Hi, On Fri, 30 Dec 2005 00:16:18 +0530 Bhanu Kalyan Chetlapalli <chbhanukalyan@xxxxxxxxx> wrote: > I have a doubt with w.r.t interrupts and the IDT (Interrupt > Descriptor Table) on an i386. Volume 3 of Intel's IA-32 Intel(r) > Architecture Software Developer's Manual (System Programming Guide) > says that - Interrupt Vector Numbers 0-31 are Intel reserved, so do > not use. These are interrupt numbers, as seen from the processor. > However, on my linux machine, when I did an "cat > /proc/interrupts", the Interrupt field has values like - 0 for Timer, > 7 for parport0, 8 for RTC etc. How can this be possible? Does the > IDT's number vector points to the Exception handler (as per intel's > doc) or to the Hardware's Interrupt handler? These are IRQ numbers (i.e hardware interrupts). They correspond to other interrupt from a processor point of view. The mapping of IRQ to processor interrupts depends on how the PIC (i8259) or APIC is configured. For example, IRQ 0 is the timer. If you program the PIC to set the base IRQ to interrupt 32, then interrupt 32 will be the timer (IRQ 0), interrupt 33 will be the PS/2 keyboard (IRQ 1), etc. I don't know how it works with APIC, but I assume it's something similar. Sincerly, Thomas -- PETAZZONI Thomas - thomas.petazzoni@xxxxxxxx http://{thomas,sos,kos}.enix.org - Jabber: thomas.petazzoni@xxxxxxxxx http://{agenda,livret}dulibre.org - http://www.toulibre.org Fingerprint : 0BE1 4CF3 CEA4 AC9D CC6E 1624 F653 CB30 98D3 F7A7
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