patch-2.4.22 linux-2.4.22/arch/sh64/lib/memcpy.c

• Lines: 83
• Date: 2003-08-25 04:44:40.000000000 -0700
• Orig file: linux-2.4.21/arch/sh64/lib/memcpy.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.21/arch/sh64/lib/memcpy.c linux-2.4.22/arch/sh64/lib/memcpy.c
@@ -0,0 +1,82 @@
+/* 
+ * Copyright (C) 2002 Mark Debbage (Mark.Debbage@superh.com)
+ *
+ * May be copied or modified under the terms of the GNU General Public
+ * License.  See linux/COPYING for more information.                            
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <asm/string.h>
+
+// This is a simplistic optimization of memcpy to increase the
+// granularity of access beyond one byte using aligned 
+// loads and stores. This is not an optimal implementation
+// for SH-5 (especially with regard to prefetching and the cache), 
+// and a better version should be provided later ...
+
+void *memcpy(void *dest, const void *src, size_t count)
+{
+	char *d = (char *) dest, *s = (char *) src;
+
+	if (count >= 32) {
+		int i = 8 - (((unsigned long) d) & 0x7);
+
+		if (i != 8)
+			while (i-- && count--) {
+				*d++ = *s++;
+			}
+
+		if (((((unsigned long) d) & 0x7) == 0) &&
+		    ((((unsigned long) s) & 0x7) == 0)) {
+			while (count >= 32) {
+				unsigned long long t1, t2, t3, t4;
+				t1 = *(unsigned long long *) (s);
+				t2 = *(unsigned long long *) (s + 8);
+				t3 = *(unsigned long long *) (s + 16);
+				t4 = *(unsigned long long *) (s + 24);
+				*(unsigned long long *) (d) = t1;
+				*(unsigned long long *) (d + 8) = t2;
+				*(unsigned long long *) (d + 16) = t3;
+				*(unsigned long long *) (d + 24) = t4;
+				d += 32;
+				s += 32;
+				count -= 32;
+			}
+			while (count >= 8) {
+				*(unsigned long long *) d =
+				    *(unsigned long long *) s;
+				d += 8;
+				s += 8;
+				count -= 8;
+			}
+		}
+
+		if (((((unsigned long) d) & 0x3) == 0) &&
+		    ((((unsigned long) s) & 0x3) == 0)) {
+			while (count >= 4) {
+				*(unsigned long *) d = *(unsigned long *) s;
+				d += 4;
+				s += 4;
+				count -= 4;
+			}
+		}
+
+		if (((((unsigned long) d) & 0x1) == 0) &&
+		    ((((unsigned long) s) & 0x1) == 0)) {
+			while (count >= 2) {
+				*(unsigned short *) d = *(unsigned short *) s;
+				d += 2;
+				s += 2;
+				count -= 2;
+			}
+		}
+	}
+
+	while (count--) {
+		*d++ = *s++;
+	}
+
+	return d;
+}