diff options
Diffstat (limited to 'ports/sysdeps/tile/tilepro/memset.c')
| -rw-r--r-- | ports/sysdeps/tile/tilepro/memset.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/ports/sysdeps/tile/tilepro/memset.c b/ports/sysdeps/tile/tilepro/memset.c new file mode 100644 index 0000000000..6fb9ab81ed --- /dev/null +++ b/ports/sysdeps/tile/tilepro/memset.c @@ -0,0 +1,151 @@ +/* Copyright (C) 2011 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011. + + 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> +#include <stdint.h> +#include <arch/chip.h> + +void * +__memset (void *s, int c, size_t n) +{ + uint32_t *out32; + int n32; + uint32_t v16, v32; + uint8_t *out8 = s; + int to_align32; + + /* Experimentation shows that a trivial tight loop is a win up until + around a size of 20, where writing a word at a time starts to win. */ +#define BYTE_CUTOFF 20 + +#if BYTE_CUTOFF < 3 + /* This must be at least at least this big, or some code later + on doesn't work. */ +# error "BYTE_CUTOFF is too small." +#endif + + if (n < BYTE_CUTOFF) + { + /* Strangely, this turns out to be the tightest way to write + this loop. */ + if (n != 0) + { + do + { + /* Strangely, combining these into one line performs worse. */ + *out8 = c; + out8++; + } + while (--n != 0); + } + + return s; + } + + /* Align 'out8'. We know n >= 3 so this won't write past the end. */ + while (((uintptr_t) out8 & 3) != 0) + { + *out8++ = c; + --n; + } + + /* Align 'n'. */ + while (n & 3) + out8[--n] = c; + + out32 = (uint32_t *) out8; + n32 = n >> 2; + + /* Tile input byte out to 32 bits. */ + v16 = __insn_intlb (c, c); + v32 = __insn_intlh (v16, v16); + + /* This must be at least 8 or the following loop doesn't work. */ +#define CACHE_LINE_SIZE_IN_WORDS (CHIP_L2_LINE_SIZE() / 4) + + /* Determine how many words we need to emit before the 'out32' + pointer becomes aligned modulo the cache line size. */ + to_align32 = (-((uintptr_t) out32 >> 2)) & (CACHE_LINE_SIZE_IN_WORDS - 1); + + /* Only bother aligning and using wh64 if there is at least one full + cache line to process. This check also prevents overrunning the + end of the buffer with alignment words. */ + if (to_align32 <= n32 - CACHE_LINE_SIZE_IN_WORDS) + { + int lines_left; + + /* Align out32 mod the cache line size so we can use wh64. */ + n32 -= to_align32; + for (; to_align32 != 0; to_align32--) + { + *out32 = v32; + out32++; + } + + /* Use unsigned divide to turn this into a right shift. */ + lines_left = (unsigned) n32 / CACHE_LINE_SIZE_IN_WORDS; + + do + { + /* Only wh64 a few lines at a time, so we don't exceed the + maximum number of victim lines. */ + int x = ((lines_left < CHIP_MAX_OUTSTANDING_VICTIMS ())? lines_left + : CHIP_MAX_OUTSTANDING_VICTIMS ()); + uint32_t *wh = out32; + int i = x; + int j; + + lines_left -= x; + + do + { + __insn_wh64 (wh); + wh += CACHE_LINE_SIZE_IN_WORDS; + } + while (--i); + + for (j = x * (CACHE_LINE_SIZE_IN_WORDS / 4); j != 0; j--) + { + *out32++ = v32; + *out32++ = v32; + *out32++ = v32; + *out32++ = v32; + } + } + while (lines_left != 0); + + /* We processed all full lines above, so only this many words + remain to be processed. */ + n32 &= CACHE_LINE_SIZE_IN_WORDS - 1; + } + + /* Now handle any leftover values. */ + if (n32 != 0) + { + do + { + *out32 = v32; + out32++; + } + while (--n32 != 0); + } + + return s; +} +weak_alias (__memset, memset) +libc_hidden_builtin_def (memset) |