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authorGabe Black <gabeblack@google.com>2012-09-27 17:42:23 -0700
committerStefan Reinauer <stefan.reinauer@coreboot.org>2012-11-07 18:31:15 +0100
commit3b84086e3dc5ff9e50a1ea847fd7dac2e687d471 (patch)
treee3ce3d56cc60e33332652feb206e1f22a7b1459c
parentc324794cb09d0c6495992c9f6cece6e4c67f8c9f (diff)
libpayload: Add faster, architecture specific versions of memset and memcpy.
Change-Id: I0f3a82de860fd3afa10a557b37fb90fe6b06ae90 Signed-off-by: Gabe Black <gabeblack@google.com> Reviewed-on: http://review.coreboot.org/1726 Reviewed-by: Patrick Georgi <patrick@georgi-clan.de> Tested-by: build bot (Jenkins)
-rw-r--r--payloads/libpayload/arch/i386/Makefile.inc1
-rw-r--r--payloads/libpayload/arch/i386/string.c103
2 files changed, 104 insertions, 0 deletions
diff --git a/payloads/libpayload/arch/i386/Makefile.inc b/payloads/libpayload/arch/i386/Makefile.inc
index 2be5e54783..8f68b07709 100644
--- a/payloads/libpayload/arch/i386/Makefile.inc
+++ b/payloads/libpayload/arch/i386/Makefile.inc
@@ -31,6 +31,7 @@ head.o-y += head.S
libc-y += main.c sysinfo.c
libc-y += timer.c coreboot.c util.S
libc-y += exec.S virtual.c
+libc-y += string.c
# Multiboot support is configurable
libc-$(CONFIG_MULTIBOOT) += multiboot.c
diff --git a/payloads/libpayload/arch/i386/string.c b/payloads/libpayload/arch/i386/string.c
new file mode 100644
index 0000000000..19047eee9e
--- /dev/null
+++ b/payloads/libpayload/arch/i386/string.c
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 1991,1992,1993,1997,1998,2003, 2005 Free Software Foundation, Inc.
+ * This file is part of the GNU C Library.
+ * Copyright (c) 2011 The Chromium OS Authors.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 (at your option) 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/* From glibc-2.14, sysdeps/i386/memset.c */
+
+#include <stdint.h>
+
+#include "string.h"
+
+typedef uint32_t op_t;
+
+void *memset(void *dstpp, int c, size_t len)
+{
+ int d0;
+ unsigned long int dstp = (unsigned long int) dstpp;
+
+ /* This explicit register allocation improves code very much indeed. */
+ register op_t x asm("ax");
+
+ x = (unsigned char) c;
+
+ /* Clear the direction flag, so filling will move forward. */
+ asm volatile("cld");
+
+ /* This threshold value is optimal. */
+ if (len >= 12) {
+ /* Fill X with four copies of the char we want to fill with. */
+ x |= (x << 8);
+ x |= (x << 16);
+
+ /* Adjust LEN for the bytes handled in the first loop. */
+ len -= (-dstp) % sizeof(op_t);
+
+ /*
+ * There are at least some bytes to set. No need to test for
+ * LEN == 0 in this alignment loop.
+ */
+
+ /* Fill bytes until DSTP is aligned on a longword boundary. */
+ asm volatile(
+ "rep\n"
+ "stosb" /* %0, %2, %3 */ :
+ "=D" (dstp), "=c" (d0) :
+ "0" (dstp), "1" ((-dstp) % sizeof(op_t)), "a" (x) :
+ "memory");
+
+ /* Fill longwords. */
+ asm volatile(
+ "rep\n"
+ "stosl" /* %0, %2, %3 */ :
+ "=D" (dstp), "=c" (d0) :
+ "0" (dstp), "1" (len / sizeof(op_t)), "a" (x) :
+ "memory");
+ len %= sizeof(op_t);
+ }
+
+ /* Write the last few bytes. */
+ asm volatile(
+ "rep\n"
+ "stosb" /* %0, %2, %3 */ :
+ "=D" (dstp), "=c" (d0) :
+ "0" (dstp), "1" (len), "a" (x) :
+ "memory");
+
+ return dstpp;
+}
+
+void *memcpy(void *dest, const void *src, size_t n)
+{
+ unsigned long d0, d1, d2;
+
+ asm volatile(
+ "rep ; movsl\n\t"
+ "movl %4,%%ecx\n\t"
+ "rep ; movsb\n\t"
+ : "=&c" (d0), "=&D" (d1), "=&S" (d2)
+ : "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
+ : "memory"
+ );
+
+ return dest;
+}