/ 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)
	KSF		/ VRS: Key struck?
	JMP     START
	KCC		/ VRS: Toss the character
	JMP I .+1	/ VRS: Yes, return to OS/8
	7600
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,      .-.
$