/* SPE-Teil des Cell-Programms zur Berechnung von Pi nach dem Schrotflinten-Algorithmus */

/**************************
 * Peter Vaeterlein, 2008 *
 **************************/

#include <spu_intrinsics.h>
#include <spu_mfcio.h>
#include <stdlib.h>
#include <stdio.h>
#include "pi_libspe.h"

float compute_pi( long int seed, 
				  uint64_t rounds )
{
	uint64_t i;
	uint64_t in = 0;
	float x, y;
	unsigned long int h;

	srand48( seed );
	
	for ( i = 0; i < rounds; i++ ) {
		x = (float) lrand48()/RAND_MAX;
		y = (float) lrand48()/RAND_MAX;
		
		if (( x * x + y * y ) < 1.0 ) {
			in++;
		}
	}
	
	return ( float ) 4.0 * in / rounds;	
}

int main ()
{
	uint32_t ea_block_h, ea_block_l;
	uint32_t tag_id;
	spe_par_t spe_par 
	    __attribute__ ((aligned(16)));
	
	ea_block_h = spu_read_in_mbox();
	ea_block_l = spu_read_in_mbox();
	
	tag_id = mfc_tag_reserve();
	
	spu_mfcdma64( &spe_par, ea_block_h,
		ea_block_l, sizeof( spe_par_t ),
		tag_id, MFC_GET_CMD );
	mfc_write_tag_mask( 1 << tag_id );
	mfc_read_tag_status_all();
	
	spe_par.value = compute_pi( 
		spe_par.seed, spe_par.rounds );
	
	spu_mfcdma64( &spe_par, ea_block_h,
		ea_block_l, sizeof( spe_par_t ),
		tag_id, MFC_PUT_CMD );
	mfc_write_tag_mask( 1 << tag_id );
	mfc_read_tag_status_all();
		
	mfc_tag_release( tag_id );
		
	return 0;
}