Source code of Windows XP (NT5)
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/***
*rotl.c - rotate an unsigned integer left
*
* Copyright (c) 1989-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines _rotl() - performs a rotate left on an unsigned integer.
*
*Revision History:
* 06-02-89 PHG Module created
* 11-03-89 JCR Added _lrotl
* 03-15-90 GJF Made calling type _CALLTYPE1, added #include
* <cruntime.h> and fixed the copyright. Also, cleaned
* up the formatting a bit.
* 10-04-90 GJF New-style function declarators.
* 04-01-91 SRW Enable #pragma function for i386 _WIN32_ builds too.
* 09-02-92 GJF Don't build for POSIX.
* 04-06-93 SKS Replace _CRTAPI* with __cdecl
* No _CRTIMP for CRT DLL model due to intrinsic
* 12-03-93 GJF Turn on #pragma function for all MS front-ends (esp.,
* Alpha compiler).
* 01-04-01 GB Rewrote rotl functions and added __int64 version.
*
*******************************************************************************/
#ifndef _POSIX_
#include <cruntime.h>
#include <stdlib.h>
#include <limits.h>
#ifdef _MSC_VER
#pragma function(_lrotl,_rotl, _rotl64)
#endif
#if UINT_MAX != 0xffffffff /*IFSTRIP=IGN*/
#error This module assumes 32-bit integers
#endif
#if UINT_MAX != ULONG_MAX /*IFSTRIP=IGN*/
#error This module assumes sizeof(int) == sizeof(long)
#endif
/***
*unsigned _rotl(val, shift) - int rotate left
*
*Purpose:
* Performs a rotate left on an unsigned integer.
*
* [Note: The _lrotl entry is based on the assumption
* that sizeof(int) == sizeof(long).]
*Entry:
* unsigned val: value to rotate
* int shift: number of bits to shift by
*
*Exit:
* returns rotated value
*
*Exceptions:
* None.
*
*******************************************************************************/
unsigned long __cdecl _lrotl (
unsigned long val,
int shift
)
{
shift &= 0x1f;
val = (val>>(0x20 - shift)) | (val << shift);
return val;
}
unsigned __cdecl _rotl (
unsigned val,
int shift
)
{
shift &= 0x1f;
val = (val>>(0x20 - shift)) | (val << shift);
return val;
}
unsigned __int64 __cdecl _rotl64 (
unsigned __int64 val,
int shift
)
{
shift &= 0x3f;
val = (val>>(0x40 - shift)) | (val << shift);
return val;
}
#endif