$FFC0

page 132,60,1,1 ;newlms2n.asm

;New Implementation of the delayed LMS on the DSP56000 Revision C ;Memory map:

;	Initial X					H
;	x(n)	x(n-1)	x(n-2) x(n-3)		x(n-4)	hx	h0	h1 h2	h3
;	]					]	]
;	r0					r5	r4
;hx is an unused value to make the calculations faster.
;	opt	cc
	opt	cc
ntaps		equ	4
input		equ	$FFC0
output		equ	$FFC1
	org	x:$0
state		ds	5
	org	y:$0
coef		ds	5
;
	org	p:$40
	move	#state,r0		;start of X
	move	#2,n0
	move	#ntaps,m0		;mod 5
	move	#coef +1,r4		;coefﬁcients
	move	#ntaps,m4		;mod 5
	move	#coef,r5		;coefﬁcients
	move	m4,m5		;mod 5
_smploop						;			Prog	Icyc
	movep			y:input,a		;get input sample			word
	move		a,x:(r0)			;save input sample			1	1
;error signal is in y1
;FIR sum in a=a+h(k) old*x(n-k)
;h(k)new in b=h(k)old + error*x(n-k-1)
	cir	a	x:(r0)+,x0			;x0=x(n)			1	1
	move		x:(r0)+,x1	y:(r4)+,y0		;x1=x(n-1),y0=h(0)			1	1
	do	#taps/2,_lms				;			2	3
	mac	x0,y0,a	y0,b	b,y:(r5)+		;a=h(0)*x(n),b=h(0)			1	1
	macr	x1,y1,b	x:(r0)+,x0	y:(r4)+,y0		;b=h(0)+e*x(n-1)=h(0)new			1	1
						;x0=x(n-2) y0=h(1)
	mac	x1,y0,a	y0,b	b,y:(r5)+		;a=a+h(1)*x(n-1) b=h(1)			1	1
	macr	x0,y1,b	x:(r0)+,x1	y:(r4)+,y0		;b=h(1)+e*x(n-2)			1	1
;						;x1=x(n-3) y0=H(2)
_lms
	move			b,y:(r5)+		;save last new c( )			1	1
	move		(r0) -n0			;pointer update			1	1
;(Get d(n), subtract ﬁr output (reg a), multiply by “u”, put
;the result in y1. This section is application dependent.)
	movep		a y:output			;output ﬁr if desired

Figure B-5 Real Input FFT Based on Glenn Bergland Algorithm (Sheet 7 of 8)

B - 18