Motorola DSP96002 - Manual (Page 600)

MOTOROLA DSP96002 USER’S MANUAL B-81
cmp d4,d2
dec d6 ifge
jsr _draw_point
_line_y_xn
rts
; Increment x case
; If dx is negative, switch endpoints and sign of dx and dy
_inc_x
tst d0
jeq _draw1
tfr d4,d6 iflt
tfr d5,d7 iflt
neg d0 iflt
neg d1 iflt
tst d1
jlt _set_x_yn
; Increment x, dy positive case
; Set up registers
_set_x_yp
lsr d0 d0.l,d2.l
dec d2 d2.l,d4.l
move d0.l,r0
move d2.l,m0
move d1.l,n0
move d1.l,d5.l
; Draw first point
jsr _draw_point
; Draw additional points
do d4.l,_line_x_yp
inc d6 r0,d2.l
add d5,d2 (r0)+n0
cmp d4,d2
inc d7 ifge
jsr _draw_point
_line_x_yp
rts
; Increment x, dy negative case
; Set up registers
_set_x_yn