Path: utzoo!utgpu!water!watmath!clyde!rutgers!mit-eddie!uw-beaver!tektronix!orca!tekecs!frip!andrew
From: andrew@frip.gwd.tek.com (Andrew Klossner)
Newsgroups: comp.os.cpm
Subject: Re: Debugging a new BIOS
Message-ID: <9703@tekecs.TEK.COM>
Date: 1 Feb 88 21:18:36 GMT
References: <581*kenw@noah.arc.cdn>
Sender: news@tekecs.TEK.COM
Organization: Tektronix, Wilsonville, Oregon
Lines: 18

[]

	"The problems it that all of these debuggers appear to use the
	BDOS to do their I/O, and this problem involves BDOS calls to
	the BIOS. Needless to say, this does bad things to the BDOS's
	internal stack ... Another complication is that, in this case,
	the CCP (or it's replacement) must be intact to handle the warm
	boot. I've whipped up a little assembler routine to fudge
	address 0005, etc., to keep the debuggers from overwriting it,
	so at least that's not a problem."

As long as that assembler routine is already there, teach it to
intercept the BDOS call, check to see if it's a terminal I/O request,
and let it through if not; if it is terminal I/O, do it directly (call
the BIOS or write directly to the UART).

  -=- Andrew Klossner   (decvax!tektronix!tekecs!andrew)       [UUCP]
                        (andrew%tekecs.tek.com@relay.cs.net)   [ARPA]