mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-07-12 14:09:12 +00:00
Make numerous improvements
- Python static hello world now 1.8mb
- Python static fully loaded now 10mb
- Python HTTPS client now uses MbedTLS
- Python REPL now completes import stmts
- Increase stack size for Python for now
- Begin synthesizing posixpath and ntpath
- Restore Python \N{UNICODE NAME} support
- Restore Python NFKD symbol normalization
- Add optimized code path for Intel SHA-NI
- Get more Python unit tests passing faster
- Get Python help() pagination working on NT
- Python hashlib now supports MbedTLS PBKDF2
- Make memcpy/memmove/memcmp/bcmp/etc. faster
- Add Mersenne Twister and Vigna to LIBC_RAND
- Provide privileged __printf() for error code
- Fix zipos opendir() so that it reports ENOTDIR
- Add basic chmod() implementation for Windows NT
- Add Cosmo's best functions to Python cosmo module
- Pin function trace indent depth to that of caller
- Show memory diagram on invalid access in MODE=dbg
- Differentiate stack overflow on crash in MODE=dbg
- Add stb_truetype and tools for analyzing font files
- Upgrade to UNICODE 13 and reduce its binary footprint
- COMPILE.COM now logs resource usage of build commands
- Start implementing basic poll() support on bare metal
- Set getauxval(AT_EXECFN) to GetModuleFileName() on NT
- Add descriptions to strerror() in non-TINY build modes
- Add COUNTBRANCH() macro to help with micro-optimizations
- Make error / backtrace / asan / memory code more unbreakable
- Add fast perfect C implementation of μ-Law and a-Law audio codecs
- Make strtol() functions consistent with other libc implementations
- Improve Linenoise implementation (see also github.com/jart/bestline)
- COMPILE.COM now suppresses stdout/stderr of successful build commands
This commit is contained in:
Justine Tunney
parent
fa7b4f5bd1
commit
39bf41f4eb
806 changed files with 77494 additions and 63859 deletions
154
libc/str/timingsafe_bcmp.c
Normal file
154
libc/str/timingsafe_bcmp.c
Normal file
|
|
@ -0,0 +1,154 @@
|
|||
/*-*- 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/bits/likely.h"
|
||||
#include "libc/dce.h"
|
||||
#include "libc/nexgen32e/x86feature.h"
|
||||
#include "libc/str/str.h"
|
||||
|
||||
typedef uint64_t xmm_t __attribute__((__vector_size__(16), __aligned__(1)));
|
||||
|
||||
static noinline antiquity unsigned timingsafe_bcmp_sse(const char *p,
|
||||
const char *q,
|
||||
size_t n) {
|
||||
uint64_t w;
|
||||
xmm_t a = {0};
|
||||
while (n > 16 + 16) {
|
||||
a |= *(const xmm_t *)p ^ *(const xmm_t *)q;
|
||||
p += 16;
|
||||
q += 16;
|
||||
n -= 16;
|
||||
}
|
||||
a |= *(const xmm_t *)p ^ *(const xmm_t *)q;
|
||||
a |= *(const xmm_t *)(p + n - 16) ^ *(const xmm_t *)(q + n - 16);
|
||||
w = a[0] | a[1];
|
||||
return w | w >> 32;
|
||||
}
|
||||
|
||||
microarchitecture("avx") static int timingsafe_bcmp_avx(const char *p,
|
||||
const char *q,
|
||||
size_t n) {
|
||||
uint64_t w;
|
||||
xmm_t a = {0};
|
||||
if (n > 32) {
|
||||
if (n >= 16 + 64) {
|
||||
xmm_t b = {0};
|
||||
xmm_t c = {0};
|
||||
xmm_t d = {0};
|
||||
do {
|
||||
a |= ((const xmm_t *)p)[0] ^ ((const xmm_t *)q)[0];
|
||||
b |= ((const xmm_t *)p)[1] ^ ((const xmm_t *)q)[1];
|
||||
c |= ((const xmm_t *)p)[2] ^ ((const xmm_t *)q)[2];
|
||||
d |= ((const xmm_t *)p)[3] ^ ((const xmm_t *)q)[3];
|
||||
p += 64;
|
||||
q += 64;
|
||||
n -= 64;
|
||||
} while (n >= 16 + 64);
|
||||
a = a | b | c | d;
|
||||
}
|
||||
while (n > 32) {
|
||||
a |= *(const xmm_t *)p ^ *(const xmm_t *)q;
|
||||
p += 16;
|
||||
q += 16;
|
||||
n -= 16;
|
||||
}
|
||||
}
|
||||
a |= *(const xmm_t *)p ^ *(const xmm_t *)q;
|
||||
a |= *(const xmm_t *)(p + n - 16) ^ *(const xmm_t *)(q + n - 16);
|
||||
w = a[0] | a[1];
|
||||
return w | w >> 32;
|
||||
}
|
||||
|
||||
/**
|
||||
* Tests inequality of first 𝑛 bytes of 𝑝 and 𝑞.
