arch/tile: core support for Tilera 32-bit chips.

This change is the core kernel support for TILEPro and TILE64 chips.
No driver support (except the console driver) is included yet.

This includes the relevant Linux headers in asm/; the low-level
low-level "Tile architecture" headers in arch/, which are
shared with the hypervisor, etc., and are build-system agnostic;
and the relevant hypervisor headers in hv/.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Reviewed-by: Paul Mundt <lethal@linux-sh.org>

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);