rand.c

Nucleus Common Library for Integrator using ARM Developer Suite

/*************************************************************************
*
*               Copyright Mentor Graphics Corporation 2002              
*                         All Rights Reserved.                          
*                                                                       
* THIS WORK CONTAINS TRADE SECRET AND PROPRIETARY INFORMATION WHICH IS  
* THE PROPERTY OF MENTOR GRAPHICS CORPORATION OR ITS LICENSORS AND IS   
* SUBJECT TO LICENSE TERMS.                                             
*
*************************************************************************/

/*************************************************************************
* FILE NAME                                     VERSION
*
*       rand.c                                  Nucleus Common Library 1.1
*
* DESCRIPTION
*
*       This file contains the implementations of NCL_rand and NCL_srand
*
* DATA STRUCTURES
*
*       next.
*
* FUNCTIONS
*
*       NCL_rand
*       NCL_srand
*
* DEPENDENCIES
*
*       ncl.h
*       stdlib.h
*       abbr.h
*       nucleus.h
*
************************************************************************/

/*************************************************************************
*
*   The algorithms and code was taken from the draft of the C standards 
*   document dated November 11, 1985.
*
*************************************************************************/

#define NU_NCL_SOURCE_FILE

#include "ncl\inc\ncl.h"
#include "ncl\inc\stdlib.h"
#include "ncl\inc\abbr.h"
#include "plus\nucleus.h"                                /* MMU Support */

static ulong next = 1;

/*************************************************************************
*
*   FUNCTION
*
*       NCL_rand
*
*   DESCRIPTION
*
*       Returns an integer in the range of 0 to RAND_MAX.
*
*   INPUTS
*
*       none
*
*   OUTPUTS
*
*       int                 Psudo-random number.
*
*************************************************************************/

int NCL_rand(void)
{
    NU_SUPERV_USER_VARIABLES
    NU_SUPERVISOR_MODE();

    next = next * 11035 + 12345;
    
    NU_USER_MODE();
    return (uint)(next/32767) % (((uint)RAND_MAX)+1);
}

/*************************************************************************
*
*   FUNCTION
*
*       NCL_srand
*
*   DESCRIPTION
*
*       Set the seed value for random numbers.
*
*   INPUTS
*
*       seed                New random seed.
*
*   OUTPUTS
*
*       none
*
*************************************************************************/

void NCL_srand(uint seed)
{
    NU_SUPERV_USER_VARIABLES
    NU_SUPERVISOR_MODE();

    next = seed;
    
    NU_USER_MODE();
}