patch-2.3.6 linux/arch/alpha/lib/memcpy.c

• Lines: 155
• Date: Mon Jun 7 11:37:13 1999
• Orig file: v2.3.5/linux/arch/alpha/lib/memcpy.c
• Orig date: Tue Apr 7 08:05:05 1998

diff -u --recursive --new-file v2.3.5/linux/arch/alpha/lib/memcpy.c linux/arch/alpha/lib/memcpy.c
@@ -21,30 +21,44 @@
  * This should be done in one go with ldq_u*2/mask/stq_u. Do it
  * with a macro so that we can fix it up later..
  */
-#define ALIGN_DEST_TO8(d,s,n) \
+#define ALIGN_DEST_TO8_UP(d,s,n) \
 	while (d & 7) { \
 		if (n <= 0) return; \
 		n--; \
 		*(char *) d = *(char *) s; \
 		d++; s++; \
 	}
+#define ALIGN_DEST_TO8_DN(d,s,n) \
+	while (d & 7) { \
+		if (n <= 0) return; \
+		n--; \
+		d--; s--; \
+		*(char *) d = *(char *) s; \
+	}
 
 /*
  * This should similarly be done with ldq_u*2/mask/stq. The destination
  * is aligned, but we don't fill in a full quad-word
  */
-#define DO_REST(d,s,n) \
+#define DO_REST_UP(d,s,n) \
 	while (n > 0) { \
 		n--; \
 		*(char *) d = *(char *) s; \
 		d++; s++; \
 	}
+#define DO_REST_DN(d,s,n) \
+	while (n > 0) { \
+		n--; \
+		d--; s--; \
+		*(char *) d = *(char *) s; \
+	}
 
 /*
  * This should be done with ldq/mask/stq. The source and destination are
  * aligned, but we don't fill in a full quad-word
  */
-#define DO_REST_ALIGNED(d,s,n) DO_REST(d,s,n)
+#define DO_REST_ALIGNED_UP(d,s,n) DO_REST_UP(d,s,n)
+#define DO_REST_ALIGNED_DN(d,s,n) DO_REST_DN(d,s,n)
 
 /*
  * This does unaligned memory copies. We want to avoid storing to
@@ -53,9 +67,10 @@
  *
  * Note the ordering to try to avoid load (and address generation) latencies.
  */
-static inline void __memcpy_unaligned(unsigned long d, unsigned long s, long n)
+static inline void __memcpy_unaligned_up (unsigned long d, unsigned long s,
+					  long n)
 {
-	ALIGN_DEST_TO8(d,s,n);
+	ALIGN_DEST_TO8_UP(d,s,n);
 	n -= 8;			/* to avoid compare against 8 in the loop */
 	if (n >= 0) {
 		unsigned long low_word, high_word;
@@ -77,7 +92,17 @@
 		} while (n >= 0);
 	}
 	n += 8;
-	DO_REST(d,s,n);
+	DO_REST_UP(d,s,n);
+}
+
+static inline void __memcpy_unaligned_dn (unsigned long d, unsigned long s,
+					  long n)
+{
+	/* I don't understand AXP assembler well enough for this. -Tim */
+	s += n;
+	d += n;
+	while (n--)
+		* (char *) --d = * (char *) --s;
 }
 
 /*
@@ -88,9 +113,10 @@
  *
  * Note the ordering to try to avoid load (and address generation) latencies.
  */
-static inline void __memcpy_aligned(unsigned long d, unsigned long s, long n)
+static inline void __memcpy_aligned_up (unsigned long d, unsigned long s,
+					long n)
 {
-	ALIGN_DEST_TO8(d,s,n);
+	ALIGN_DEST_TO8_UP(d,s,n);
 	n -= 8;
 	while (n >= 0) {
 		unsigned long tmp;
@@ -101,18 +127,58 @@
 		d += 8;
 	}
 	n += 8;
-	DO_REST_ALIGNED(d,s,n);
+	DO_REST_ALIGNED_UP(d,s,n);
+}
+static inline void __memcpy_aligned_dn (unsigned long d, unsigned long s,
+					long n)
+{
+	s += n;
+	d += n;
+	ALIGN_DEST_TO8_DN(d,s,n);
+	n -= 8;
+	while (n >= 0) {
+		unsigned long tmp;
+		s -= 8;
+		__asm__("ldq %0,%1":"=r" (tmp):"m" (*(unsigned long *) s));
+		n -= 8;
+		d -= 8;
+		*(unsigned long *) d = tmp;
+	}
+	n += 8;
+	DO_REST_ALIGNED_DN(d,s,n);
 }
 
 void * memcpy(void * dest, const void *src, size_t n)
 {
 	if (!(((unsigned long) dest ^ (unsigned long) src) & 7)) {
-		__memcpy_aligned((unsigned long) dest, (unsigned long) src, n);
+		__memcpy_aligned_up ((unsigned long) dest, (unsigned long) src,
+				     n);
 		return dest;
 	}
-	__memcpy_unaligned((unsigned long) dest, (unsigned long) src, n);
+	__memcpy_unaligned_up ((unsigned long) dest, (unsigned long) src, n);
 	return dest;
 }
 
 /* For backward modules compatibility, define __memcpy.  */
 asm("__memcpy = memcpy; .globl __memcpy");
+
+void *memmove (void *dest, const void *src, size_t n)
+{
+	if (dest <= src) {
+		if (!(((unsigned long) dest ^ (unsigned long) src) & 7))
+			__memcpy_aligned_up ((unsigned long) dest,
+					     (unsigned long) src, n);
+		else
+			__memcpy_unaligned_up ((unsigned long) dest,
+					       (unsigned long) src, n);
+	}
+	else {
+		if (!(((unsigned long) dest ^ (unsigned long) src) & 7))
+			__memcpy_aligned_dn ((unsigned long) dest,
+					     (unsigned long) src, n);
+		else
+			__memcpy_unaligned_dn ((unsigned long) dest,
+					       (unsigned long) src, n);
+	}
+	return dest;
+}