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-rw-r--r--libc/string/powerpc/memcpy.c80
1 files changed, 80 insertions, 0 deletions
diff --git a/libc/string/powerpc/memcpy.c b/libc/string/powerpc/memcpy.c
new file mode 100644
index 000000000..e731f3578
--- /dev/null
+++ b/libc/string/powerpc/memcpy.c
@@ -0,0 +1,80 @@
+/*
+ * 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 *__memcpy(void *to, const void *from, size_t n)
+/* PPC can do pre increment and load/store, but not post increment and load/store.
+ Therefore use *++ptr instead of *ptr++. */
+{
+ unsigned long rem, chunks, tmp1, tmp2;
+ unsigned char *tmp_to;
+ unsigned char *tmp_from = (unsigned char *)from;
+
+ chunks = n / 8;
+ tmp_from -= 4;
+ tmp_to = to - 4;
+ 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;
+ tmp_from += 3;
+ tmp_to += 3;
+ do {
+ *++tmp_to = *++tmp_from;
+ } while (--n);
+
+ return to;
+ align:
+ rem = 4 - rem;
+ n = n - rem;
+ do {
+ *(tmp_to+4) = *(tmp_from+4);
+ ++tmp_from;
+ ++tmp_to;
+ } while (--rem);
+ chunks = n / 8;
+ if (chunks)
+ goto copy_chunks;
+ goto lessthan8;
+}
+
+strong_alias(__memcpy, memcpy)