/*
	This C language subroutine computes the
	autocorrelation sequence of its floating
	point input.

	The Run Time Library for the C Language.

	Gordon A. Sterling	(617) 461 - 3076
	DSP Development Tools Engineering
    
	Created on 5/27/90
	Updated on 5/94 by AS
	Fixed bug on 10/94 where R12 becomes F12 and then in the call
 	to float divide, it gets altered.  Saved value in dmc_i.  AS

	#include <stats.h>				<Header>
	float autocorr(float out[], float in[],\	<Prototype>
		       int samples, int lags);		<Prototype>

*/

#include "lib_glob.h"
#include "sts_glob.h"

.SEGMENT/CODE	Code_Space_Name;
.FILE 		RTL_FILENAME;

.GLOBAL	    	_autocorr;

_autocorr:	put(R7);
		put(R11);
		R2=dma_i;
		put(R2);
		R2=dmb_i;
		put(R2);
		R2=dmc_i;

		F7=1.0;
		dmc_i=R12;		/* Hold value  */
		
		CALL (PC, ___float_divide) (DB);
		F11=F7+F7, put(R2);
		F12=FLOAT R12, readparam4(R1);

		R12=dmc_i;		/* Restore old value */
		R11=PASS R8, dmc_i=R4;
		LCNTR=R1, DO lag_loop UNTIL LCE;
		    R12=R12-1, dma_i=R11;
		    R0=R0-R0, dmb_i=R8;
		    F2=DM(dmb_i,1);
		    F1=DM(dma_i,1);
	    	    LCNTR=R12, DO element_loop UNTIL LCE;
			F1=F1*F2, F2=DM(dmb_i,1);
element_loop:  		F0=F0+F1, F1=DM(dma_i,1);
		    F1=F1*F2;
		    F0=F0+F1;
		    F0=F0*F7, FETCH_RETURN
lag_loop:	    R11=R11+1, DM(dmc_i,1)=F0;

restore_state:	get(dmc_i,1);
		get(dmb_i,2);
		get(dma_i,3);
		R0=PASS R4, get(R11,4);
		get(R7,5);
		RETURN (DB);
		RESTORE_STACK
		RESTORE_FRAME
.ENDSEG;