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C
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2001-01-01 00:00:00 +01:00
/***
*rand.c - random number generator
*
* Copyright (c) 1985-1993, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines rand(), srand() - random number generator
*
*Revision History:
* 03-16-84 RN initial version
* 12-11-87 JCR Added "_LOAD_DS" to declaration
* 05-31-88 PHG Merged DLL and normal versions
* 06-06-89 JCR 386 mthread support
* 03-15-90 GJF Replaced _LOAD_DS with _CALLTYPE1, added #include
* <cruntime.h> and fixed the copyright. Also, cleaned
* up the formatting a bit.
* 04-05-90 GJF Added #include <stdlib.h>.
* 10-04-90 GJF New-style function declarators.
* 07-17-91 GJF Multi-thread support for Win32 [_WIN32_].
* 02-17-93 GJF Changed for new _getptd().
*
*******************************************************************************/
#include <cruntime.h>
#include <os2dll.h>
#include <stddef.h>
#include <stdlib.h>
#ifndef MTHREAD
static long holdrand = 1L;
#endif
/***
*void srand(seed) - seed the random number generator
*
*Purpose:
* Seeds the random number generator with the int given. Adapted from the
* BASIC random number generator.
*
*Entry:
* unsigned seed - seed to seed rand # generator with
*
*Exit:
* None.
*
*Exceptions:
*
*******************************************************************************/
void _CRTAPI1 srand (
unsigned int seed
)
{
#ifdef MTHREAD
#ifdef _CRUISER_
struct _tiddata * tdata;
tdata = _gettidtab(); /* get tid's data address */
tdata->_holdrand = (long)seed;
#else /* ndef _CRUISER_ */
#ifdef _WIN32_
_getptd()->_holdrand = (unsigned long)seed;
#else /* ndef _WIN32_ */
#error ERROR - ONLY CRUISER OR WIN32 TARGET SUPPORTED!
#endif /* _WIN32_ */
#endif /* _CRUISER_ */
#else
holdrand = (long)seed;
#endif
}
/***
*int rand() - returns a random number
*
*Purpose:
* returns a pseudo-random number 0 through 32767.
*
*Entry:
* None.
*
*Exit:
* Returns a pseudo-random number 0 through 32767.
*
*Exceptions:
*
*******************************************************************************/
int _CRTAPI1 rand (
void
)
{
#ifdef MTHREAD
#ifdef _CRUISER_
struct _tiddata * tdata;
tdata = _gettidtab(); /* get tid's data address */
return(((tdata->_holdrand = tdata->_holdrand * 214013L + 2531011L) >>
16) & 0x7fff);
#else /* ndef _CRUISER_ */
#ifdef _WIN32_
_ptiddata ptd = _getptd();
return( ((ptd->_holdrand = ptd->_holdrand * 214013L
+ 2531011L) >> 16) & 0x7fff );
#else /* ndef _WIN32_ */
#error ERROR - ONLY CRUISER OR WIN32 TARGET SUPPORTED!
#endif /* _WIN32_ */
#endif /* _CRUISER_ */
#else
return(((holdrand = holdrand * 214013L + 2531011L) >> 16) & 0x7fff);
#endif
}