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From:	"Jordar" <rrcdaniel AT sbcglobal DOT net>
Newsgroups:	comp.os.msdos.djgpp
Subject:	porting from borland
Date:	6 Nov 2006 08:50:01 -0800
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Reply-To:	djgpp AT delorie DOT com

Hi,

I am porting a program over to DJGPP from borland 5.01.  It wasn't too
bad. In fact it was too easy...
My program compiles and runs but my interrupts never are called.  I did
some digging into this problem and found that it seems like the PIC
itself is never enabled because inportb/outportb behave erratically.

Here is an example.  I am trying to enable IRQ 5.  So I:

IMR = inport(0x21);           // read in the current status of enabled
interrupts:
IMR &= ~(1 << 5);             // Clear desired bit (this enables
interrupt 5)
outportb(0x21, IMR);               // Out new IMR value to the PIC.


Next I check to see if this new value was written to the PIC:
cprintf("0x21 %02X - IMR %02X ",inportb(0x21),IMR);

However The value written and the value read do not match.
Instead the inported value is 0xF8, while I just outported 0xD8.....

So I can never enable interrupts since the PIC doesn't get writtent o
properly.

Has anyone experienced something similar?  Any ideas?

Jordar

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