Date   : Sun, 08 Jul 1984 02:25:00-EDT
From   : Paul L. Kelley <PLK@Mit-Mc.ARPA>
Subject: movcpm synchronization errors

		BDOS jump checking in MOVCPM.


	LXI	B,STORAGE	;MOVCPM has already read the presumed address
				;of the running BDOS from 0006 and stored it
				;away
	LDAX	B		;get least significant byte of running BDOS
				;address
	CPI	6		;is it really BDOS or perhaps DDT?
	MVI	A,0		;get ready to put the address of the running
				;serial number in STORAGE
	JNZ	SYNCERR		;give synchronization error if not the correct
				;BDOS address modulo a page
	STAX	B		;STORAGE now has address of start of running
				;serial number


		Serial number checking in MOVCPM.

	
	LXI	D,MOVCPM$SERNO	;location of serial number in MOVCPM's
				;relocatable version of BDOS. This is at
				;the start of the relocatable BDOS.
	LHLD	STORAGE		;get the address of the running serial number
	MVI	C,6		;length of serial number
LOOP:	LDAX	D		;compare MOVCPM's serial number with
	CMP	M		;running BDOS's serial number
	JNZ	SYNCERR		;give synchronization error if CMP fails
	INX	H		;check
	INX	D		;	all
	DCR	C		;		six
	JNZ	LOOP		;			bytes