From: "Daniel Kadenbach" <kadenbach DOT h AT primus-online DOT de>
Newsgroups: comp.os.msdos.djgpp
Subject: înterrupt problem
Date: Wed, 12 May 1999 22:11:31 +0200
Organization: Debitel Network Services GmbH
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

Hi all !

I am just trying to program a serial-port-interface (via uart-programming)
and therefore need to bend the
irq of the com2 port to my own function, but i don´t get it to work ...

My code looks like this:

 new_handler.pm_offset   = (int)int_uart;
 new_handler.pm_selector = _go32_my_cs();
  _go32_dpmi_get_protected_mode_interrupt_vector(0xb, &old_handler);
  _go32_dpmi_allocate_iret_wrapper(&new_handler);
  _go32_dpmi_set_protected_mode_interrupt_vector(0xb,&new_handler);

the Interrupt function:

static int int_uart( void )
{
  asm("cli; pusha");
  test++;

  outportb(0x20, 0x20);
  asm("popa; sti");
}

...so test should be increased if an irq occurs, but it doesn´t...

I managed to get it to work under dos by additionally masking the irq via
port 21h, but that crashes under win95, so there should be an other way...
(i´ve also seen some source-code which uses the allegro-function
_install_irq(...) for this task, but i am not able to use it in my code... )

hope someone can help me, thanx !

the lost Seeker

aka Daniel Kadenbach