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CONTRIBUTIONS/cpm-handbook/cpmsrc/FIG5-15.ASM

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+; Figure 5-15
+;
+;	CDISK
+;	Change Disk
+;	This subroutine displays a message requesting the
+;	to change the specified logical disk, then waits for
+;	a Carriage Return to be pressed. It then issues
+;	a Disk Reset and returns to the caller.
+;
+;	Entry Parameters
+;
+;		A = Logical disk to be changed (A = 0, B = 1)
+;
+;	Exit Parameters
+;
+;		None
+;
+;	Calling Sequence
+;
+;		MVI	A,0		;Change drive A:
+;		CALL	CDISK
+;
+;
+B$DSKRESET	EQU	13		;Disk Reset function code
+B$PRINTS	EQU	9		;Print $-terminated string
+B$CONIN		EQU	1		;Get console input
+BDOS		EQU	5		;BDOS Entry Point
+;
+CR		EQU	0DH
+LF		EQU	0AH
+;
+CDISKM:		DB	CR,LF,'Change logical disk '
+CDISKD:		DB	0
+		DB	': and press Carriage Return to continue$'
+;
+CDISK:
+	ADI	'A'-1		;Convert to Letter
+	STA	CDISKD		;Store into message
+	MVI	C,B$PRINTS	;Display Message
+	LXI	D,CDISKM
+	CALL	BDOS
+CDISKW:
+	MVI	C,B$CONIN	;Get keyboard character
+	CALL	BDOS
+	CPI	CR
+	JNZ	CDISKW
+	MVI	C,B$DSKRESET	;Now reset disk system
+	CALL	BDOS
+	RET
+