X-Authentication-Warning: delorie.com: mail set sender to djgpp-bounces using -f
From: "Jordar" <rrcdaniel AT sbcglobal DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: porting from borland
Date: 6 Nov 2006 08:50:01 -0800
Organization: http://groups.google.com
Lines: 30
Message-ID: <1162831801.086285.199260@h54g2000cwb.googlegroups.com>
NNTP-Posting-Host: 65.67.51.194
Mime-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
X-Trace: posting.google.com 1162831806 5571 127.0.0.1 (6 Nov 2006 16:50:06 GMT)
X-Complaints-To: groups-abuse AT google DOT com
NNTP-Posting-Date: Mon, 6 Nov 2006 16:50:06 +0000 (UTC)
User-Agent: G2/1.0
X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.7) Gecko/20060909 Firefox/1.5.0.7,gzip(gfe),gzip(gfe)
Complaints-To: groups-abuse AT google DOT com
Injection-Info: h54g2000cwb.googlegroups.com; posting-host=65.67.51.194;
   posting-account=rQ0tLw0AAABlxfVSZZfLGXLmQpwv2fH6
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
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