;DSSET.ASM	May 11, 1988
;	Ultra-simple program that establishes a vector to the
;	DateStamper clock routine at 0008h.  This can subsequently
;	be "called" via an RST 1 (RST 8H in Zilog) instruction, as
;	in the B5C-DS.INS clock insert for BYE5.
;						Bruce Morgen

	ORG	100H

	MVI	E,'D'		; DateStamper "clue" character
	MVI	C,12		; CP/M version function number
	CALL	5		; Call BDOS Bros.
	CPI	22H		; Must be CP/M 2.2 or equivalent
	JNZ	DSERR		; Otherwise there's no DS
	MOV	A,H		; Test for returned "clue"
	CPI	'D'
	JZ	DSGOOD		; Proceed if we got it
DSERR:	LXI	D,DSERMSG	; Point to error message
	MVI	C,9		; BDOS print string function #
	JMP	5		; Return via to CCP via BDOS
DSERMSG:
	DB	7,13,10,'Can''t find The DateStamper$'
;
DSGOOD:	XCHG			; Set up vector for an RST 1
	SHLD	9
	MVI	A,0C3H
	STA	8
	RET			; Return quietly to CP/M

	END