Intel 386

9-39
INTERRUPT CONTROL UNIT
supports INTERRUPT_ISR (parameter is ignored).
Protected mode supports both.
Returns:Error Code
E_INVALID_VECTOR -- An IRQ of greater than 15 was passed
E_BADVECTOR -- IRQ is used for cascading to a slave interrupt
controller
E_OK -- Initialized OK, No error.
Assumptions:
Compiler supports far and interrupt keywords
ICU must be configured before this function is call for it to
operate properly
_IRQ_SlaveBase_,_IRQ_MstrBase_,_CascadeBits_ are set before function
is called. These are initialized in the InitICU functions supplied
in this source.
Syntax:
int error_code;
error_code = SetIRQVector(wdtISR,
15, // Slave IR#’s are offset by 8 in
// Vector Table
INTERRUPT_ISR);
Real/Protected Mode
No changes required. Uses SetInterruptVector which is mode
dependant (separate source)
*****************************************************************************/
int SetIRQVector( void (far interrupt *IntrProc)(void), int IRQ, int IntrType)
{
int Vector;
if(IRQ > 15) return E_INVALID_VECTOR;
if(IRQ > 7) // Get Vector from Slave
Vector = _IRQ_SlaveBase_ + IRQ - 8;
else // From Master
{
if((1 << IRQ) & _CascadeBits_) return E_BADVECTOR;
Vector = _IRQ_MstrBase_ + IRQ;
}
SetInterruptVector(IntrProc, Vector, IntrType);