beautypg.com

Motorola DSP96002 User Manual

Page 538

background image

MOTOROLA

DSP96002 USER’S MANUAL

B-19

move x:(r6)+n6,d9.s y:,d8.s

fmpy d8,d7,d3 faddsub.s d4,d0 x:(r1)+n1,d6.s d5.s,y:(r4)+n4

_end_last

B.1.15.3 Radix 4 Decimation in Frequency FFT

fftr4z macro points,data,coef,table,temp

fftr4z ident 1,1

;

; Radix 4 Decimation in Frequency In-Place FFT Routine

;

; Complex input and output data

; Real data in X memory

; Imaginary data in Y memory

; Normally ordered input data

; Digit reversed output data

; Coefficient lookup table

; Full cycle sinewave in Y memory

; Coefficient table can be generated by "sinewave" macro.

;

;

; Macro Call - mfftr4z points,data,coef,table,temp

;

; points number of points (4-16384, power of 4)

; data starting address of data buffer

; coef starting address of sinewave table

; table size of sinewave table

; temp starting address of temporary storage area

;

; Cooley-Tukey Radix 4 FFT Algorithm

;

;

; ar,ai ar’,ai’

; br,bi Radix 4 br’,bi’

; cr,ci Butterfly cr’,ci’

; dr,di dr’,di’

;

;

; t1 = ar + cr

; t2 = ar - cr