2020-06-15 14:18:57 +00:00
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/*-*- 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 2020 Justine Alexandra Roberts Tunney │
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│ │
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2020-12-28 01:18:44 +00:00
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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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2020-06-15 14:18:57 +00:00
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│ │
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2020-12-28 01:18:44 +00:00
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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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2020-06-15 14:18:57 +00:00
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╚─────────────────────────────────────────────────────────────────────────────*/
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2020-08-25 11:23:25 +00:00
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#include "libc/intrin/psubusb.h"
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#include "libc/limits.h"
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2021-03-01 07:42:35 +00:00
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#include "libc/macros.internal.h"
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2020-06-15 14:18:57 +00:00
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#include "libc/str/str.h"
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/**
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2020-08-25 11:23:25 +00:00
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* Subtracts unsigned 8-bit integers w/ saturation.
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*
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* @param 𝑎 [w/o] receives result
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* @param 𝑏 [r/o] supplies first input vector
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* @param 𝑐 [r/o] supplies second input vector
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* @mayalias
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2020-06-15 14:18:57 +00:00
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*/
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2023-05-09 08:56:56 +00:00
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void(psubusb)(uint8_t a[16], const uint8_t b[16], const uint8_t c[16]) {
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2020-08-25 11:23:25 +00:00
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unsigned i;
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uint8_t r[16];
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for (i = 0; i < 16; ++i) {
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r[i] = MIN(UINT8_MAX, MAX(UINT8_MIN, b[i] - c[i]));
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2020-06-15 14:18:57 +00:00
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}
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2021-07-12 06:17:47 +00:00
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__builtin_memcpy(a, r, 16);
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2020-06-15 14:18:57 +00:00
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}
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