bitkeeper revision 1.1343 (42669573FPZbSiupGqFkPopp_NRfpA)

Make the fallback memset/memcpy/memmove have a concrete in-place
implementation, or we end up with a recursive dependency when building
for x86/64.
Signed-off-by: Keir Fraser <keir@xensource.com>

1 files changed, 42 insertions, 6 deletions

diff --git a/xen/arch/x86/string.c b/xen/arch/x86/string.c
index 5a7788ba11..b45a9197d5 100644
--- a/xen/arch/x86/string.c
+++ b/xen/arch/x86/string.c
@@ -9,19 +9,55 @@
 #include <xen/lib.h>
 
 #undef memmove
-void *memmove(void *dest, const void *src, size_t count)
+void *memmove(void *dest, const void *src, size_t n)
 {
-    return __memmove(dest, src, count);
+    int d0, d1, d2;
+ 
+    if ( dest < src )
+        return memcpy(dest, src, n);
+
+    __asm__ __volatile__ (
+        "   std         ; "
+        "   rep ; movsb ; "
+        "   cld           "
+        : "=&c" (d0), "=&S" (d1), "=&D" (d2)
+        : "0" (n), "1" (n-1+(const char *)src), "2" (n-1+(char *)dest)
+        : "memory");
+
+    return dest;
 }
 
 #undef memcpy
-void *memcpy(void *dest, const void *src, size_t count)
+void *memcpy(void *dest, const void *src, size_t n)
 {
-    return __memcpy(dest, src, count);
+    int d0, d1, d2;
+
+    __asm__ __volatile__ (
+        "   rep ; movsl      ; "
+        "   testb $2,%b4     ; "
+        "   je 1f            ; "
+        "   movsw            ; "
+        "1: testb $1,%b4     ; "
+        "   je 2f            ; "
+        "   movsb            ; "
+        "2:                    "
+        : "=&c" (d0), "=&D" (d1), "=&S" (d2)
+        : "0" (n/4), "q" (n), "1" (dest), "2" (src)
+        : "memory");
+
+    return dest;
 }
 
 #undef memset
-void *memset(void *s, int c, size_t count)
+void *memset(void *s, int c, size_t n)
 {
-    return __memset(s, c, count);
+    int d0, d1;
+
+    __asm__ __volatile__ (
+        "rep ; stosb"
+        : "=&c" (d0), "=&D" (d1)
+        : "a" (c), "1" (s), "0" (n)
+        : "memory");
+
+    return s;
 }