/*
	These C language subroutines implement random number 
	generation for the runtime library.

	The Run Time Library for the C Language.

	Gordon A. Sterling	(617) 461 - 3076
	DSP Development Tools Engineering

	Created on 2/14/91
	Updated on 5/94 by AS

	#include <stdlib.h>			<Header>
	void srand(int seed);			<Prototype>
	int rand(void);				<Prototype>
*/

#include "lib_glob.h"
#include "sdl_glob.h"

#define a_value	1664525
#define c_value 32767

.SEGMENT/CODE	Code_Space_Name;
.FILE RTL_FILENAME;

.GLOBAL		_rand, _srand;

_srand:		ram_ireg=___lib_rand_seed;
		JUMP (PC, restore_state) (DB);
		FETCH_RETURN
		rammem(ram_ireg,ram_0)=R4;
	

_rand:		ram_ireg=___lib_rand_seed;
		R2=a_value;		    /*Base*/
		R0=rammem(ram_ireg,ram_0);  /*Read seed value*/
		R0=R0*R2 (UUI);		    /*Compute mod(a*x)*/
		R2=c_value;		
		R0=R0+R2, FETCH_RETURN	    /*Compute mod(a*x + c)*/
		rammem(ram_ireg,ram_0)=R0;  /*Write out new seed*/
		R0=BCLR R0 BY 31;	    /*Always return positive*/

restore_state:	RETURN (DB);
		RESTORE_STACK
		RESTORE_FRAME
.ENDSEG;

.SEGMENT/RAM_SPACE 	Ram_Space_Name;

.GLOBAL	___lib_rand_seed;
.VAR	___lib_rand_seed = 1;

.ENDSEG;