mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 03:27:39 +00:00
d5910e2673
- Fixed bug where stdio eof wasn't being sticky - Fixed bug where fseeko() wasn't clearing eof state - Removed assert() usage from libc favoring _unassert() / _npassert()
144 lines
5.5 KiB
C
144 lines
5.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2021 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/runtime/runtime.h"
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#include "libc/str/str.h"
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#include "third_party/mbedtls/bignum_internal.h"
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#include "third_party/mbedtls/platform.h"
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forceinline int Cmp(uint64_t *a, uint64_t *b, size_t n) {
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size_t i;
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uint64_t x, y;
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while (n--) {
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x = a[n];
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y = b[n];
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if (x != y) {
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return x > y ? 1 : -1;
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}
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}
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return 0;
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}
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forceinline bool Sub(uint64_t *C, uint64_t *A, uint64_t *B, size_t n) {
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bool cf;
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uint64_t c, i;
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asm volatile("xor\t%1,%1\n\t"
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".align\t16\n1:\t"
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"mov\t(%5,%3,8),%1\n\t"
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"sbb\t(%6,%3,8),%1\n\t"
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"mov\t%1,(%4,%3,8)\n\t"
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"lea\t1(%3),%3\n\t"
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"dec\t%2\n\t"
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"jnz\t1b"
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: "=@ccb"(cf), "=&r"(c), "+c"(n), "=r"(i)
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: "r"(C), "r"(A), "r"(B), "3"(0)
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: "cc", "memory");
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return cf;
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}
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forceinline bool Add(uint64_t *C, uint64_t *A, uint64_t *B, size_t n) {
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bool cf;
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uint64_t c, i;
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asm volatile("xor\t%1,%1\n\t"
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".align\t16\n1:\t"
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"mov\t(%5,%3,8),%1\n\t"
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"adc\t(%6,%3,8),%1\n\t"
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"mov\t%1,(%4,%3,8)\n\t"
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"lea\t1(%3),%3\n\t"
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"dec\t%2\n\t"
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"jnz\t1b"
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: "=@ccc"(cf), "=&r"(c), "+c"(n), "=r"(i)
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: "r"(C), "r"(A), "r"(B), "3"(0)
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: "cc", "memory");
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return cf;
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}
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/**
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* Multiplies huge numbers faster.
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*
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* For 4096 bit numbers it's twice as fast.
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* For 16384 bit numbers it's thrice as fast.
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*/
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void Karatsuba(uint64_t *C, uint64_t *A, uint64_t *B, size_t n, uint64_t *K) {
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int q, r;
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size_t i;
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uint64_t c, t;
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uint64_t *x, *y;
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if (n == 8) {
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Mul8x8Adx(C, A, B);
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return;
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}
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switch (Cmp(A, A + n / 2, n / 2) * 3 + Cmp(B + n / 2, B, n / 2)) {
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case -1 * 3 + +0:
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case +0 * 3 + -1:
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case +0 * 3 + +0:
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case +0 * 3 + +1:
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case +1 * 3 + +0:
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Karatsuba(C, A, B, n / 2, K + n * 2);
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Karatsuba(C + n, A + n / 2, B + n / 2, n / 2, K + n * 2);
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c = Add(K, C, C + n, n);
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c += Add(C + n / 2, C + n / 2, K, n);
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break;
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case -1 * 3 + -1:
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Sub(K, A + n / 2, A, n / 2);
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Sub(K + n / 2, B, B + n / 2, n / 2);
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Karatsuba(K + n, K, K + n / 2, n / 2, K + n * 2);
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Karatsuba(C, A, B, n / 2, K + n * 2);
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Karatsuba(C + n, A + n / 2, B + n / 2, n / 2, K + n * 2);
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c = Add(K, C, C + n, n);
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c += Add(K + n, K, K + n, n);
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c += Add(C + n / 2, C + n / 2, K + n, n);
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break;
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case -1 * 3 + +1:
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Sub(K, A + n / 2, A, n / 2);
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Sub(K + n / 2, B + n / 2, B, n / 2);
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Karatsuba(K + n, K, K + n / 2, n / 2, K + n * 2);
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Karatsuba(C, A, B, n / 2, K + n * 2);
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Karatsuba(C + n, A + n / 2, B + n / 2, n / 2, K + n * 2);
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c = Add(K, C, C + n, n);
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c -= Sub(K + n, K, K + n, n);
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c += Add(C + n / 2, C + n / 2, K + n, n);
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break;
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case +1 * 3 + -1:
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Sub(K, A, A + n / 2, n / 2);
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Sub(K + n / 2, B, B + n / 2, n / 2);
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Karatsuba(K + n, K, K + n / 2, n / 2, K + n * 2);
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Karatsuba(C, A, B, n / 2, K + n * 2);
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Karatsuba(C + n, A + n / 2, B + n / 2, n / 2, K + n * 2);
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c = Add(K, C, C + n, n);
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c -= Sub(K + n, K, K + n, n);
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c += Add(C + n / 2, C + n / 2, K + n, n);
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break;
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case +1 * 3 + +1:
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Sub(K, A, A + n / 2, n / 2);
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Sub(K + n / 2, B + n / 2, B, n / 2);
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Karatsuba(K + n, K, K + n / 2, n / 2, K + n * 2);
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Karatsuba(C, A, B, n / 2, K + n * 2);
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Karatsuba(C + n, A + n / 2, B + n / 2, n / 2, K + n * 2);
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c = Add(K, C, C + n, n);
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c += Add(K + n, K, K + n, n);
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c += Add(C + n / 2, C + n / 2, K + n, n);
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break;
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default:
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unreachable;
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}
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for (i = n / 2 + n; c && i < n + n; i++) {
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t = C[i];
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c = (C[i] = t + c) < t;
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}
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}
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