/*-*- 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)));
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;
}
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);
}
}