/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│ │vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│ ╞══════════════════════════════════════════════════════════════════════════════╡ │ Copyright 2021 Justine Alexandra Roberts Tunney │ │ │ │ Permission to use, copy, modify, and/or distribute this software for │ │ any purpose with or without fee is hereby granted, provided that the │ │ above copyright notice and this permission notice appear in all copies. │ │ │ │ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │ │ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │ │ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │ │ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │ │ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │ │ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │ │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │ │ PERFORMANCE OF THIS SOFTWARE. │ ╚─────────────────────────────────────────────────────────────────────────────*/ #include "libc/assert.h" #include "libc/dce.h" #include "libc/intrin/asan.internal.h" #include "libc/nexgen32e/nexgen32e.h" #include "libc/nexgen32e/x86feature.h" #include "libc/str/str.h" typedef char xmm_t __attribute__((__vector_size__(16), __aligned__(1))); typedef long long xmm_a __attribute__((__vector_size__(16), __aligned__(16))); noasan static dontinline antiquity void *memset_sse(char *p, char c, size_t n) { xmm_t v = {c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c}; if (IsAsan()) __asan_verify(p, n); if (n <= 32) { *(xmm_t *)(p + n - 16) = v; *(xmm_t *)p = v; } else { do { n -= 32; *(xmm_t *)(p + n) = v; *(xmm_t *)(p + n + 16) = v; } while (n > 32); *(xmm_t *)(p + 16) = v; *(xmm_t *)p = v; } return p; } noasan microarchitecture("avx") static void *memset_avx(char *p, char c, size_t n) { char *t; xmm_t v = {c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c}; if (IsAsan()) __asan_verify(p, n); if (n <= 32) { *(xmm_t *)(p + n - 16) = v; *(xmm_t *)p = v; } else if (n >= 1024 && X86_HAVE(ERMS)) { asm("rep stosb" : "=D"(t), "+c"(n), "=m"(*(char(*)[n])p) : "0"(p), "a"(c)); } else { if (n < kHalfCache3 || !kHalfCache3) { do { n -= 32; *(xmm_t *)(p + n) = v; *(xmm_t *)(p + n + 16) = v; } while (n > 32); } else { while ((uintptr_t)(p + n) & 15) { p[--n] = c; } do { n -= 32; __builtin_ia32_movntdq((xmm_a *)(p + n), (xmm_a)v); __builtin_ia32_movntdq((xmm_a *)(p + n + 16), (xmm_a)v); } while (n > 32); asm("sfence"); } *(xmm_t *)(p + 16) = v; *(xmm_t *)p = v; } return p; } /** * Sets memory. * * memset n=0 992 picoseconds * memset n=1 992 ps/byte 984 mb/s * memset n=2 330 ps/byte 2,952 mb/s * memset n=3 330 ps/byte 2,952 mb/s * memset n=4 165 ps/byte 5,904 mb/s * memset n=7 94 ps/byte 10,333 mb/s * memset n=8 124 ps/byte 7,872 mb/s * memset n=15 66 ps/byte 14,761 mb/s * memset n=16 62 ps/byte 15,745 mb/s * memset n=31 32 ps/byte 30,506 mb/s * memset n=32 20 ps/byte 47,236 mb/s * memset n=63 26 ps/byte 37,198 mb/s * memset n=64 20 ps/byte 47,236 mb/s * memset n=127 23 ps/byte 41,660 mb/s * memset n=128 12 ps/byte 75,578 mb/s * memset n=255 18 ps/byte 53,773 mb/s * memset n=256 12 ps/byte 75,578 mb/s * memset n=511 17 ps/byte 55,874 mb/s * memset n=512 12 ps/byte 75,578 mb/s * memset n=1023 16 ps/byte 58,080 mb/s * memset n=1024 11 ps/byte 86,375 mb/s * memset n=2047 9 ps/byte 101 gb/s * memset n=2048 8 ps/byte 107 gb/s * memset n=4095 8 ps/byte 113 gb/s * memset n=4096 8 ps/byte 114 gb/s * memset n=8191 7 ps/byte 126 gb/s * memset n=8192 7 ps/byte 126 gb/s * memset n=16383 7 ps/byte 133 gb/s * memset n=16384 7 ps/byte 131 gb/s * memset n=32767 14 ps/byte 69,246 mb/s * memset n=32768 6 ps/byte 138 gb/s * memset n=65535 15 ps/byte 62,756 mb/s * memset n=65536 15 ps/byte 62,982 mb/s * memset n=131071 18 ps/byte 52,834 mb/s * memset n=131072 15 ps/byte 62,023 mb/s * memset n=262143 15 ps/byte 61,169 mb/s * memset n=262144 16 ps/byte 61,011 mb/s * memset n=524287 16 ps/byte 60,633 mb/s * memset n=524288 16 ps/byte 57,902 mb/s * memset n=1048575 16 ps/byte 60,405 mb/s * memset n=1048576 16 ps/byte 58,754 mb/s * memset n=2097151 16 ps/byte 59,329 mb/s * memset n=2097152 16 ps/byte 58,729 mb/s * memset n=4194303 16 ps/byte 59,329 mb/s * memset n=4194304 16 ps/byte 59,262 mb/s * memset n=8388607 16 ps/byte 59,530 mb/s * memset n=8388608 16 ps/byte 60,205 mb/s * * @param p is memory address * @param c is masked with 255 and used as repeated byte * @param n is byte length * @return p * @asyncsignalsafe */ void *memset(void *p, int c, size_t n) { char *b; uint32_t u; uint64_t x; b = p; if (n <= 16) { if (n >= 8) { x = 0x0101010101010101ul * (c & 255); __builtin_memcpy(b, &x, 8); __builtin_memcpy(b + n - 8, &x, 8); } else if (n >= 4) { u = 0x01010101u * (c & 255); __builtin_memcpy(b, &u, 4); __builtin_memcpy(b + n - 4, &u, 4); } else if (n) { do { asm volatile("" ::: "memory"); b[--n] = c; } while (n); } return b; } else if (IsTiny()) { asm("rep stosb" : "+D"(b), "+c"(n), "=m"(*(char(*)[n])b) : "0"(p), "a"(c)); return p; } else if (X86_HAVE(AVX)) { return memset_avx(b, c, n); } else { return memset_sse(b, c, n); } }