From 2acd2a2f57f27d6e9ded396f0e8cf720f7ac19b6 Mon Sep 17 00:00:00 2001
From: Stefan Lankes <lankes@lfbs.rwth-aachen.de>
Date: Sat, 27 Aug 2011 05:24:28 -0700
Subject: [PATCH] add SCC optimized memset function

---
 arch/x86/include/asm/string.h | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/string.h b/arch/x86/include/asm/string.h
index e1c092b7..66f5e617 100644
--- a/arch/x86/include/asm/string.h
+++ b/arch/x86/include/asm/string.h
@@ -117,9 +117,37 @@ inline static void *memcpy(void* dest, const void *src, size_t count)
 
 #ifdef HAVE_ARCH_MEMSET
 
+#ifdef CONFIG_ROCKCREEK
 /** @brief Repeated write of a value to a whole range of bytes
  *
- * Writes a value repeatedly double word wise (4 byte) to a range of bytes
+ * SCC optimized version of memset (see memcpy)
+ *
+ * @param dest Destination address
+ * @param val Value to flood the range with
+ * @param count Size of target range in bytes
+ */
+inline static void *memset(void* dest, int val, size_t count)
+{
+	int32_t i, j;
+
+	if (BUILTIN_EXPECT(!dest, 0))
+		return dest;
+
+	asm volatile ("cld\n\t"
+		"1: cmpl $32, %%ebx ; jb 2f\n\t"
+		"movl (%%edi), %%edx\n\t"
+		"movl $32, %%ecx\n\t"
+		"rep stosb\n\t"
+		"subl $32, %%ebx\n\t"
+		"jmp 1b\n\t"
+		"2: movl %%ebx, %%ecx ; rep stosb"
+		: "=&b"(i), "=&D"(j)
+		: "a"(val), "1"(dest), "0"(count) :  "%edx", "%ecx", "memory","cc");
+
+	return dest;
+}
+#else
+/** @brief Repeated write of a value to a whole range of bytes
  *
  * @param dest Destination address
  * @param val Value to flood the range with
@@ -140,6 +168,8 @@ inline static void *memset(void* dest, int val, size_t count)
 }
 #endif
 
+#endif
+
 #ifdef HAVE_ARCH_STRLEN
 
 /** @brief Standard string length