aboutsummaryrefslogtreecommitdiffstats
path: root/arch/tile/lib/memchr_32.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/tile/lib/memchr_32.c')
-rw-r--r--arch/tile/lib/memchr_32.c35
1 files changed, 19 insertions, 16 deletions
diff --git a/arch/tile/lib/memchr_32.c b/arch/tile/lib/memchr_32.c
index 6235283b485..cc3d9badf03 100644
--- a/arch/tile/lib/memchr_32.c
+++ b/arch/tile/lib/memchr_32.c
@@ -18,12 +18,24 @@
18 18
19void *memchr(const void *s, int c, size_t n) 19void *memchr(const void *s, int c, size_t n)
20{ 20{
21 const uint32_t *last_word_ptr;
22 const uint32_t *p;
23 const char *last_byte_ptr;
24 uintptr_t s_int;
25 uint32_t goal, before_mask, v, bits;
26 char *ret;
27
28 if (__builtin_expect(n == 0, 0)) {
29 /* Don't dereference any memory if the array is empty. */
30 return NULL;
31 }
32
21 /* Get an aligned pointer. */ 33 /* Get an aligned pointer. */
22 const uintptr_t s_int = (uintptr_t) s; 34 s_int = (uintptr_t) s;
23 const uint32_t *p = (const uint32_t *)(s_int & -4); 35 p = (const uint32_t *)(s_int & -4);
24 36
25 /* Create four copies of the byte for which we are looking. */ 37 /* Create four copies of the byte for which we are looking. */
26 const uint32_t goal = 0x01010101 * (uint8_t) c; 38 goal = 0x01010101 * (uint8_t) c;
27 39
28 /* Read the first word, but munge it so that bytes before the array 40 /* Read the first word, but munge it so that bytes before the array
29 * will not match goal. 41 * will not match goal.
@@ -31,23 +43,14 @@ void *memchr(const void *s, int c, size_t n)
31 * Note that this shift count expression works because we know 43 * Note that this shift count expression works because we know
32 * shift counts are taken mod 32. 44 * shift counts are taken mod 32.
33 */ 45 */
34 const uint32_t before_mask = (1 << (s_int << 3)) - 1; 46 before_mask = (1 << (s_int << 3)) - 1;
35 uint32_t v = (*p | before_mask) ^ (goal & before_mask); 47 v = (*p | before_mask) ^ (goal & before_mask);
36 48
37 /* Compute the address of the last byte. */ 49 /* Compute the address of the last byte. */
38 const char *const last_byte_ptr = (const char *)s + n - 1; 50 last_byte_ptr = (const char *)s + n - 1;
39 51
40 /* Compute the address of the word containing the last byte. */ 52 /* Compute the address of the word containing the last byte. */
41 const uint32_t *const last_word_ptr = 53 last_word_ptr = (const uint32_t *)((uintptr_t) last_byte_ptr & -4);
42 (const uint32_t *)((uintptr_t) last_byte_ptr & -4);
43
44 uint32_t bits;
45 char *ret;
46
47 if (__builtin_expect(n == 0, 0)) {
48 /* Don't dereference any memory if the array is empty. */
49 return NULL;
50 }
51 54
52 while ((bits = __insn_seqb(v, goal)) == 0) { 55 while ((bits = __insn_seqb(v, goal)) == 0) {
53 if (__builtin_expect(p == last_word_ptr, 0)) { 56 if (__builtin_expect(p == last_word_ptr, 0)) {