INTCODE.TXT

BenOS v1.0 interrupt code (c) Benjamin Hoyt 1997

Whenever BenOS receives one of the following exceptions it simply
(re)enables interrupts and THROWs a value directly associated with
that exception. The interrupt numbers for these exceptions are as
follows:

int#	description
----	-----------
00		divide overflow or divide by zero
01		hardware breakpoint or trace trap
02		non-maskable interrupt
03		software breakpoint (INT 3, opcode CC)
04		overflow interrupt (for INTO instruction)
05		BOUND instruction exception
06		invalid opcode
07		device (FPU) not available
08		double fault
09		coprocessor segment overrun
0A		invalid TSS
0B		segment not present
0C		stack fault
0D		general protection fault
0E		page fault
0F		reserved
10		coprocessor error
11-1F	reserved for future expansion

BenOS maps the hardware IRQs (00-0F) from the 8259 to the CPU
interrupts 20-2F so they don't coincide with the above exceptions.
Hardware IRQs are as follows:

IRQ#	description
----	-----------
00		timer (8254)
01		keyboard (8042)
02		cascade from PIC slave
03		COM2 serial port
04		COM1 serial port
05		LPT2 printer port
06		floppy disk controller
07		LPT1 printer port
08		CMOS clock
09-0C	unused
0D		math coprocessor
0E		hard disk controller
0F		unused