/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-â
âvi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :viâ
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â Copyright 2020 Justine Alexandra Roberts Tunney                              â
â                                                                              â
â Permission to use, copy, modify, and/or distribute this software for         â
â any purpose with or without fee is hereby granted, provided that the         â
â above copyright notice and this permission notice appear in all copies.      â
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â THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                â
â WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                â
â WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             â
â AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         â
â DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        â
â PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               â
â TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             â
â PERFORMANCE OF THIS SOFTWARE.                                                â
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#include "libc/intrin/palignr.h"
#include "libc/assert.h"
#include "libc/macros.internal.h"

/**
 * Overlaps vectors.
 *
 *     ð= 0 means ðâð
 *   0<ð<16 means ðâðâð
 *     ð=16 means ðâð
 *  16<ð<32 means ðâðâ0
 *     ðâ¥32 means ðâ0
 *
 * @param ð goes faster as constexpr
 * @note not compatible with mmx
 * @see pvalignr()
 * @mayalias
 */
void(palignr)(void *c, const void *b, const void *a, unsigned long i) {
  char t[48];
  __builtin_memcpy(t, a, 16);
  __builtin_memcpy(t + 16, b, 16);
  __builtin_memset(t + 32, 0, 16);
  __builtin_memcpy(c, t + MIN(i, 32), 16);
}
