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From: kottke@puff.UUCP (Richard J. Kottke)
Newsgroups: net.micro.6809
Subject: Re: Request for os9 info
Message-ID: <725@puff.UUCP>
Date: Fri, 21-Mar-86 21:25:52 EST
Article-I.D.: puff.725
Posted: Fri Mar 21 21:25:52 1986
Date-Received: Sun, 23-Mar-86 01:59:40 EST
References: <8700004@hpvcla.UUCP>
Organization: U of Wisconsin CS Dept
Lines: 109
Summary: GetStat/SetStat secrets


Attempted answers to Dave Lowe's very good questions:


> What happens to os9 if it gets handed a character with the most significant
> bit set?  My input driver carefully strips the bit before passing the 
> character on. The keyboard I have has several special function keys and I
> have thought I could flag these keys with the most significant bit.

This is probably due to your input driver, as you have said; however os9 seems
to be willing to send 8-bit characters wherever they need to go (as is the case
with the disk drivers).  A little bit of work with your terminal device driver
should get the 8th. bit going.  An alternate method would be to mess around
with tmodes's "type" parameter, which is a little mysterious; my manual says
that it is for setting parity, wordlength etc. but gives no further info.


> My documentation gives precious little information about the register setup
> on the entry into a driver's interrupt routine. Could someone enlighten me?
> What is the purpose of the BITA #1 instructiS.Size
SS.Pos
SS.EOF
SS.DStat
SS.Joy
SS.Reset
SS.WTrk
SS.Feed
SS.Frz
SS.SQD
SS.DCmd

I have added SS.DSiz because on the Color Computer, the display isn't always
80 columns by 24 lines; I encourage others to utilize this status call.

About where to get at the passed parameters: they are pointed to by the PD.RGS
area of the path descriptor.  Upon entry to a GetStat or SetStat server, U 
points to the device static memory area, Y points to the PD and A holds the
status code.  To get X pointing to the register stack do this:

	LDX	PD.RGS,Y	X points to the old registers

To change the stack or look at it, do this:

	LDA	R$A,X	A gets the old A
	EORA	#$F1	Do something bizaare to A
	STA	R$A,X	Put it back

If you were to write a SCFMan - type driver, you could include these status
calls:
SS.Opt
SS.Ready
SS.Reset
SS.Feed
SS.DevNm
SS.DSiz

If you need more info on these, just drop me an e-mail letter.

						-Richard Kottke
						kottke@puff.wisc.edu
						uwvax!puff!kottke