heintze@fmcsse.enet.dec.com (Siegfried Heintze) (09/04/90)
I'm wondering what options there are for solving programming problems with MSDOS. I have posted the following query in other MSDOS.PROGRAMMING news groups and I am still hoping for some responses from VNEWS readers. I would like to query for suggestions on other means of investigating my problem of MSDOS hanging when I call INT 0x33 FUNC 2. I can think of (1) Books on the subject. I have looked thru several - none address this specific issue. There is one expensive book called (something like) "MSDOS System programming" that gives an example in text mode but not graphics. (2) Calling MS customer support. Is there such an animal for detailed programming questions? What is the phone number and how much does it cost? (3) Buying one of those expensive disassemblers to disassemble my mouse driver and possibly part of MSDOS to better understand exactly what is happening when I use an INT 33 FUNC 2. (4) Buying one of those very expensive debuggers like periscope for ~$400. I don't know enough about them to know exactly how they could help me - but for that price they ought to be able to work miracles. Which option would you recommend? Can you think of other options? Thanks, Sieg ======================================================================= Here is the original query I have posted in COMP.OS.MSDOS.PROGRAMMING: I'm using MSDOS software interrupt 0x33, function 0x0c to establish a routine (called ime) to be called by the mouse driver everytime the mouse changes state (ie, everytime a button is depressed or released or the position of the mouse changes.) This works because I can call the zortech routine "sound_click()" to verify that it is working. I remember reading somewhere that it is necessary to call interrupt 0x33 function 2 before writing to the VGA to prevent a conflict. This function hides the mouse pointer on the VGA to prevent the mouse driver and you from trying to access VGA simultaneously. This is an important consideration because writing to the VGA is not an atomic operation. It consists of writing to multiple VGA registers via I/O ports. Interrupting this sequence with another write sequence would not be desireable. So we tell the mouse driver not update the mouse pointer on the VGA while we are accessing the VGA display RAM and when we are done we use INT 0x33 func 1 to display the mouse pointer again. I tried just writing to the VGA display from the routine called by INT 0x33 func 0x0c and it did not hang. But when I tried to write a character to the VGA display using a call to MSDOS (INT 0x10 func 9) it hangs. No surprise, I probably needed to hide the mouse. So I call int 0x33 func 2 to hide the mouse inside ime. This hangs my machine. Why? How do I diagnose this problem further? Sieg