Motorola DSP96002 - Manual (Page 538)

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