From:	mauch AT uni-duisburg DOT de (Michael Mauch)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Parallel port/Interrupt handling - please help me
Date:	Tue, 21 Jan 1997 21:51:08 +0100
Organization:	Home, sweet home (via Gesamthochschule Duisburg)
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References:	<32E2363F DOT 41C6 AT exp-math DOT uni-essen DOT de>
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To:	djgpp AT delorie DOT com
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[mailed & posted]

On Sun, 19 Jan 1997 15:57:03 +0100, Peter Gober
<gober AT exp-math DOT uni-essen DOT de> wrote:

> I would be really very thankful if someone could give me a hint.

There is a difference between so-called "software interrupts" (INTs),
i.e. the interrupt vectors, and "hardware interrupts" (IRQs), i.e. the
interrupts lines.

Here's a snippet from Ralf Brown's Interrupt List:

INT 08 - IRQ0 - SYSTEM TIMER; CPU-generated (80286+)
INT 09 - IRQ1 - KEYBOARD DATA READY; CPU-generated (80286,80386)
INT 0A - IRQ2 - LPT2/EGA,VGA/IRQ9; CPU-generated (80286+)
INT 0B - IRQ3 - SERIAL COMMUNICATIONS (COM2); CPU-generated (80286+)
INT 0C - IRQ4 - SERIAL COMMUNICATIONS (COM1); CPU-generated (80286+)
INT 0D - IRQ5 - FIXED DISK/LPT2/reserved; CPU-generated (80286+)
INT 0E - IRQ6 - DISKETTE CONTROLLER; CPU-generated (80386+)
INT 0F - IRQ7 - PARALLEL PRINTER
INT 70 - IRQ8 - CMOS REAL-TIME CLOCK
INT 71 - IRQ9 - REDIRECTED TO INT 0A BY BIOS
INT 72 - IRQ10 - RESERVED
INT 73 - IRQ11 - RESERVED
INT 74 - IRQ12 - POINTING DEVICE (PS)
INT 75 - IRQ13 - MATH COPROCESSOR EXCEPTION (AT and up)
INT 76 - IRQ14 - HARD DISK CONTROLLER (AT and later)
INT 77 - IRQ15 - RESERVED (AT,PS); POWER CONSERVATION (Compaq)

This means that you have to use the INT-number (i.e. lptIRQ+8) when
calling _go32_dpmi_set_protected_mode_interrupt_vector().

Oops, and I think you should declare your counter variable to be
volatile.

Regards...
		Michael

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