/*-*- 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
â                                                                              â
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
ââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââ*/
#include "libc/intrin/bsr.h"

/**
 * Returns binary logarithm of ð¥.
 *
 *                           ctz(ð¥)         31^clz(ð¥)   clz(ð¥)
 *       uint32 ð¥  _bsf(ð¥) tzcnt(ð¥)   ffs(ð¥)  _bsr(ð¥) lzcnt(ð¥)
 *     0x00000000      wut       32        0      wut       32
 *     0x00000001        0        0        1        0       31
 *     0x80000001        0        0        1       31        0
 *     0x80000000       31       31       32       31        0
 *     0x00000010        4        4        5        4       27
 *     0x08000010        4        4        5       27        4
 *     0x08000000       27       27       28       27        4
 *     0xffffffff        0        0        1       31        0
 *
 * @param x is a 32-bit integer
 * @return number in range 0..31 or undefined if ð¥ is 0
 */
int(_bsr)(int x) {
  return _bsr(x);
}

/**
 * Returns binary logarithm of ð¥.
 *
 *                           ctz(ð¥)         31^clz(ð¥)   clz(ð¥)
 *       uint32 ð¥  _bsf(ð¥) tzcnt(ð¥)   ffs(ð¥)  _bsr(ð¥) lzcnt(ð¥)
 *     0x00000000      wut       32        0      wut       32
 *     0x00000001        0        0        1        0       31
 *     0x80000001        0        0        1       31        0
 *     0x80000000       31       31       32       31        0
 *     0x00000010        4        4        5        4       27
 *     0x08000010        4        4        5       27        4
 *     0x08000000       27       27       28       27        4
 *     0xffffffff        0        0        1       31        0
 *
 * @param x is a 64-bit integer
 * @return number in range 0..63 or undefined if ð¥ is 0
 */
int(_bsrl)(long x) {
  return _bsrl(x);
}

/**
 * Returns binary logarithm of ð¥.
 *
 *                           ctz(ð¥)         31^clz(ð¥)   clz(ð¥)
 *       uint32 ð¥  _bsf(ð¥) tzcnt(ð¥)   ffs(ð¥)  _bsr(ð¥) lzcnt(ð¥)
 *     0x00000000      wut       32        0      wut       32
 *     0x00000001        0        0        1        0       31
 *     0x80000001        0        0        1       31        0
 *     0x80000000       31       31       32       31        0
 *     0x00000010        4        4        5        4       27
 *     0x08000010        4        4        5       27        4
 *     0x08000000       27       27       28       27        4
 *     0xffffffff        0        0        1       31        0
 *
 * @param x is a 64-bit integer
 * @return number in range 0..63 or undefined if ð¥ is 0
 */
int(_bsrll)(long long x) {
  return _bsrll(x);
}
