Motorola DSP96002 - Manual (Page 539)

B-20 DSP96002 USER’S MANUAL MOTOROLA
;
; t3 = dr + br
; t4 = dr - br
;
; t5 = ai + ci
; t6 = ai - ci
;
; t7 = bi + di
; t8 = bi - di
;
; t9 = t2 + t8
; t10 = t2 - t8
;
; t11 = t6 + t4
; t12 = t6 - t4
;
; ar’ = t1 + t3
; t13 = t1 - t3
;
; ai’ = t5 + t7
; t14 = t5 - t7
;
; br’ = t9*wr1 + t11*wi1
; bi’ = t11*wr1 - t9*wi1
;
; cr’ = t13*wr2 + t14*wi2
; ci’ = t14*wr2 - t13*wi2
;
; dr’ = t10*wr3 + t12*wi3
; di’ = t12*wr3 - t10*wi3
;
; Address pointers are organized as follows:
;
; r0 = ar,ai,br,bi pointer n0 = butterflies per group
; r1 = wr (cos) pointer n1 = rotation factor
; r2 = temp storage pointer n2 = groups per pass
; r3 = group index counter n3 = rotation factor
; r4 = cr,ci,dr,di pointer n4 = butterflies per group
; r5 = wi (sin) pointer n5 = rotation factor