
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stosl
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/* Finally write the last 0-3 bytes. */
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movl %edx, %ecx
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andl $3, %ecx
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rep
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stosb
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#if !BZERO_P
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/* Load result (only if used as memset). */
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movl DEST(%esp), %eax /* start address of destination is result */
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#endif
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popl %edi
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cfi_adjust_cfa_offset (-4)
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cfi_restore (edi)
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#if BZERO_P
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ret
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#else
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ret
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#endif
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END (memset)
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libc_hidden_builtin_def (memset)
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