Programmable Interrupt Controller

Functions
void	picInit (uint32_t interruptOffset)
	Initializes the programmable interrupt controller. More...
bool	picReserveIRQ (uint32_t irq, irq_callback callback)
	Assign a callback function to an IRQ. More...
void	picFreeIRQ (uint32_t irq)
	Release an IRQ. More...

Variables
uint32_t	irqBase = 0
irq_callback	irqTable [IRQ_COUNT]

IRQ Ports
#define	IRQ_PIT   0
#define	IRQ_KEYBOARD   1
#define	IRQ_SLAVE   2
#define	IRQ_COM2   3
#define	IRQ_COM1   4
#define	IRQ_LPT2   5
#define	IRQ_FLOPPY   6
#define	IRQ_LPT1   7
#define	IRQ_CMOS_CLOCK   8
#define	IRQ_PS2_MOUSE   12
#define	IRQ_FPU   13
#define	IRQ_ATA1   14
#define	IRQ_ATA2   15

Detailed Description

The Programmable Interrupt Controller (PIC) can be used to control hardware interrupts / IRQs. A device driver can set an IRQ handler through picReserveIRQ() and free it again with picFreeIRQ().

For more information about IRQs and Interrupts take a look at http://wiki.osdev.org/IRQ

Macro Definition Documentation

IRQ_ATA1

#define IRQ_ATA1   14

First ATA device (Hard disk or CD)

Definition at line 76 of file pic.h.

IRQ_ATA2

#define IRQ_ATA2   15

Second ATA device (Hard disk or CD)

Definition at line 77 of file pic.h.

IRQ_CMOS_CLOCK

#define IRQ_CMOS_CLOCK   8

The CMOS clock was just updated

Definition at line 73 of file pic.h.

IRQ_COM1

#define IRQ_COM1   4

The COM Port 1 received data

Definition at line 69 of file pic.h.

IRQ_COM2

#define IRQ_COM2   3

The COM Port 2 received data

Definition at line 68 of file pic.h.

IRQ_FLOPPY

#define IRQ_FLOPPY   6

The floppy driver has read some data

Definition at line 71 of file pic.h.

IRQ_FPU

#define IRQ_FPU   13

Not used in modern CPUs

Definition at line 75 of file pic.h.

IRQ_KEYBOARD

#define IRQ_KEYBOARD   1

A key was pressed on the Keyboard

Definition at line 66 of file pic.h.

IRQ_LPT1

#define IRQ_LPT1   7

The LPT Port 1 received data

Definition at line 72 of file pic.h.

IRQ_LPT2

#define IRQ_LPT2   5

The LPT Port 2 received data

Definition at line 70 of file pic.h.

IRQ_PIT

#define IRQ_PIT   0

Programmable Intervall Timer

Definition at line 65 of file pic.h.

IRQ_PS2_MOUSE

#define IRQ_PS2_MOUSE   12

The mouse was moved or clicked

Definition at line 74 of file pic.h.

IRQ_SLAVE

#define IRQ_SLAVE   2

The slave PIC received an IRQ

Definition at line 67 of file pic.h.

Function Documentation

picFreeIRQ()

void picFreeIRQ

(

uint32_t

irq

)

Release an IRQ.

Call this function if you do not longer need to listen for this IRQ.

Parameters

irq	The previously requested IRQ

Definition at line 186 of file pic.c.

picInit()

void picInit

(

uint32_t

interruptOffset

)

Initializes the programmable interrupt controller.

The PIC is required to handle hardware interrupts / IRQs. There are (theoretically) 16 hardware IRQs which can be mapped to interrupts.

Parameters

interruptOffset

The first interrupt which should handle the IRQs

Definition at line 103 of file pic.c.

picReserveIRQ()

bool picReserveIRQ	(	uint32_t	irq,
		irq_callback	callback
	)

Assign a callback function to an IRQ.

This function allows a device driver to get notified on an IRQ by executing a callback. The function can then handle the input and return the control back to the user program.

Parameters

irq	The irq which should be assigned
callback	The function which should be called on the irq

Returns

True, if the interrupt is not taken yet, false otherwise.

Definition at line 151 of file pic.c.

Variable Documentation

irqBase

uint32_t irqBase = 0

Definition at line 45 of file pic.c.

irqTable

irq_callback irqTable[IRQ_COUNT]

Definition at line 47 of file pic.c.