| /* Copyright (C) 2011-2014 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) |