Motorola DSP56000, 24-Bit Digital Signal Processor manual Benchmark Programs

BENCHMARK PROGRAMS

;All coefficients are divided by 2:

;w(n)/2=x(n)/2-ai1/2*w(n-1)-ai2/2*w(n-2)

;y(n)/2=w(n)/2+bi1/2*w(n-1)+bi2/2*w(n-2)

;	X Memory Organization			Y Memory Organization
;					b1N/2	Coef. + 4*nsec - 1
;					b2N/2
;					a1N/2
;					a2N/2
;		wN(n-1)	Data + 2*nsec - 1		•
;		wN(n-2)			•
;		•			b11/2
;		•			b21/2
;		w1(n-1)			a11/2
;	R0 ➡	w1(n-2)	Data	R4 ➡	a21/2	Coef.

;

;*********************************************************************************************************************

;initialization ;*************************************

nsec	equ	4
start	equ	$40
data	equ	0
coef	equ	0
input	equ	$ffe0
output	equ	$ffe1
igain	equ	0.5
	ori	#$08,mr	;set scaling mode
	move	#data,r0	;point to filter states
	move	#coef,r4	;point to filter coefficients
	move	#2*nsec - 1,m0
	move	#4*nsec - 1,m4
	move	#igain,y1	;y1=initial gain
	opt	cc
;		filter loop: 4*nsec + 9
;*********************************************************************
	movep	y:input,y0			;get sample
	mpy	y0,y1,a	x:(r0) +,x0	y:(r4)+,y0	;x0=1st section w(n-2),y0=ai2/2
;
	do	#nsec,end_cell			;do each section
	mac	-x0,y0,a	x:(r0) -,x1	y:(r4) +,y0	;x1=w(n-1),y0=ai1/2
	macr	-x1,y0,a	x1,x:(r0) +	y:(r4) +,y0	;push w(n-1) to w(n-2),y0=bi2/2
	mac	x0,y0,a	a,x:(r0)+	y:(r4) +,y0	;push w(n) to w(n-1),y0=bi1/2
	mac	x1,y0,a	x:(r0) +,x0	y:(r4) +,y0	;next iter:x0=w(n-2),y0=ai2/2
end_cell
	rnd	a			;round result
	movep	a,y:output			;output sample

;**************************************************************************************** end

Figure B-5 Real Input FFT Based on Glenn Bergland Algorithm (Sheet 5 of 8)

B - 16 BENCHMARK PROGRAMS MOTOROLA