/ Kaleidoscope program for the VC8E/VR14 scope.
/ Based on suggestions from page 6-19 of the Small Computer
/ Handbook, 1973.

/ The advice given is to experiment with settings of
/ the switch register bit positions 9, 10 and 11, leaving
/ all higher bits zero.  The advice is good; this is a
/ nice "screen saver" for non-storage scopes.

DISD=6052
DILX=6053
DILY=6054
DIXY=6055

*       200
START,  TAD     Y
	JMS     SCALE
	CMA
	TAD     X
	DCA     X       / X = X - SCALE(Y)
	TAD     X
	DILX
	JMS     SCALE
	TAD     Y
	DILY
	DISD
	JMP     .-1
	DIXY
	DCA     Y       / Y = Y - SCALE(X)
	JMP     START

X,      3777            / any initial value works, but
Y,      6               / 0,0 is least interesting.


/ Divide AC by 2**SR
SCALE,  .-.
	DCA     TEM
	OSR
	CIA
	DCA     C
	TAD     TEM
	CLL
	SPA
	CML
	RAR             / Arithmetic right shift
	ISZ     C
	JMP     .-5
	JMP I   SCALE

TEM,    .-.
C,      .-.

	$