Motorola DSP56000 manual Figure B-2 Radix 2, In-Place, Decimation-In-Time FFT Sheet 1

BENCHMARK PROGRAMS

;This program originally available on the Motorola DSP bulletin board. ;It is provided under a DISCLAIMER OF WARRANTY available from ;Motorola DSP Operation, 6501 William Cannon Drive, Austin, TX, 78735

;

;Radix-2, In-Place, Decimation-In-Time FFT (smallest code size).

;
;Last Update 30 Sep 86		Version 1.1
;
fftr2a	macro	points,data,coef
fftr2a	ident	1,1
;

;Radix-2 Decimation-In-Time In-Place FFT Routine

;

;Complex input and output data

;Real data in X memory

;Imaginary data in Y memory

;Normally ordered input data

;Bit reversed output data

;Coefficient lookup table

;-Cosine values in X memory

;-Sine values in Y memory

;
;Macro Call — ffr2a		points,data,coef
;
;	points		number of points (2-32768, power of 2)
;	data		start of data buffer
;	coef		start of sine/cosine table
;
;Alters Data ALU Registers
;	x1	x0	y1	y0
;	a2	a1	a0	a
;	b2	b1	b0	b
;
;Alters Address Registers
;	r0	n0	m0
;	r1	n1	m1
;		n2
;
;	r4	n4	m4
;	r5	n5	m5
;	r6	n6	m6
‘
‘Alters Program Control Registers
;	pc	sr
;

;Uses 6 locations on System Stack

;

Figure B-2 Radix 2, In-Place, Decimation-In-Time FFT (Sheet 1 of 2)

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