Interrupt List Release 61 Last change 16jul00
Copyright (c) 1989-1999,2000 Ralf Brown
Index for interrupt INT 08

Table of Contents by Order
08 - INT 08 C - IRQ0 - SYSTEM TIMER
08 - INT 08 C - CPU-generated (80286+) - DOUBLE EXCEPTION DETECTED


08 - INT 08 C - IRQ0 - SYSTEM TIMER
INT 08 C - IRQ0 - SYSTEM TIMER
Desc:	generated 18.2 times per second by channel 0 of the 8254 system timer,
	  this interrupt is used to keep the time-of-day clock updated
Notes:	programs which need to be invoked regularly should use INT 1C unless
	  they need to reprogram the timer while still keeping the time-of-day
	  clock running at the proper rate
	default handler is at F000h:FEA5h in IBM PC and 100%-compatible BIOSes
	may be masked by setting bit 0 on I/O port 21h
SeeAlso: INT 1C,INT 4A"SYSTEM",INT 50"DESQview",INT 58"DoubleDOS",INT 70"IRQ8"
SeeAlso: INT 78"GO32",INT D8"Screen Thief",MEM 0040h:0040h,MEM 0040h:006Ch

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08 - INT 08 C - CPU-generated (80286+) - DOUBLE EXCEPTION DETECTED
INT 08 C - CPU-generated (80286+) - DOUBLE EXCEPTION DETECTED
Desc:	called when multiple exceptions occur on one instruction, or an
	  exception occurs in an exception handler
Notes:	called in protected mode if an interrupt above the defined limit of
	  the interrupt vector table occurs
	return address points at beginning of instruction with errors or the
	  beginning of the instruction which was about to execute when the
	  external interrupt caused the exception
	if an exception occurs in the double fault handler, the CPU goes into
	  SHUTDOWN mode (which circuitry in the PC/AT converts to a reset);
	  this "triple fault" is a faster way of returning to real mode on
	  many 80286 machines than the standard keyboard controller reset

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