From:	"Peter Remmers" <Peter DOT Remmers AT t-online DOT de>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: strange interrupt chaining problem with keyboard interrupt
Date:	Fri, 6 Oct 2000 02:21:07 +0200
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"Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il> schrieb...

> How about locking everything that the interrupt handler touches?  Did
> you do that?  The code you posted doesn't show.

I have a
int _crt0_startup_flags = _CRT0_FLAG_LOCK_MEMORY;
for starters, until everything works and I can care about locking.

> Did you try to disable the keyboard hooking in the DJGPP startup code?
> If so, did it change anything?

How do I do that? There's no _CRT0_FLAG_SOMETHING for that in crt0.h...

Meanwhile I got around it by writing my own wrapper in assembler.
I took some inspiration by looking at the allegro sources.
My C function returns a value that tells if the wrapper should chain
to the original ISR or not, which BTW works.

The problem with calling the old ISR directly from the C handler
still persists, however. More precisely, after setting up the
DJGPP execution environment (DS=ES=SS and setting up a new stack),
calling the old ISR has said effects.

Suggestion: integrate the idea of telling the wrapper with a return
value if it should chain or not into
_go32_dpmi_chain_protected_mode_interrupt_vector().
I think a lot of people would have a lot less trouble trying to
do such interrupt things...


Peter

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