1 files changed, 78 insertions, 0 deletions
diff --git a/src/lib/memcpy.c b/src/lib/memcpy.c
new file mode 100755
index 0000000..ab508ea
--- /dev/null
+++ b/src/lib/memcpy.c
@@ -0,0 +1,78 @@
+// $Id: memcpy.c,v 1.1.1.1 2013/12/11 20:49:20 bcbrock Exp $
+// $Source: /afs/awd/projects/eclipz/KnowledgeBase/.cvsroot/eclipz/chips/p8/working/procedures/lib/memcpy.c,v $
+//-----------------------------------------------------------------------------
+// *! (C) Copyright International Business Machines Corp. 2013
+// *! All Rights Reserved -- Property of IBM
+// *! *** IBM Confidential ***
+//-----------------------------------------------------------------------------
+
+/// \file memcpy.c
+/// \brief The memcpy() function
+
+#include "ssx.h"
+
+/// The memcpy() function copies \a n bytes from memory area \a src to memory
+/// area \a dest.  The memory areas should not overlap.  Use memmove(3) if the
+/// memory areas do overlap. The memcpy() function returns a pointer to dest.
+
+// This implementation should work well for both 32-bit and 64-bit machines,
+// assuming they can handle unaligned accesses. The implementation assumes that
+// it is better to avoid the loop setup overhead by a test and branch for
+// cases where loops can be bypassed.
+
+//void *
+//memcpy(void *dest, const void *src, size_t n)
+//{
+//    while(n--) {
+//      *dest++ = *src++;
+//    }
+//
+//    return s;
+//}
+
+void *
+memcpy(void *dest, const void *src, size_t n)
+{
+    uint8_t *d8, *s8;
+    uint64_t *d64, *s64;
+    size_t doublewords, octawords;
+
+    // First copy memory 32 bytes at a time.
+
+    d64 = (uint64_t *)dest;
+    s64 = (uint64_t *)src;
+    octawords = n / 32;
+    if (octawords) {
+        n -= octawords * 32;
+        while(octawords--) {
+            *d64++ = *s64++;
+            *d64++ = *s64++;
+            *d64++ = *s64++;
+            *d64++ = *s64++;
+        }
+    }
+
+    // Now set memory 8 bytes at a time. This might actually be better done
+    // explicitly rather than as a loop because the maximum loop count is 3
+    // here. 
+
+    doublewords = n / 8;
+    if (doublewords) {
+        n -= doublewords * 8;
+        while (doublewords--) {
+            *d64++ = *s64++;
+        }
+    }
+
+    // Finally finish any remaining memory bytewise
+
+    if (n) {
+        d8 = (uint8_t *)d64;
+        s8 = (uint8_t *)s64;
+        while (n--) {
+            *d8++ = *s8++;
+        }
+    }
+
+    return dest;
+}