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1//
2// byteswap.cpp
3//
4// Copyright (c) Microsoft Corporation. All rights reserved.
5//
6// Defines functions that swap the bytes of an unsigned integer.
7//
8#include <stdlib.h>
9
10
11
12#pragma function(_byteswap_ulong, _byteswap_uint64, _byteswap_ushort)
13
14/***
15*unsigned long _byteswap_ulong(i) - long byteswap
16*
17*Purpose:
18* Performs a byte swap on an unsigned integer.
19*
20*Entry:
21* unsigned long i: value to swap
22*
23*Exit:
24* returns swaped
25*
26*Exceptions:
27* None.
28*
29*******************************************************************************/
30
31extern "C" unsigned long __cdecl _byteswap_ulong(unsigned long const i)
32{
33 unsigned int j;
34 j = (i << 24);
35 j += (i << 8) & 0x00FF0000;
36 j += (i >> 8) & 0x0000FF00;
37 j += (i >> 24);
38 return j;
39}
40
41extern "C" unsigned short __cdecl _byteswap_ushort(unsigned short const i)
42{
43 unsigned short j;
44 j = (i << 8);
45 j += (i >> 8);
46 return j;
47}
48
49extern "C" unsigned __int64 __cdecl _byteswap_uint64(unsigned __int64 const i)
50{
51 unsigned __int64 j;
52 j = (i << 56);
53 j += (i << 40) & 0x00FF000000000000;
54 j += (i << 24) & 0x0000FF0000000000;
55 j += (i << 8) & 0x000000FF00000000;
56 j += (i >> 8) & 0x00000000FF000000;
57 j += (i >> 24) & 0x0000000000FF0000;
58 j += (i >> 40) & 0x000000000000FF00;
59 j += (i >> 56);
60 return j;
61
62}