merge x86_64 optimized string support

1 files changed, 95 insertions, 0 deletions

diff --git a/libc/string/x86_64/memcpy.S b/libc/string/x86_64/memcpy.S
new file mode 100644
index 000000000..4fa38a640
--- /dev/null
+++ b/libc/string/x86_64/memcpy.S
@@ -0,0 +1,95 @@
+/* Highly optimized version for x86-64.
+   Copyright (C) 1997, 2000, 2002, 2003, 2004 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Based on i586 version contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+   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 "_glibc_inc.h"
+
+/* BEWARE: `#ifdef memcpy' means that memcpy is redefined as `mempcpy',
+   and the return value is the byte after the last one copied in
+   the destination. */
+#define MEMPCPY_P (defined memcpy)
+
+        .text
+#if defined PIC && !defined NOT_IN_libc
+ENTRY (__memcpy_chk)
+	cmpq	%rdx, %rcx
+	jb	HIDDEN_JUMPTARGET (__chk_fail)
+END (__memcpy_chk)
+#endif
+ENTRY (BP_SYM (memcpy))
+	/* Cutoff for the big loop is a size of 32 bytes since otherwise
+	   the loop will never be entered.  */
+	cmpq	$32, %rdx
+	movq	%rdx, %rcx
+#if !MEMPCPY_P
+	movq	%rdi, %r10	/* Save value. */
+#endif
+
+	/* We need this in any case.  */
+	cld
+
+	jbe	1f
+
+	/* Align destination.  */
+	movq	%rdi, %rax
+	negq	%rax
+	andq	$7, %rax
+	subq	%rax, %rcx
+	xchgq	%rax, %rcx
+
+	rep; movsb
+
+	movq	%rax, %rcx
+	subq	$32, %rcx
+	js	2f
+
+	.p2align 4
+3:
+
+	/* Now correct the loop counter.  Please note that in the following
+	   code the flags are not changed anymore.  */
+	subq	$32, %rcx
+
+	movq	(%rsi), %rax
+	movq	8(%rsi), %rdx
+	movq	16(%rsi), %r8
+	movq	24(%rsi), %r9
+	movq	%rax, (%rdi)
+	movq	%rdx, 8(%rdi)
+	movq	%r8, 16(%rdi)
+	movq	%r9, 24(%rdi)
+
+	leaq	32(%rsi), %rsi
+	leaq	32(%rdi), %rdi
+
+	jns	3b
+
+	/* Correct extra loop counter modification.  */
+2:	addq	$32, %rcx
+1:	rep; movsb
+
+#if MEMPCPY_P
+	movq	%rdi, %rax		/* Set return value.  */
+#else
+	movq	%r10, %rax		/* Set return value.  */
+	
+#endif
+	ret
+
+END (BP_SYM (memcpy))