POPUP INTERRUPT and Returns

[Thomas Tierney]

Hey all,

I am trying to create a TSR. This is done with the following code

'we need to create the popup
lResult = SetMem(-500000)


Popup Interrupt &H14, 0, off, off

Do
	popup sleep
	'what function was called
	lResult = Reg(%AX)
	if lResult = &H1C00 then
		lPort = REG(%DX)
		Reg %AX, &H1954
	End if 
Loop

I am calling the interrupt with this code

 Port%=P%
        REG 1,&H1C00
        REG 4,Port%
        CALL INTERRUPT &H14
        lResult% = Reg(1)
        IF lResult%=&H1954 THEN 
            Print "GOOD"
        Else
            Print "BAD"
        End if

This runs well but for the life of me I can not get the return value of &H1954, any ideas?

TIA

[Michael Mattias]

> any ideas?

Only the obvious..

if lResult = &H1C00 then

Is this ever true? I don't see that you test for it.

[Thomas Tierney]

In this case lResult is always = &HC100

[Steve Rossell]

The REG statement and function can be used to communicate via a register array in both directions with a TSR. This is outlined in chapter 14 of the PowerBASIC For DOS Reference Guide.

[Thomas Tierney]

Steve,

I am looking at chapter 14, where is it?

THanks

[Steve Rossell]

Sorry, it is in the User's Guide...page 224

[Thomas Tierney]

For some reason I can not get the value returned

Prog1.bas

lResult = SetMem(-500000)
PopUp Interrupt &H14, 0, Off, Off
Do
   PopUp Sleep
   'what function was called
   lResult = Reg(%AX)
   REG %AX, &H1954
Loop

Prog2.bas

   REG 1, &H1C00
   Call interrupt &H14
   Print Hex$(REG(1))

Do I need to perform another interrupt? or must I set the value using an ASM etc...

[Jerry Mason]

I think your last sentence is correct, Thomas. According to my reference guide, the REG statement does not load the register, it loads a register buffer that gets written to the register on the next CALL INTERRUPT. So load the register directly in your popup by replacing

REG %AX, &H1954

with

ASM MOV AX, &h1954

[Thomas Tierney]

I have tried it. Before doing the ASM statement I would get 1C00 as the return meaning that the registers are unchanged. Now when I do ASM MOV AX, &HXXXX I get 1900 for any value of XXXX.

Thanks Jerry.

[Thomas Tierney]

Steve,

I looked at page 224 in the users guide and there is no mention whatsoever on how to return values from the POPUP INTERRUPT back to the calling program. I did see an article in a newsgroup with an example on how to do this but it assumes that the developer has access to the calling programs source code which I do not have. Any help would be appreciated.

Thanks

[Michael Mattias]

... how to return values from the POPUP INTERRUPT back to the calling program ....assumes that the developer has access to the calling programs source code which I do not have

Huh?

If you do not have access to the calling program's source code, how can you do 'anything' with any return value? For that matter, what does the program do with it?

If this is some kind of "documented interface" to this program, I'd be interested in seeing the key points of that interface description... and your desciption of what you are trying to do with it.

Generally a TSR just does 'everything' and the program which is running at the time is totally agnostic about it - it does not know nor does it care.

Disclaimer: I have not done anything with PB/DOS for at least five years. But I did a lot with PB/DOS TSRs prior to that... in fact, that was my first paying job as an independent consultant (1994) so I doubt I will ever forget.

($250.00 if you wanted to know).


MCM

[Thomas Tierney]

Michael,

the sample program I was speaking of was actually posted by you quite awhile ago. What I am specifically referring to is a program that issues an interrupt then it decides on what to do with the results. What I am doing is creating an "emulator" for that interrupt and its functions so that I can bridge the communications between the actual sequence of calls in the 16 bit app to a TCP/IP Socket. I know what the responses from the TSR should be based on the spec for this interrupt.

BTW: the interrupt and its functions are in Ralph Browns Interrupt List under &14H (FOSSIL DRIVER API)

[Michael Mattias]

Well, I dug out the help...

POPUP INTERRUPT int%, ticks%, ON|OFF, ON|OFF

The interrupt number may be defined only once, before the first
POPUP SLEEP. int sets interrupt number to "hook". ticks sets timeout
limit in ticks (18.2 per second). The first ON|OFF controls execution
or "chain" of the prior interrupt handler upon entry - typically on - if
on, whenever the interrupt is executed, the prior handler is called
immediately (even if the POPUP is active, therefore "busy"); when
complete, POPUP is attempted per the usual rules. The second ON|OFF
controls execution or "chain" of the prior interrupt handler upon exit
from the POPUP, typically off. One-way communication is possible:
upon POPUP, callers registers are stored in the REG array.

A couple of things come to mind:

First, your POPUP statement:

Popup Interrupt &H14, 0, off, off

This is way (way) outside my expertise, but it seems to me that if the interrupt is supposed to 'respond', at least one (the second one) of those "off" should be an "on" (I did NOT go hunting for the Ralf Brown List).

Second, the help talks about "one-way" communication. Maybe that's true and you have hit some kind of barrier if you create your TSR with PB/DOS; i.e., you may just have to write your TSR 100% in assembly language.

MCM

[Thomas Tierney]

Thanks Michael!!

I tried
PopUp Interrupt &H14, 18, Off, on
with !mov ax, &hxxxx

this always returns &H1900 no matter what the value of xxxx is

I tried
PopUp Interrupt &H14, 18, On, off
with !mov ax, &hxxxx

this just hangs

I tried
PopUp Interrupt &H14, 18, On, On
with !mov ax, &hxxxx

this just throws an NTVDM error, Steve Rossel implies in an earlier statement that two way is possible and explained in the book which I do not see, I also have an email into support and am hoping to hear from them sometime today.

Thanks

[Thomas Tierney]

Confirmed from PB Support - this is one way communication only, need to find another method

Thanks for the help all!!

[Michael Mattias]

>need to find another method

1. Save in, read from disk file will work.

2. In PB/DOS, another way to do it is to reserve some upper memory by using MEMSET (must use in both programs, IIRC), and read and write the integer value above that address somewhere.

3. Check out pbvUserArea. That says its only for RUN/CHAIN, so that probably will NOT work.

4.(Old faithful)... appropriate a couple of bytes (all you need to store is a 16-bit integer, right?) from an unused video page. For that matter, you could use a couple of bytes from a USED video page, just use something in a corner somewhere and nobody will ever notice.

MCM