[libc] Provide an unoptimised generic_memcpy_reverse()

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 20 insertions, 5 deletions

diff --git a/src/core/string.c b/src/core/string.c
index 5bd9dae..c35015b 100644
--- a/src/core/string.c
+++ b/src/core/string.c
@@ -52,7 +52,7 @@ void * generic_memset ( void *dest, int character, size_t len ) {
 }
 
 /**
- * Copy memory region
+ * Copy memory region (forwards)
  *
  * @v dest		Destination region
  * @v src		Source region
@@ -69,25 +69,40 @@ void * generic_memcpy ( void *dest, const void *src, size_t len ) {
 }
 
 /**
- * Copy (possibly overlapping) memory region
+ * Copy memory region (backwards)
  *
  * @v dest		Destination region
  * @v src		Source region
  * @v len		Length
  * @ret dest		Destination region
  */
-void * generic_memmove ( void *dest, const void *src, size_t len ) {
+void * generic_memcpy_reverse ( void *dest, const void *src, size_t len ) {
 	const uint8_t *src_bytes = ( src + len );
 	uint8_t *dest_bytes = ( dest + len );
 
-	if ( dest < src )
-		return generic_memcpy ( dest, src, len );
 	while ( len-- )
 		*(--dest_bytes) = *(--src_bytes);
 	return dest;
 }
 
 /**
+ * Copy (possibly overlapping) memory region
+ *
+ * @v dest		Destination region
+ * @v src		Source region
+ * @v len		Length
+ * @ret dest		Destination region
+ */
+void * generic_memmove ( void *dest, const void *src, size_t len ) {
+
+	if ( dest < src ) {
+		return generic_memcpy ( dest, src, len );
+	} else {
+		return generic_memcpy_reverse ( dest, src, len );
+	}
+}
+
+/**
  * Compare memory regions
  *
  * @v first		First region