diff options
Diffstat (limited to 'ports/sysdeps/tile/tilegx/memset.c')
| -rw-r--r-- | ports/sysdeps/tile/tilegx/memset.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/ports/sysdeps/tile/tilegx/memset.c b/ports/sysdeps/tile/tilegx/memset.c new file mode 100644 index 0000000000..dad3eadc5a --- /dev/null +++ b/ports/sysdeps/tile/tilegx/memset.c @@ -0,0 +1,151 @@ +/* Copyright (C) 2011-2012 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 <arch/chip.h> +#include <string.h> +#include <stdint.h> +#include "string-endian.h" + +void * +__memset (void *s, int c, size_t n) +{ + uint64_t *out64; + int n64, to_align64; + uint64_t v64; + uint8_t *out8 = s; + + /* 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 < 7 + /* 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 >= 7 so this won't write past the end. */ + while (((uintptr_t) out8 & 7) != 0) + { + *out8++ = c; + --n; + } + + /* Align 'n'. */ + while (n & 7) + out8[--n] = c; + + out64 = (uint64_t *) out8; + n64 = n >> 3; + + /* Tile input byte out to 64 bits. */ + v64 = copy_byte(c); + + /* This must be at least 8 or the following loop doesn't work. */ +#define CACHE_LINE_SIZE_IN_DOUBLEWORDS (CHIP_L2_LINE_SIZE() / 8) + + /* Determine how many words we need to emit before the 'out32' + pointer becomes aligned modulo the cache line size. */ + to_align64 = (-((uintptr_t) out64 >> 3)) & + (CACHE_LINE_SIZE_IN_DOUBLEWORDS - 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_align64 <= n64 - CACHE_LINE_SIZE_IN_DOUBLEWORDS) + { + int lines_left; + + /* Align out64 mod the cache line size so we can use wh64. */ + n64 -= to_align64; + for (; to_align64 != 0; to_align64--) + { + *out64 = v64; + out64++; + } + + /* Use unsigned divide to turn this into a right shift. */ + lines_left = (unsigned) n64 / CACHE_LINE_SIZE_IN_DOUBLEWORDS; + + 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 ()); + uint64_t *wh = out64; + int i = x; + int j; + + lines_left -= x; + + do + { + __insn_wh64 (wh); + wh += CACHE_LINE_SIZE_IN_DOUBLEWORDS; + } + while (--i); + + for (j = x * (CACHE_LINE_SIZE_IN_DOUBLEWORDS / 4); j != 0; j--) + { + *out64++ = v64; + *out64++ = v64; + *out64++ = v64; + *out64++ = v64; + } + } + while (lines_left != 0); + + /* We processed all full lines above, so only this many + words remain to be processed. */ + n64 &= CACHE_LINE_SIZE_IN_DOUBLEWORDS - 1; + } + + /* Now handle any leftover values. */ + if (n64 != 0) + { + do + { + *out64 = v64; + out64++; + } + while (--n64 != 0); + } + + return s; +} +weak_alias (__memset, memset) +libc_hidden_builtin_def (memset) |