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https://github.com/jart/cosmopolitan.git
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55 lines
2.7 KiB
C
55 lines
2.7 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 "third_party/mbedtls/bignum_internal.h"
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#include "third_party/mbedtls/platform.h"
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#ifdef __x86_64__
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typedef uint64_t xmm_t __attribute__((__vector_size__(16), __aligned__(1)));
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void ShiftRightAvx(uint64_t *p, size_t n, unsigned char k) {
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uint64_t p1;
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xmm_t cv = {0};
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xmm_t i0, i1, i2, i3;
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xmm_t o0, o1, o2, o3;
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MBEDTLS_ASSERT(!(k & ~63));
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p1 = n > 1 ? p[1] : 0;
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while (n >= 4) {
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n -= 4;
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i0 = *(xmm_t *)(p + n + 2);
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i1 = *(xmm_t *)(p + n + 0);
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o0 = i0 >> k | (xmm_t){i0[1], cv[0]} << (64 - k);
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o1 = i1 >> k | (xmm_t){i1[1], i0[0]} << (64 - k);
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cv = i1;
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*(xmm_t *)(p + n + 2) = o0;
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*(xmm_t *)(p + n + 0) = o1;
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}
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if (n >= 2) {
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n -= 2;
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i0 = *(xmm_t *)(p + n);
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o0 = i0 >> k | (xmm_t){i0[1], cv[0]} << (64 - k);
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cv = i0;
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*(xmm_t *)(p + n) = o0;
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}
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if (n) {
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p[0] = p[0] >> k | p1 << (64 - k);
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}
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}
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#endif /* __x86_64__ */
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