Motorola DSP96002 - Manual (Page 597)

B-78 DSP96002 USER’S MANUAL MOTOROLA
; Switch endpoints if necessary
_inc_x
ftst d2 d3.s,d0.s 1 1
ftfr.s d4,d6 fflt 1 1
ftfr.s d5,d7 fflt 1 1
; Fix x0 and dx
int d6 d2.s,d1.s 1 1
int d1 1 1
neg d1 iflt 1 1
jeq _draw1_x 2 2
; Calculate dy/dx
fseedd d2,d4 1 1
fmpy.s d2,d4,d5 d9.s,d2.s 1 1
fmpy d0,d4,d0 fsub.s d5,d2 d2.s,d3.s 1 1
fmpy.s d5,d2,d5 d2.s,d4.s 1 1
fmpy d0,d4,d0 fsub.s d5,d3 1 1
fmpy.s d0,d3,d0 d7.s,d2.s 1 1
; Draw first point
int d7 1 1
jsr _draw_point application dependent
; d0 = dy/dx d1 = dx d6 = x0 d7 = y0
do d1.l,_end_x 2 3
fadd.x d0,d2 1 1
inc d6 d2.s,d7.s 1 1
int d7 1 1
jsr _draw_point application dependent
_end_x
rts 2 2
_draw1_x
int d7 1 1
jsr _draw_point application dependent
rts 2 2
Performance:
Trivial case: (single point) 16 cycles
Other cases: 25 + 3n cycles