1 files changed, 81 insertions, 0 deletions
diff --git a/libc/string/powerpc/memset.c b/libc/string/powerpc/memset.c
new file mode 100644
index 000000000..c5903afa6
--- /dev/null
+++ b/libc/string/powerpc/memset.c
@@ -0,0 +1,81 @@
+/*
+ * 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>
+
+static inline int expand_byte_word(int c){
+	/* this does: 
+	   c = c << 8 | c;
+	   c = c << 16 | c ;
+	*/
+	asm("rlwimi	%0,%0,8,16,23\n"
+	    "\trlwimi	%0,%0,16,0,15\n"
+	    : "=r" (c) : "0" (c));
+	return c;
+}
+void attribute_hidden *__memset(void *to, int c, size_t n)
+{
+	unsigned long rem, chunks;
+	unsigned char *tmp_to;
+
+	chunks = n / 8;
+	tmp_to = to - 4;
+	c = expand_byte_word(c);
+	if (!chunks)
+		goto lessthan8;
+	rem = (unsigned long )tmp_to % 4;
+	if (rem)
+		goto align;
+ copy_chunks:
+	do {
+		*(unsigned long *)(tmp_to+4) = c;
+		tmp_to += 4;
+		*(unsigned long *)(tmp_to+4) = c;
+		tmp_to += 4;
+	} while (--chunks);
+ lessthan8:
+	n = n % 8;
+	if (n >= 4) {
+		*(unsigned long *)(tmp_to+4) = c;
+		tmp_to += 4;
+		n = n-4;
+	}
+	if (!n ) return to;
+	tmp_to += 3;
+	do {
+		*++tmp_to = c;
+	} while (--n);
+	
+	return to;
+ align:
+	rem = 4 - rem;
+	n = n-rem;
+	do {
+		*(tmp_to+4) = c;
+		++tmp_to;
+	} while (--rem);
+	chunks = n / 8;
+	if (chunks)
+		goto copy_chunks;
+	goto lessthan8;
+}
+
+strong_alias(__memset, memset)