Motorola DSP96002 - Manual (Page 595)

B-76 DSP96002 USER’S MANUAL MOTOROLA
B.1.42 Signed Reciprocal Generation
This generates a fast approximation to 1/x.
Approximation of 1/d1 Program ICycles
16 Bit Accuracy Words
fseedd d1,d6 1 1
fmpy.s d1,d6,d1 #2.0,d4.s 2 2
fsub.s d1,d4 1 1
fmpy.s d6,d4,d1 1 1
--- ---
Totals: 5 5
Approximation of 1/d1
Program ICycles
32 Bit Accuracy Words
fseedd d1,d6 1 1
fmpy.s d1,d6,d1 #2.0,d4.s 2 2
fsub.s d1,d4 d4.s,d3.s 1 1
fmpy.s d1,d4,d1 1 1
fmpy d6,d4,d1 fsub.s d1,d3 1 1
fmpy.s d1,d3,d1 1 1
--- ---
Totals: 7 7
B.1.43 Line Drawing
B.1.43.1 Floating-Point Incremental Line Drawing Algorithm
This algorithm generates points along a line given the endpoints. As the coordinate along one axis is incre-
mented in fixed point, the other coordinate is incremented in floating-point and then converted to fixed
point. A full line drawing algorithm which draws lines in all directions is given below.
Registers:
d0 = temporary d4 = temporary x1 d8 =
d1 = temporary d5 = temporary y1 d9 = 2.0
d2 = x1 (dx) d6 = x0 and xScreen
d3 = y1 (dy) d7 = y0 and yScreen