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

BENCHMARK PROGRAMS

move	#twiddle+1,r7
lua	(r0)+n0,r1
move	r0,r4
move	r1,r5
move	#1,r3
move	x:(r0),A	y:(r4),y0

do n0,pass1

;------------------------------------------------

;First Pass -- W(n) = 1

;

;A---\ /---A’= Re[ A + jB + (C + jD) ] = A + C

;B----\__/----B’= Im[ A + jB + (C + jD) ] =j(D + B)

;C----/ \----C’= Re[ A + jB - (C + jD) ] = A - C

;D---/ \---D’= Im[-A - jB + (C + jD) ] =j(D - B)

;-------------------------------------------------
;
sub	y0,A	x:(r1),x0 y:(r5),B
add	x0,B	A,x:(r1)+		y:(r5),A
sub	x0,A	x:(r0)+,B		B,y:(r4)+
add	y0,B	x:(r0)-, A A,y:(r5)+
move	B,x:(r0)+		y:(r4),y0
pass1
move	#idata,r0
do	#binlogsz-3,end_pass
move	r7,r2
move	r2,r6
move	n0,A
lsr	A r3,B
lsl	A,n0
move	B,r3
lua	(r0)+n0,r1
move	r0,r4
move	r1,r5
lua	(r3)-,n2
move	x:(r0),A		y:(r4),y0
do n0,FirstGroupInPass
sub	y0,A	x:(r1),x0		y:(r5),B
add	x0,B	A,x:(r1)+ y:(r5),A
sub	x0,A	x:(r0)+,B B,y:(r4)+
add	y0,B	x:(r0)-,A A,y:(r5)+
move	B,x:(r0)+		y:(r4),y0
FirstGroupInPass
do	n2,end_group
move	r5,r0
move	r0,r4

;r7 always points to start location of twiddle ;r1 = ptr to b

;r4 points to c

;r5 points to d,with predecrement ;group per pass, double at ea pass ;A=a, y0=c

;first pass is trivial, no multiplications

;A=a-c=c’,B=d,x0=b, ;B=d+b=b’, A=d,PUT c’ to x:b ;A=d-b=d’,B=a,PUT b’ to y:c ;B=a+c=a’, A=next a,PUT d’ ;y0=next c, PUT a’

;r0 = ptr to a

;do all passes except first and last ;r2 points to real twiddle

;r6 points to imag twiddle ;half bflys per group ;double group per pass

;r3 is temp reg. ;r1 = ptr to b ;r4 points to c ;r5 points to d ;n2=group per pass -1 ;A=a, y0=c

;first group in a pass ;A=a-c=c’,B=d,x0=b, ;B=d+b=b’, A=d,PUT c’ to x:b ;A=d-b=d’,B=a,PUT b’ to y:c ;B=a+c=a’, A=next a,PUT d’ ;y0=next c, PUT a’

;rest groups in this pass ;r0 ptr to next group a ;r4 ptr to next group c

MOTOROLA BENCHMARK PROGRAMS B - 23