diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 8f7bef8e9fff..23f315c9f215 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -229,18 +229,35 @@ void *memset(void *s, int c, size_t n)
 		ss[i] = c;
 	return s;
 }
-
+#ifdef CONFIG_X86_32
 void *memcpy(void *dest, const void *src, size_t n)
 {
-	int i;
-	const char *s = src;
-	char *d = dest;
+	int 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");
 
-	for (i = 0; i < n; i++)
-		d[i] = s[i];
 	return dest;
 }
+#else
+void *memcpy(void *dest, const void *src, size_t n)
+{
+	long d0, d1, d2;
+	asm volatile(
+		"rep ; movsq\n\t"
+		"movq %4,%%rcx\n\t"
+		"rep ; movsb\n\t"
+		: "=&c" (d0), "=&D" (d1), "=&S" (d2)
+		: "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
+		: "memory");
 
+	return dest;
+}
+#endif
 
 static void error(char *x)
 {