mirror of git://sourceware.org/git/glibc.git
132 lines
3.0 KiB
ArmAsm
132 lines
3.0 KiB
ArmAsm
/* memset/bzero -- set memory area to CH/0
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Optimized version for x86-64.
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Copyright (C) 2002 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Andreas Jaeger <aj@suse.de>.
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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, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <sysdep.h>
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#include "asm-syntax.h"
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#include "bp-sym.h"
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#include "bp-asm.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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/* This is somehow experimental and could made dependend on the cache
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size. */
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#define LARGE $120000
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.text
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ENTRY (memset)
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#if BZERO_P
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mov %rsi,%rdx /* Adjust parameter. */
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xorq %rsi,%rsi /* Fill with 0s. */
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#endif
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cmp $0x7,%rdx /* Check for small length. */
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mov %rdi,%rcx /* Save ptr as return value. */
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jbe 7f
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#if BZERO_P
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mov %rsi,%r8 /* Just copy 0. */
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#else
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/* Populate 8 bit data to full 64-bit. */
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movabs $0x0101010101010101,%r8
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movzbl %sil,%eax
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imul %rax,%r8
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#endif
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test $0x7,%edi /* Check for alignment. */
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je 2f
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.p2align 4
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1: /* Align ptr to 8 byte. */
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mov %sil,(%rcx)
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dec %rdx
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inc %rcx
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test $0x7,%ecx
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jne 1b
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2: /* Check for really large regions. */
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mov %rdx,%rax
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shr $0x6,%rax
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je 4f
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cmp LARGE, %rdx
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jae 11f
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.p2align 4
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3: /* Copy 64 bytes. */
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mov %r8,(%rcx)
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mov %r8,0x8(%rcx)
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mov %r8,0x10(%rcx)
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mov %r8,0x18(%rcx)
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mov %r8,0x20(%rcx)
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mov %r8,0x28(%rcx)
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mov %r8,0x30(%rcx)
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mov %r8,0x38(%rcx)
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add $0x40,%rcx
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dec %rax
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jne 3b
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4: /* Copy final bytes. */
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and $0x3f,%edx
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mov %rdx,%rax
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shr $0x3,%rax
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je 6f
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5: /* First in chunks of 8 bytes. */
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mov %r8,(%rcx)
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add $0x8,%rcx
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dec %rax
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jne 5b
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6:
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and $0x7,%edx
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7:
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test %rdx,%rdx
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je 9f
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8: /* And finally as bytes (up to 7). */
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mov %sil,(%rcx)
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inc %rcx
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dec %rdx
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jne 8b
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9:
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#if BZERO_P
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nop
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#else
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/* Load result (only if used as memset). */
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mov %rdi,%rax /* start address of destination is result */
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#endif
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retq
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.p2align 4
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11: /* Copy 64 bytes without polluting the cache. */
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/* We could use movntdq %xmm0,(%rcx) here to further
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speed up for large cases but let's not use XMM registers. */
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movnti %r8,(%rcx)
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movnti %r8,0x8(%rcx)
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movnti %r8,0x10(%rcx)
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movnti %r8,0x18(%rcx)
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movnti %r8,0x20(%rcx)
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movnti %r8,0x28(%rcx)
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movnti %r8,0x30(%rcx)
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movnti %r8,0x38(%rcx)
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add $0x40,%rcx
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dec %rax
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jne 11b
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jmp 4b
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END (memset)
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