llvm-project/compiler-rt/lib/builtins/bswapdi2.c

/* ===-- bswapdi2.c - Implement __bswapdi2 ---------------------------------===
 *
 * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 * See https://llvm.org/LICENSE.txt for license information.
 * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 *
 * ===----------------------------------------------------------------------===
 *
 * This file implements __bswapdi2 for the compiler_rt library.
 *
 * ===----------------------------------------------------------------------===
 */

#include "int_lib.h"

COMPILER_RT_ABI uint64_t __bswapdi2(uint64_t u) {
  return (
      (((u)&0xff00000000000000ULL) >> 56) |
      (((u)&0x00ff000000000000ULL) >> 40) |
      (((u)&0x0000ff0000000000ULL) >> 24) |
      (((u)&0x000000ff00000000ULL) >> 8)  |
      (((u)&0x00000000ff000000ULL) << 8)  |
      (((u)&0x0000000000ff0000ULL) << 24) |
      (((u)&0x000000000000ff00ULL) << 40) |
      (((u)&0x00000000000000ffULL) << 56));
}