diff options
Diffstat (limited to 'ports/sysdeps/alpha/memchr.c')
| -rw-r--r-- | ports/sysdeps/alpha/memchr.c | 174 |
1 files changed, 0 insertions, 174 deletions
diff --git a/ports/sysdeps/alpha/memchr.c b/ports/sysdeps/alpha/memchr.c deleted file mode 100644 index 6d80690..0000000 --- a/ports/sysdeps/alpha/memchr.c +++ /dev/null @@ -1,174 +0,0 @@ -/* Copyright (C) 2010-2014 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library 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 - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library. If not, see - <http://www.gnu.org/licenses/>. */ - -#include <string.h> - -typedef unsigned long word; - -static inline word -ldq_u(const void *s) -{ - return *(const word *)((word)s & -8); -} - -#define unlikely(X) __builtin_expect ((X), 0) -#define prefetch(X) __builtin_prefetch ((void *)(X), 0) - -#define cmpbeq0(X) __builtin_alpha_cmpbge(0, (X)) -#define find(X, Y) cmpbeq0 ((X) ^ (Y)) - -/* Search no more than N bytes of S for C. */ - -void * -__memchr (const void *s, int xc, size_t n) -{ - const word *s_align; - word t, current, found, mask, offset; - - if (unlikely (n == 0)) - return 0; - - current = ldq_u (s); - - /* Replicate low byte of XC into all bytes of C. */ - t = xc & 0xff; /* 0000000c */ - t = (t << 8) | t; /* 000000cc */ - t = (t << 16) | t; /* 0000cccc */ - const word c = (t << 32) | t; /* cccccccc */ - - /* Align the source, and decrement the count by the number - of bytes searched in the first word. */ - s_align = (const word *)((word)s & -8); - n += ((word)s & 7); - - /* Deal with misalignment in the first word for the comparison. */ - mask = (1ul << ((word)s & 7)) - 1; - - /* If the entire string fits within one word, we may need masking - at both the front and the back of the string. */ - if (unlikely (n <= 8)) - { - mask |= -1ul << n; - goto last_quad; - } - - found = find (current, c) & ~mask; - if (unlikely (found)) - goto found_it; - - s_align++; - n -= 8; - - /* If the block is sufficiently large, align to cacheline and prefetch. */ - if (unlikely (n >= 256)) - { - /* Prefetch 3 cache lines beyond the one we're working on. */ - prefetch (s_align + 8); - prefetch (s_align + 16); - prefetch (s_align + 24); - - while ((word)s_align & 63) - { - current = *s_align; - found = find (current, c); - if (found) - goto found_it; - s_align++; - n -= 8; - } - - /* Within each cacheline, advance the load for the next word - before the test for the previous word is complete. This - allows us to hide the 3 cycle L1 cache load latency. We - only perform this advance load within a cacheline to prevent - reading across page boundary. */ -#define CACHELINE_LOOP \ - do { \ - word i, next = s_align[0]; \ - for (i = 0; i < 7; ++i) \ - { \ - current = next; \ - next = s_align[1]; \ - found = find (current, c); \ - if (unlikely (found)) \ - goto found_it; \ - s_align++; \ - } \ - current = next; \ - found = find (current, c); \ - if (unlikely (found)) \ - goto found_it; \ - s_align++; \ - n -= 64; \ - } while (0) - - /* While there's still lots more data to potentially be read, - continue issuing prefetches for the 4th cacheline out. */ - while (n >= 256) - { - prefetch (s_align + 24); - CACHELINE_LOOP; - } - - /* Up to 3 cache lines remaining. Continue issuing advanced - loads, but stop prefetching. */ - while (n >= 64) - CACHELINE_LOOP; - - /* We may have exhausted the buffer. */ - if (n == 0) - return NULL; - } - - /* Quadword aligned loop. */ - current = *s_align; - while (n > 8) - { - found = find (current, c); - if (unlikely (found)) - goto found_it; - current = *++s_align; - n -= 8; - } - - /* The last word may need masking at the tail of the compare. */ - mask = -1ul << n; - last_quad: - found = find (current, c) & ~mask; - if (found == 0) - return NULL; - - found_it: -#ifdef __alpha_cix__ - offset = __builtin_alpha_cttz (found); -#else - /* Extract LSB. */ - found &= -found; - - /* Binary search for the LSB. */ - offset = (found & 0x0f ? 0 : 4); - offset += (found & 0x33 ? 0 : 2); - offset += (found & 0x55 ? 0 : 1); -#endif - - return (void *)((word)s_align + offset); -} - -#ifdef weak_alias -weak_alias (__memchr, memchr) -#endif -libc_hidden_builtin_def (memchr) |