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//+----------------------------------------------------------------------------
//
// File: interrupts.c
//
// Module:
//
// Synopsis:
//
// Created: sgasch 6 Jul 2003
//
//+----------------------------------------------------------------------------
#include "kernel.h"
#include "hal.h"
#include "rtl.h"
#include "interrupts.h"
IDT_ENTRY g_IDT[NUM_IDT_ENTRIES];
INTERRUPT_HANDLER g_InterruptHandlerTable[NUM_IDT_ENTRIES];
ULONG g_uInterruptsEnabled = 0;
void
HalEnableInterrupts(void)
{
g_uInterruptsEnabled++;
ASSERT(g_uInterruptsEnabled == 1);
__asm__ __volatile__ (
"sti"
);
}
void
HalDisableInterrupts(void)
{
g_uInterruptsEnabled--;
ASSERT(g_uInterruptsEnabled == 0);
__asm__ __volatile__ (
"cli"
);
}
//+----------------------------------------------------------------------------
//
// Function: DoNothing
//
// Synopsis: The default interrupt handler, do nothing
//
// Arguments: INTERRUPT_STATE *p
//
// Returns: void
//
//+----------------------------------------------------------------------------
void HalDoNothing(INTERRUPT_STATE *p)
{
;
}
//+----------------------------------------------------------------------------
//
// Function: InterruptSendIrqEoi
//
// Synopsis: Send Interrupt ReQuest End Of Interrupt to the PIC.
//
// Arguments: INTERRUPT_STATE *is
//
// Returns: void
//
//+----------------------------------------------------------------------------
void
HalInterruptSendIrqEoi(INTERRUPT_STATE *is)
{
ULONG uIrq;
BYTE bCommand;
BYTE *p = (BYTE *)0x000B8000;
*p = '3';
*(p + 1) = ' ';
if ((is->uIntNum >= FIRST_EXTERNAL_INT) &&
(is->uIntNum <= LAST_EXTERNAL_INT))
{
uIrq = (is->uIntNum - FIRST_EXTERNAL_INT);
ASSERT(uIrq >= 0);
ASSERT(uIrq <= 15);
bCommand = 0x60 | (uIrq & 0x7);
if (uIrq < 8)
{
// EOI to master PIC
out(0x20, bCommand);
HalIoDelay();
}
else
{
// EOI to slave PIC and cascade line EOI to master PIC
out(0xA0, bCommand);
out(0x20, 0x62);
HalIoDelay();
}
}
*p = '4';
*(p + 1) = ' ';
}
//+----------------------------------------------------------------------------
//
// Function: InterruptInitializeGate
//
// Synopsis: Initializes an interrupt gate with given handler address
// and descriptor privilege level.
//
// Arguments: IDT_ENTRY *pEntry,
// void *pPreamble,
// ULONG uDpl
//
// Returns: void
//
//+----------------------------------------------------------------------------
void
HalInterruptInitializeGate(IDT_ENTRY *pEntry,
void *pPreamble,
ULONG uDpl)
{
ULONG u = (ULONG)pPreamble;
pEntry->i.offsetLow = u & 0xffff;
pEntry->i.segmentSelector = (1<<3);
pEntry->i.reserved = 0;
pEntry->i.signature = 0x70; // == 01110000b
pEntry->i.dpl = uDpl;
pEntry->i.present = 1;
pEntry->i.offsetHigh = u >> 16;
}
//+----------------------------------------------------------------------------
//
// Function: InterruptInstallHandler
//
// Synopsis: Installs an interrupt handler routine for a given IRQ number
//
// Arguments: ULONG uInterruptNumber,
// INTERRUPT_HANDLER pHandler
//
// Returns: void
//
//+----------------------------------------------------------------------------
void
HalInterruptInstallHandler(ULONG uInterruptNumber,
INTERRUPT_HANDLER pHandler)
{
ASSERT(uInterruptNumber < ARRAY_LENGTH(g_InterruptHandlerTable));
g_InterruptHandlerTable[uInterruptNumber] = pHandler;
}
//+----------------------------------------------------------------------------
//
// Function: InterruptInitialize
//
// Synopsis: Initialize the interrupt system
//
// Arguments: void
//
// Returns: void
//
//+----------------------------------------------------------------------------
void
HalInitializeInterrupts(void)
{
ULONG uPreambleEntrySize = (ULONG)&HalInterruptHandlerPreambleAfter;
ULONG u;
ULONG uDpl;
USHORT uLimitAndBase[3];
BYTE *p;
//
// Determine the size of an interrupt preamble table entry.
//
uPreambleEntrySize -= (ULONG)&HalInterruptHandlerPreambleBefore;
//
// Set the base interrupt number for each PIC. See comments in
// intsupport.asm.
//
HalInterruptInitializePICs();
//
// Build interrupt descriptor table
//
for (u = 0, p = &HalInterruptHandlerPreamble;
u < ARRAY_LENGTH(g_IDT);
u++, p += uPreambleEntrySize)
{
uDpl = (u == 0x2E) ? USER_PRIVILEGE : KERNEL_PRIVILEGE;
HalInterruptInitializeGate(&(g_IDT[u]), p, uDpl);
HalInterruptInstallHandler(u, HalDoNothing);
}
//
// Install the IDT
//
u = (ULONG)&(g_IDT);
uLimitAndBase[0] = 8 * NUM_IDT_ENTRIES;
uLimitAndBase[1] = (USHORT)(u & 0xffff);
uLimitAndBase[2] = (USHORT)(u >> 16);
HalInterruptLoadIDTR((void *)uLimitAndBase);
//
// Install interrupt handlers
//
HalInterruptInstallHandler(IRQ0, HalTimerInt);
HalInterruptInstallHandler(IRQ1, HalKeyboardInt);
out(0x21, 0xFC); // turn on keyboard and timer
//
// Enable interrupts
//
HalEnableInterrupts();
}
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