Motorola DSP96002 - Manual (Page 716)

MOTOROLA DSP96002 USER’S MANUAL B-197
tst d0 ;set the correct flags
rts
mszero move x:(r0+ls),d0.l ;get ls
tst d0 #0,d2.l ;check if ls = 0
jne sgntst ;if not, check sign
tst d2 ;set the correct flags
rts
;
; END OF DPLIB
;
end
; Double precision FIR example
;
; "data" and "coef" are assumed to be in DPLIB format.
; Other variables are assumed to be in IEEE DP format.
;
org x:0
ntaps equ 8
data ds 4*ntaps
coef ds 4*ntaps
p ds 1
a ds 1
ieee_in ds 1
ieee_out ds 1
;
org p:$100
start
move #data,r2 ;point to data
move #coef,r3 ;point to coefficients
move #p,r4 ;temp product
move #a,r5 ;product accumulator
move #4,n2 ;dp size
move n2,n3
move #4*ntaps-1,m2 ;mod buffer size
move m2,m3
_loop
move l:ieee_in,d0.d ;get ieee number
move r2,r0 ;point r0 to data buffer
jsr ieee2dplib ;convert register to dp and save
do #ntaps,_dpfir
move r4,r0 ;point to product variable
move r3,r1 ;point to coefficients
jsr dp_mpy ;multiply, result in p
move r5,r0 ;point to accumulations
move r4,r1 ;point to product variable
jsr dp_add ;add them together
move (r2)+n2 ;shift to next dp data value
move (r3)+n3 ;move to next dp coefficient
_dpfir
move r5,r0 ;point to result
jsr dplib2ieee ;convert to a value in d0