|
||||
*
|
||||
* The following expression:
|
||||
*
|
||||
* !!timingsafe_bcmp(p, q, n)
|
||||
*
|
||||
* Is functionally equivalent to:
|
||||
*
|
||||
* !!memcmp(p, q, n)
|
||||
*
|
||||
* This function is faster than memcmp() and bcmp() when byte sequences
|
||||
* are assumed to always be the same; that makes it best for assertions
|
||||
* or hash table lookups, assuming 𝑛 is variable (since no gcc builtin)
|
||||
*
|
||||
* timingsafe_bcmp n=0 992 picoseconds
|
||||
* timingsafe_bcmp n=1 1 ns/byte 738 mb/s
|
||||
* timingsafe_bcmp n=2 826 ps/byte 1,181 mb/s
|
||||
* timingsafe_bcmp n=3 661 ps/byte 1,476 mb/s
|
||||
* timingsafe_bcmp n=4 330 ps/byte 2,952 mb/s
|
||||
* timingsafe_bcmp n=5 264 ps/byte 3,690 mb/s
|
||||
* timingsafe_bcmp n=6 220 ps/byte 4,428 mb/s
|
||||
* timingsafe_bcmp n=7 189 ps/byte 5,166 mb/s
|
||||
* timingsafe_bcmp n=8 124 ps/byte 7,873 mb/s
|
||||
* timingsafe_bcmp n=9 147 ps/byte 6,643 mb/s
|
||||
* timingsafe_bcmp n=15 88 ps/byte 11,072 mb/s
|
||||
* timingsafe_bcmp n=16 62 ps/byte 15,746 mb/s
|
||||
* timingsafe_bcmp n=17 136 ps/byte 7,170 mb/s
|
||||
* timingsafe_bcmp n=31 74 ps/byte 13,075 mb/s
|
||||
* timingsafe_bcmp n=32 72 ps/byte 13,497 mb/s
|
||||
* timingsafe_bcmp n=33 80 ps/byte 12,179 mb/s
|
||||
* timingsafe_bcmp n=80 57 ps/byte 16,871 mb/s
|
||||
* timingsafe_bcmp n=128 49 ps/byte 19,890 mb/s
|
||||
* timingsafe_bcmp n=256 31 ps/byte 31,493 mb/s
|
||||
* timingsafe_bcmp n=16384 14 ps/byte 67,941 mb/s
|
||||
* timingsafe_bcmp n=32768 29 ps/byte 33,121 mb/s
|
||||
* timingsafe_bcmp n=131072 29 ps/byte 32,949 mb/s
|
||||
*
|
||||
* Running time is independent of the byte sequences compared, making
|
||||
* this safe to use for comparing secret values such as cryptographic
|
||||
* MACs. In contrast, memcmp() may short-circuit after finding the first
|
||||
* differing byte.
|
||||
*
|
||||
* @return nonzero if unequal, otherwise zero
|
||||
* @see timingsafe_memcmp()
|
||||
* @asyncsignalsafe
|
||||
*/
|
||||
int timingsafe_bcmp(const void *a, const void *b, size_t n) {
|
||||
const char *p = a, *q = b;
|
||||
uint32_t u, u0, u1, u2, u3;
|
||||
uint64_t w, w0, w1, w2, w3;
|
||||
if (!IsTiny()) {
|
||||
if (n >= 8) {
|
||||
if (n <= 16) {
|
||||
__builtin_memcpy(&w0, p, 8);
|
||||
__builtin_memcpy(&w1, q, 8);
|
||||
__builtin_memcpy(&w2, p + n - 8, 8);
|
||||
__builtin_memcpy(&w3, q + n - 8, 8);
|
||||
w = (w0 ^ w1) | (w2 ^ w3);
|
||||
return w | w >> 32;
|
||||
} else if (X86_HAVE(AVX)) {
|
||||
return timingsafe_bcmp_avx(p, q, n);
|
||||
} else {
|
||||
return timingsafe_bcmp_sse(p, q, n);
|
||||
}
|
||||
} else if (n >= 4) {
|
||||
__builtin_memcpy(&u0, p, 4);
|
||||
__builtin_memcpy(&u1, q, 4);
|
||||
__builtin_memcpy(&u2, p + n - 4, 4);
|
||||
__builtin_memcpy(&u3, q + n - 4, 4);
|
||||
return (u0 ^ u1) | (u2 ^ u3);
|
||||
}
|
||||
}
|
||||
for (u = 0; n--;) {
|
||||
u |= p[n] ^ q[n];
|
||||
}
|
||||
return u;
|
||||
}
|
||||
Loading…
Add table
Add a link
Reference in a new issue