Add 64-bit Silvermont-optimized string/memory functions.

Add following functions:
bcopy, bzero, memcpy, memmove, memset, stpcpy, stpncpy, strcat, strcpy,
strlen, strncat, strncpy, memcmp, strcmp, strncmp.
Set all these functions as the default ones.

Change-Id: Ic66b250ad8c349a43d25e2d4dea075604f6df6ac
Signed-off-by: Varvara Rainchik <varvara.rainchik@intel.com>
diff --git a/libc/arch-x86_64/string/sse2-strcat-slm.S b/libc/arch-x86_64/string/sse2-strcat-slm.S
new file mode 100644
index 0000000..dd8207f
--- /dev/null
+++ b/libc/arch-x86_64/string/sse2-strcat-slm.S
@@ -0,0 +1,87 @@
+/*

+Copyright (c) 2014, Intel Corporation

+All rights reserved.

+

+Redistribution and use in source and binary forms, with or without

+modification, are permitted provided that the following conditions are met:

+

+    * Redistributions of source code must retain the above copyright notice,

+    * this list of conditions and the following disclaimer.

+

+    * Redistributions in binary form must reproduce the above copyright notice,

+    * this list of conditions and the following disclaimer in the documentation

+    * and/or other materials provided with the distribution.

+

+    * Neither the name of Intel Corporation nor the names of its contributors

+    * may be used to endorse or promote products derived from this software

+    * without specific prior written permission.

+

+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND

+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR

+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON

+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

+*/

+

+#ifndef STRCAT

+# define STRCAT		strcat

+#endif

+

+#ifndef L

+# define L(label)		.L##label

+#endif

+

+#ifndef cfi_startproc

+# define cfi_startproc		 .cfi_startproc

+#endif

+

+#ifndef cfi_endproc

+# define cfi_endproc		.cfi_endproc

+#endif

+

+#ifndef ENTRY

+# define ENTRY(name)		\

+	.type name,  @function;		\

+	.globl name;		\

+	.p2align 4;		\

+name:		\

+	cfi_startproc

+#endif

+

+#ifndef END

+# define END(name)		\

+	cfi_endproc;		\

+	.size name, .-name

+#endif

+

+#define USE_AS_STRCAT

+

+.text

+ENTRY (STRCAT)

+	mov	%rdi, %r9

+#ifdef USE_AS_STRNCAT

+	mov	%rdx, %r8

+#endif

+

+#define RETURN jmp L(Strcpy)

+#include "sse2-strlen-slm.S"

+

+#undef RETURN

+#define RETURN ret

+

+L(Strcpy):

+	lea	(%r9, %rax), %rdi

+	mov	%rsi, %rcx

+	mov	%r9, %rax	/* save result */

+

+#ifdef USE_AS_STRNCAT

+	test	%r8, %r8

+	jz	L(ExitZero)

+# define USE_AS_STRNCPY

+#endif

+#include "sse2-strcpy-slm.S"