1 files changed, 76 insertions, 0 deletions
diff --git a/libc/string/powerpc/memmove.c b/libc/string/powerpc/memmove.c
new file mode 100644
index 000000000..28b1da270
--- /dev/null
+++ b/libc/string/powerpc/memmove.c
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2004 Joakim Tjernlund
+ * Copyright (C) 2000-2005 Erik Andersen <andersen@uclibc.org>
+ *
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
+ */
+
+/* These are carefully optimized mem*() functions for PPC written in C.
+ * Don't muck around with these function without checking the generated
+ * assmbler code.
+ * It is possible to optimize these significantly more by using specific
+ * data cache instructions(mainly dcbz). However that requires knownledge
+ * about the CPU's cache line size.
+ *
+ * BUG ALERT!
+ * The cache instructions on MPC8xx CPU's are buggy(they don't update
+ * the DAR register when causing a DTLB Miss/Error) and cannot be
+ * used on 8xx CPU's without a kernel patch to work around this
+ * problem.
+ */
+
+#include <string.h>
+
+void attribute_hidden *__memmove(void *to, const void *from, size_t n)
+{
+	unsigned long rem, chunks, tmp1, tmp2;
+	unsigned char *tmp_to;
+	unsigned char *tmp_from = (unsigned char *)from;
+
+	if (tmp_from >= (unsigned char *)to)
+		return __memcpy(to, from, n);
+	chunks = n / 8;
+	tmp_from += n;
+	tmp_to = to + n;
+	if (!chunks)
+		goto lessthan8;
+	rem = (unsigned long )tmp_to % 4;
+	if (rem)
+		goto align;
+ copy_chunks:
+	do {
+		/* make gcc to load all data, then store it */
+		tmp1 = *(unsigned long *)(tmp_from-4);
+		tmp_from -= 8;
+		tmp2 = *(unsigned long *)tmp_from;
+		*(unsigned long *)(tmp_to-4) = tmp1;
+		tmp_to -= 8;
+		*(unsigned long *)tmp_to = tmp2;
+	} while (--chunks);
+ lessthan8:
+	n = n % 8;
+	if (n >= 4) {
+		*(unsigned long *)(tmp_to-4) = *(unsigned long *)(tmp_from-4);
+		tmp_from -= 4;
+		tmp_to -= 4;
+		n = n-4;
+	}
+	if (!n ) return to;
+	do {
+		*--tmp_to = *--tmp_from;
+	} while (--n);
+	
+	return to;
+ align:
+	rem = 4 - rem;
+	n = n - rem;
+	do {
+		*--tmp_to = *--tmp_from;
+	} while (--rem);
+	chunks = n / 8;
+	if (chunks)
+		goto copy_chunks;
+	goto lessthan8;
+}
+
+strong_alias(__memmove, memmove)