cosmopolitan/libc/intrin/pslldq.c

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/*-*- 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 2020 Justine Alexandra Roberts Tunney
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "libc/intrin/pslldq.h"
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#include "libc/str/str.h"
/**
* Shifts vector right by n bytes w/ zero-fill.
*
* @param a is input vector
* @param b receives output
* @mayalias
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*/
void(pslldq)(uint8_t b[16], const uint8_t a[16], unsigned long n) {
unsigned i;
if (n > 16) n = 16;
memmove(b + n, a, 16 - n);
memset(b, 0, n);
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}