Add libc optimizations to bionic for MIPS
Test: Used bionic tests available under bionic/tests folder.
Tested for mips32r1/mips32r2/mips64r6 on emulators.
Change-Id: I589415ddc496df3f6067ae34cb33ca58b3a1f276
Signed-off-by: Prashant Patil <prashant.patil@imgtec.com>
diff --git a/libc/arch-mips/string/strnlen.c b/libc/arch-mips/string/strnlen.c
new file mode 100644
index 0000000..2011deb
--- /dev/null
+++ b/libc/arch-mips/string/strnlen.c
@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) 2017 Imagination Technologies.
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with
+ * the distribution.
+ * * Neither the name of Imagination Technologies nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <string.h>
+
+#define op_t unsigned long int
+#define op_size sizeof (op_t)
+
+#if __mips64 || __mips_isa_rev >= 2
+static inline size_t __attribute__ ((always_inline))
+do_bytes (const char *base, const char *p, op_t inval)
+{
+ op_t outval = 0;
+#if __mips64
+ __asm__ volatile (
+ "dsbh %1, %0 \n\t"
+ "dshd %0, %1 \n\t"
+ "dclz %1, %0 \n\t"
+ : "+r" (inval), "+r" (outval)
+ );
+#else
+ __asm__ volatile (
+ "wsbh %1, %0 \n\t"
+ "rotr %0, %1, 16 \n\t"
+ "clz %1, %0 \n\t"
+ : "+r" (inval), "+r" (outval)
+ );
+#endif
+ p += (outval >> 3);
+ return (size_t) (p - base);
+}
+
+#define DO_WORD(in, val) { \
+ op_t tmp = ((val - mask_1) & ~val) & mask_128; \
+ if (tmp) \
+ return do_bytes(str, (const char *)(in), tmp); \
+}
+#else
+static inline size_t __attribute__ ((always_inline))
+do_bytes (const char *base, const char *p)
+{
+ for (; *p; ++p);
+ return (size_t) (p - base);
+}
+
+#define DO_WORD(in, val) { \
+ if (((val - mask_1) & ~val) & mask_128) { \
+ return do_bytes(str, (const char *)(in)); \
+ } \
+}
+#endif
+
+size_t strnlen (const char *str, size_t n) {
+ if (n != 0) {
+ const char *p = (const char *) str;
+ const op_t *w;
+ op_t mask_1, mask_128;
+
+ for (; n > 0 && ((size_t) p % op_size) != 0; --n, ++p) {
+ if (!(*p))
+ return (p - str);
+ }
+
+ w = (const op_t *) p;
+
+ __asm__ volatile (
+ "li %0, 0x01010101 \n\t"
+ : "=r" (mask_1)
+ );
+#if __mips64
+ mask_1 |= mask_1 << 32;
+#endif
+ mask_128 = mask_1 << 7;
+
+ /*
+ * Check op_size byteswize after initial alignment
+ */
+ while (n >= 4 * op_size) {
+ const op_t w0 = w[0];
+ const op_t w1 = w[1];
+ const op_t w2 = w[2];
+ const op_t w3 = w[3];
+ DO_WORD(w + 0, w0)
+ DO_WORD(w + 1, w1)
+ DO_WORD(w + 2, w2)
+ DO_WORD(w + 3, w3)
+ w += 4;
+ n -= 4 * op_size;
+ }
+
+ while (n >= op_size) {
+ DO_WORD(w, w[0]);
+ w++;
+ n -= op_size;
+ }
+
+ /*
+ * Check bytewize for remaining bytes
+ */
+ p = (const char *) w;
+ for (; n > 0; --n, ++p) {
+ if (!(*p))
+ return (p - str);
+ }
+
+ return (p - str);
+ }
+
+ return 0;
+}