summaryrefslogtreecommitdiff
path: root/libc/string/powerpc/string.c
diff options
context:
space:
mode:
authorEric Andersen <andersen@codepoet.org>2004-01-27 07:36:19 +0000
committerEric Andersen <andersen@codepoet.org>2004-01-27 07:36:19 +0000
commit2e6cfb475a941a7b6429c71b245f5452909437dd (patch)
tree6e633c0f8272757eec63c5c5ed35a171ba858bbf /libc/string/powerpc/string.c
parenteee979719db7ba3f014fca22d9309bd7fbad2745 (diff)
Joakim Tjernlund writes:
Hi Erik I have had some fun trying to optimize memcpy, memset and memmove for PPC. There are only boot tested, but I don't expect any problems :) Read the comments in powerpc/string.c for more info. Patch is relative to libc/string Jocke
Diffstat (limited to 'libc/string/powerpc/string.c')
-rw-r--r--libc/string/powerpc/string.c201
1 files changed, 201 insertions, 0 deletions
diff --git a/libc/string/powerpc/string.c b/libc/string/powerpc/string.c
new file mode 100644
index 000000000..32485670d
--- /dev/null
+++ b/libc/string/powerpc/string.c
@@ -0,0 +1,201 @@
+/*
+ * This program is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Library General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more
+ * details.
+ */
+
+/* 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.
+ *
+ * Copyright (C) 2004 Joakim Tjernlund
+ */
+
+#define _STDIO_UTILITY
+#define _GNU_SOURCE
+#include <string.h>
+#include <locale.h> /* for __LOCALE_C_ONLY */
+
+#ifdef L_memcpy
+void *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;
+ void *tmp_to;
+
+ chunks = n / 8;
+ 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 *)(from+4);
+ from += 8;
+ tmp2 = *(unsigned long *)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 = *++(unsigned long *)from;
+ n = n-4;
+ }
+ if (!n ) return to;
+ from += 3;
+ tmp_to += 3;
+ do {
+ *++(unsigned char *)tmp_to = *++(unsigned char *)from;
+ } while (--n);
+
+ return to;
+ align:
+ rem = 4 - rem;
+ n = n-rem;
+ do {
+ *(unsigned char *)(tmp_to+4) = *(unsigned char *)(from+4);
+ ++from;
+ ++tmp_to;
+ } while (--rem);
+ chunks = n / 8;
+ if (chunks)
+ goto copy_chunks;
+ goto lessthan8;
+}
+#endif
+
+#ifdef L_memmove
+void *memmove(void *to, const void *from, size_t n)
+{
+ unsigned long rem, chunks, tmp1, tmp2;
+ void *tmp_to;
+
+ if (from >= to)
+ return memcpy(to, from, n);
+ chunks = n / 8;
+ 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 *)(from-4);
+ from -= 8;
+ tmp2 = *(unsigned long *)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 = *--(unsigned long *)from;
+ n = n-4;
+ }
+ if (!n ) return to;
+ do {
+ *--(unsigned char *)tmp_to = *--(unsigned char *)from;
+ } while (--n);
+
+ return to;
+ align:
+ rem = 4 - rem;
+ n = n-rem;
+ do {
+ *--(unsigned char *)tmp_to = *--(unsigned char *)from;
+ } while (--rem);
+ chunks = n / 8;
+ if (chunks)
+ goto copy_chunks;
+ goto lessthan8;
+}
+#endif
+
+#ifdef L_memset
+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 *memset(void *to, int c, size_t n)
+{
+ unsigned long rem, chunks;
+ void *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 = c;
+ *++(unsigned long *)tmp_to = c;
+ } while (--chunks);
+ lessthan8:
+ n = n % 8;
+ if (n >= 4) {
+ *++(unsigned long *)tmp_to = c;
+ n = n-4;
+ }
+ if (!n ) return to;
+ tmp_to += 3;
+ do {
+ *++(unsigned char *)tmp_to = c;
+ } while (--n);
+
+ return to;
+ align:
+ rem = 4 - rem;
+ n = n-rem;
+ do {
+ *(unsigned char *)(tmp_to+4) = c;
+ ++tmp_to;
+ } while (--rem);
+ chunks = n / 8;
+ if (chunks)
+ goto copy_chunks;
+ goto lessthan8;
+}
+#endif
+
+#ifdef L_bzero
+void bzero(void *s, size_t n)
+{
+ (void)memset(s, 0, n);
+}
+#endif