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diff --git a/qemu/roms/ipxe/src/arch/x86/core/x86_string.c b/qemu/roms/ipxe/src/arch/x86/core/x86_string.c
new file mode 100644
index 000000000..d48347c96
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/x86/core/x86_string.c
@@ -0,0 +1,190 @@
+/*
+ * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+/** @file
+ *
+ * Optimised string operations
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <string.h>
+
+/**
+ * Copy memory area
+ *
+ * @v dest		Destination address
+ * @v src		Source address
+ * @v len		Length
+ * @ret dest		Destination address
+ */
+void * __attribute__ (( noinline )) __memcpy ( void *dest, const void *src,
+					       size_t len ) {
+	void *edi = dest;
+	const void *esi = src;
+	int discard_ecx;
+
+	/* We often do large dword-aligned and dword-length block
+	 * moves.  Using movsl rather than movsb speeds these up by
+	 * around 32%.
+	 */
+	__asm__ __volatile__ ( "rep movsl"
+			       : "=&D" ( edi ), "=&S" ( esi ),
+				 "=&c" ( discard_ecx )
+			       : "0" ( edi ), "1" ( esi ), "2" ( len >> 2 )
+			       : "memory" );
+	__asm__ __volatile__ ( "rep movsb"
+			       : "=&D" ( edi ), "=&S" ( esi ),
+				 "=&c" ( discard_ecx )
+			       : "0" ( edi ), "1" ( esi ), "2" ( len & 3 )
+			       : "memory" );
+	return dest;
+}
+
+/**
+ * Copy memory area backwards
+ *
+ * @v dest		Destination address
+ * @v src		Source address
+ * @v len		Length
+ * @ret dest		Destination address
+ */
+void * __attribute__ (( noinline )) __memcpy_reverse ( void *dest,
+						       const void *src,
+						       size_t len ) {
+	void *edi = ( dest + len - 1 );
+	const void *esi = ( src + len - 1 );
+	int discard_ecx;
+
+	/* Assume memmove() is not performance-critical, and perform a
+	 * bytewise copy for simplicity.
+	 */
+	__asm__ __volatile__ ( "std\n\t"
+			       "rep movsb\n\t"
+			       "cld\n\t"
+			       : "=&D" ( edi ), "=&S" ( esi ),
+				 "=&c" ( discard_ecx )
+			       : "0" ( edi ), "1" ( esi ),
+				 "2" ( len )
+			       : "memory" );
+	return dest;
+}
+
+
+/**
+ * Copy (possibly overlapping) memory area
+ *
+ * @v dest		Destination address
+ * @v src		Source address
+ * @v len		Length
+ * @ret dest		Destination address
+ */
+void * __memmove ( void *dest, const void *src, size_t len ) {
+
+	if ( dest <= src ) {
+		return __memcpy ( dest, src, len );
+	} else {
+		return __memcpy_reverse ( dest, src, len );
+	}
+}
+
+/**
+ * Swap memory areas
+ *
+ * @v dest		Destination address
+ * @v src		Source address
+ * @v len		Length
+ * @ret dest		Destination address
+ */
+void * memswap ( void *dest, void *src, size_t len ) {
+	size_t discard_c;
+	int discard;
+
+	__asm__ __volatile__ ( "\n1:\n\t"
+			       "dec %2\n\t"
+			       "js 2f\n\t"
+			       "movb (%0,%2), %b3\n\t"
+			       "xchgb (%1,%2), %b3\n\t"
+			       "movb %b3, (%0,%2)\n\t"
+			       "jmp 1b\n\t"
+			       "2:\n\t"
+			       : "=r" ( src ), "=r" ( dest ),
+				 "=&c" ( discard_c ), "=&q" ( discard )
+			       : "0" ( src ), "1" ( dest ), "2" ( len )
+			       : "memory" );
+
+	return dest;
+}
+
+/**
+ * Calculate length of string
+ *
+ * @v string		String
+ * @ret len		Length (excluding NUL)
+ */
+size_t strlen ( const char *string ) {
+	const char *discard_D;
+	size_t len_plus_one;
+
+	__asm__ __volatile__ ( "repne scasb\n\t"
+			       "not %1\n\t"
+			       : "=&D" ( discard_D ), "=&c" ( len_plus_one )
+			       : "0" ( string ), "1" ( -1UL ), "a" ( 0 ) );
+
+	return ( len_plus_one - 1 );
+}
+
+/**
+ * Compare strings (up to a specified length)
+ *
+ * @v str1		First string
+ * @v str2		Second string
+ * @v len		Maximum length
+ * @ret diff		Difference
+ */
+int strncmp ( const char *str1, const char *str2, size_t len ) {
+	const void *discard_S;
+	const void *discard_D;
+	size_t discard_c;
+	int diff;
+
+	__asm__ __volatile__ ( "\n1:\n\t"
+			       "dec %2\n\t"
+			       "js 2f\n\t"
+			       "lodsb\n\t"
+			       "scasb\n\t"
+			       "jne 3f\n\t"
+			       "testb %b3, %b3\n\t"
+			       "jnz 1b\n\t"
+			       /* Equal */
+			       "\n2:\n\t"
+			       "xor %3, %3\n\t"
+			       "jmp 4f\n\t"
+			       /* Not equal; CF indicates difference */
+			       "\n3:\n\t"
+			       "sbb %3, %3\n\t"
+			       "orb $1, %b3\n\t"
+			       "\n4:\n\t"
+			       : "=&S" ( discard_S ), "=&D" ( discard_D ),
+				 "=&c" ( discard_c ), "=&a" ( diff )
+			       : "0" ( str1 ), "1" ( str2 ), "2" ( len ) );
+
+	return diff;
+}