christoph/lecture-operating-system-development
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implement exercise 04 interrupts

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This commit is contained in:
churl
2022-05-14 21:12:32 +02:00
parent deb0ebd8eb
commit 13df44fb6f
8 changed files with 208 additions and 120 deletions
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60
c_os/kernel/interrupts/PIC.cc
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@ -15,13 +15,11 @@
* Autor: Olaf Spinczyk, TU Dortmund *
*****************************************************************************/
#include "kernel/PIC.h"
#include "kernel/interrupts/PIC.h"
#include "kernel/IOport.h"
static IOport IMR1 (0x21); // interrupt mask register von PIC 1
static IOport IMR2 (0xa1); // interrupt mask register von PIC 2
static IOport IMR1(0x21); // interrupt mask register von PIC 1
static IOport IMR2(0xa1); // interrupt mask register von PIC 2
/*****************************************************************************
* Methode: PIC::allow *
@ -34,12 +32,24 @@ static IOport IMR2 (0xa1); // interrupt mask register von PIC 2
* Parameter: *
* irq: IRQ der erlaubt werden soll *
*****************************************************************************/
void PIC::allow (int irq) {
void PIC::allow(int irq) {
/* hier muss Code eingefuegt werden */
}
// NOTE: allow sets the bit to 0
unsigned char IMR;
unsigned char mask = ~(0x1 << (irq % 8));
if (irq < 8) {
// PIC 1
IMR = IMR1.inb(); // We don't want to change the other interrupt masks so use this as start value
IMR1.outb(IMR & mask);
} else {
// PIC 2
IMR = IMR2.inb();
IMR2.outb(IMR & mask);
}
}
/*****************************************************************************
* Methode: PIC::forbid *
@ -49,12 +59,24 @@ void PIC::allow (int irq) {
* Parameter: *
* interrupt: IRQ der maskiert werden soll *
*****************************************************************************/
void PIC::forbid (int irq) {
void PIC::forbid(int irq) {
/* hier muss Code eingefuegt werden */
}
// NOTE: forbid sets the bit to 1
unsigned char IMR;
unsigned char mask = 0x1 << (irq % 8);
if (irq < 8) {
// PIC 1
IMR = IMR1.inb(); // We don't want to change the other interrupt masks so use this as start value
IMR1.outb(IMR | mask);
} else {
// PIC 2
IMR = IMR2.inb();
IMR2.outb(IMR | mask);
}
}
/*****************************************************************************
* Methode: PIC::status *
@ -65,9 +87,23 @@ void PIC::forbid (int irq) {
* Parameter: *
* irq: IRQ dessen Status erfragt werden soll *
*****************************************************************************/
bool PIC::status (int irq) {
bool PIC::status(int irq) {
/* hier muss Code eingefuegt werden */
// TODO: How is IRQ2 handled (Slave PIC)?
// Does masking IRQ2 disable the whole slave?
unsigned char IMR;
if (irq < 8) {
// PIC 1
IMR = IMR1.inb();
} else {
// PIC 2
IMR = IMR2.inb();
}
// Use % 8 to account for two PICs
unsigned char mask = 0x1 << (irq % 8);
return IMR & mask;
}