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From: bright@dataioDataio.UUCP (Walter Bright)
Newsgroups: net.micro.pc
Subject: Re: Re: Identifying an iAPX series processo
Message-ID: <937@dataioDataio.UUCP>
Date: Mon, 31-Mar-86 13:23:19 EST
Article-I.D.: dataioDa.937
Posted: Mon Mar 31 13:23:19 1986
Date-Received: Wed, 2-Apr-86 20:15:42 EST
References: <7901@watrose.UUCP> <53500027@trsvax> <685@mtung.UUCP>
Reply-To: bright@dataio.UUCP (Walter Bright
Organization: Data I/O Corp., Redmond WA
Lines: 19

In article <685@mtung.UUCP> ijk@mtung.UUCP (Ihor Kinal) writes:
>P.S.  One discrepancy: the article claims that in a 286, it's
>no longer legal to say MOV CS, AX; nor can one say POP CS.
>Using DEBUG, I tried both; the MOV CS,AX seemed ok, the POP CS
>totally hung the machine. If both were true, then how could a program
>reset the CS register????

Easy:
	Use the JMP FAR instruction.
	Use the CALL FAR instruction.
	Use the RET FAR instruction. (Note that there is no mnemonic for
		this instruction in MASM 4.0. You have to muck with the
		PROC pseudo op or write a macro to do it. Ug.)
	Use the IRET instruction.
	Use the INT instruction.

If you use a MOV CS,AX, you deserve what you get. You have to be very
clever to get the IP right to execute the next instruction. A lot cleverer
than to set up a JMP FAR instruction.