Source code of Windows XP (NT5)
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/*++
Copyright (c) 2000 Microsoft Corporation
Module Name:
picinit.c
Abstract:
This module implements pic initialization code.
Author:
Forrest Foltz (forrestf) 1-Dec-2000
Environment:
Kernel mode only.
Revision History:
--*/
#include "halcmn.h"
VOID
HalpInitialize8259Tables (
VOID
);
VOID
HalpInitializeIrqlTables (
VOID
);
VOID
HalpInitializePICs (
IN BOOLEAN EnableInterrupts
)
/*++
Routine Description:
This routine sends the 8259 PIC initialization commands and masks all
the interrupts on 8259s.
Parameters:
EnableInterupts - Indicates whether interrupts should be explicitly
enabled just before returning.
Return Value:
Nothing.
--*/
{
ULONG flags;
#if defined(PICACPI)
//
// Build the irq<->IRQL mapping tables
//
HalpInitialize8259Tables();
#else
//
// Build the vector <-> INTI tables
//
HalpInitializeIrqlTables();
#endif
flags = HalpDisableInterrupts();
//
// First, program the master pic with ICW1 through ICW4
//
WRITE_PORT_UCHAR(PIC1_PORT0,
ICW1_ICW +
ICW1_EDGE_TRIG +
ICW1_INTERVAL8 +
ICW1_CASCADE +
ICW1_ICW4_NEEDED);
WRITE_PORT_UCHAR(PIC1_PORT1,
PIC1_BASE);
WRITE_PORT_UCHAR(PIC1_PORT1,
1 << PIC_SLAVE_IRQ);
WRITE_PORT_UCHAR(PIC1_PORT1,
ICW4_NOT_SPEC_FULLY_NESTED +
ICW4_NON_BUF_MODE +
ICW4_NORM_EOI +
ICW4_8086_MODE);
//
// Mask all irqs on the master
//
WRITE_PORT_UCHAR(PIC1_PORT1,0xFF);
//
// Next, program the slave pic with ICW1 through ICW4
//
WRITE_PORT_UCHAR(PIC2_PORT0,
ICW1_ICW +
ICW1_EDGE_TRIG +
ICW1_INTERVAL8 +
ICW1_CASCADE +
ICW1_ICW4_NEEDED);
WRITE_PORT_UCHAR(PIC2_PORT1,
PIC2_BASE);
WRITE_PORT_UCHAR(PIC2_PORT1,
PIC_SLAVE_IRQ);
WRITE_PORT_UCHAR(PIC2_PORT1,
ICW4_NOT_SPEC_FULLY_NESTED +
ICW4_NON_BUF_MODE +
ICW4_NORM_EOI +
ICW4_8086_MODE);
//
// Mask all IRQs on the slave
//
WRITE_PORT_UCHAR(PIC2_PORT1,0xFF);
if (EnableInterrupts != FALSE) {
HalpEnableInterrupts();
} else {
HalpRestoreInterrupts(flags);
}
}