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-rw-r--r--arch/tile/lib/strchr_32.c66
1 files changed, 66 insertions, 0 deletions
diff --git a/arch/tile/lib/strchr_32.c b/arch/tile/lib/strchr_32.c
new file mode 100644
index 000000000000..c94e6f7ae7b5
--- /dev/null
+++ b/arch/tile/lib/strchr_32.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * 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, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/module.h>
+
+#undef strchr
+
+char *strchr(const char *s, int c)
+{
+ int z, g;
+
+ /* Get an aligned pointer. */
+ const uintptr_t s_int = (uintptr_t) s;
+ const uint32_t *p = (const uint32_t *)(s_int & -4);
+
+ /* Create four copies of the byte for which we are looking. */
+ const uint32_t goal = 0x01010101 * (uint8_t) c;
+
+ /* Read the first aligned word, but force bytes before the string to
+ * match neither zero nor goal (we make sure the high bit of each
+ * byte is 1, and the low 7 bits are all the opposite of the goal
+ * byte).
+ *
+ * Note that this shift count expression works because we know shift
+ * counts are taken mod 32.
+ */
+ const uint32_t before_mask = (1 << (s_int << 3)) - 1;
+ uint32_t v = (*p | before_mask) ^ (goal & __insn_shrib(before_mask, 1));
+
+ uint32_t zero_matches, goal_matches;
+ while (1) {
+ /* Look for a terminating '\0'. */
+ zero_matches = __insn_seqb(v, 0);
+
+ /* Look for the goal byte. */
+ goal_matches = __insn_seqb(v, goal);
+
+ if (__builtin_expect(zero_matches | goal_matches, 0))
+ break;
+
+ v = *++p;
+ }
+
+ z = __insn_ctz(zero_matches);
+ g = __insn_ctz(goal_matches);
+
+ /* If we found c before '\0' we got a match. Note that if c == '\0'
+ * then g == z, and we correctly return the address of the '\0'
+ * rather than NULL.
+ */
+ return (g <= z) ? ((char *)p) + (g >> 3) : NULL;
+}
+EXPORT_SYMBOL(strchr);