Mohamed Mediouni 6

[email protected]

Mohamed Mediouni

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Interrupt Handling Interrupt is just a particular exception • Caught by kernel code • Dealt with prior to resuming user code • But hardware is independent of OS

1. Interrupt Occurs

Vector Table Vector1

2

Status Register

PSR

ISR NN ISR

.

.

.

.

.

.

IDT- Vector table

Driver is assigned interrupt by the PNP manager Driver registers with kernel it’s ISR When IRQ fires, IDT table links the IRQ to the ISR

• •

ISR code must set PIC IRQ mask handles PIC EOI

ISR

.

.

Lightweight code to quiet interrupt 3

.

IISR Kernel OAL

Except. Handler

.

Vector 0 Vector2

Vector N VectorN

  

Memory

Driver

2. Exception Handler fetchs Status register & 3. links IRQ to ISR based on IDT (registered ISR)

App

Memory

HW

1

None Mohamed Mediouni

2

App

2. Exception Handler fetchs Status register & 3. links IRQ to ISR

Driver registers IISR DLL with the Kernel with the call to LoadIntChainHandler()

Support for hardware IRQ sharing Distinct SYSINTR ID from same IRQ

Driver

1. Interrupt Occurs

4. ISR decodes IRQ from hardware, calls kernel to query IISRs in binding order

SYSINTR_CHAIN

PSR

SYSINTR_xx SYSINTR_NOP

4

3

NKCallIntChain(IRQ)

2

ISR

None

Higher Priority IRQs Enabled Mohamed Mediouni

HW

1

Kernel OAL

Except. Handler

IISRn IRQ go away

IISR2

IISR

IISR1

3

App

5. IISR scheduled code to service hardware and return value indicates status

6. IRQ go away

Driver

1. Interrupt Occurs

2. Exception Handler fetchs Status register & 3. links IRQ to ISR 4. ISR decodes IRQ, calls kernel to query IISRs

SYSINTR_CHAIN

IISR2

IISR

IISR1

IISRn

Except. Handler

SYSINTR_xx SYSINTR_NOP

PSR

2

4NKCallIntChain(IRQ)

3

ISR

Higher Priority IRQs Enabled ( Mohamed Mediouni

HW

None

6

Kernel OAL

5

4

App

6. IISR return value indicates status SYSINTR_CHAIN indicates IRQ not recognized OAL ISR translates IRQ to SYSINTR as before SYSINTR_NOP indicates IISR run-to-completion IISR must make IRQ go away! Other values indicate IISR owns interrupt OAL ISR code must set PIC IRQ mask

7. ISR handles PIC EOI and returns ID

Driver

1. Interrupt Occurs

2. Exception Handler fetchs Status register & 3. links IRQ to ISR 4. ISR decodes IRQ, calls kernel to query IISRs 5. IISRs service hardware and return status

SYSINTR_CHAIN

5

Except. Handler PSR

SYSINTR_xx SYSINTR_NOP

IISRn 6

Set Event

4

3

NKCallIntChain(IRQ)

7

SYSINTR_ID

ISR

Kernel OAL

1

IISR2

IISR

IISR1

2 Higher Priority IRQs Enabled Mohamed Mediouni

IRQ Masked

HW

None

5

App

6. IISR return value indicates status SYSINTR_CHAIN indicates IRQ not recognized OAL ISR translates IRQ to SYSINTR as before SYSINTR_NOP indicates IISR run-to-completion IISR must make IRQ go away! Other values indicate IISR owns interrupt OAL ISR code must set PIC IRQ mask

7. ISR handles PIC EOI and returns ID

IISR1

5

Except. Handler PSR

SYSINTR_xx SYSINTR_NOP

IISRn

8

6

Set Event

4

3

NKCallIntChain(IRQ)

7

SYSINTR_ID

ISR

Kernel OAL

1

IISR2

IISR

8. Kernel signals event, IST becomes runnable

SYSINTR_CHAIN

Driver

1. Interrupt Occurs

2. Exception Handler fetchs Status register & 3. links IRQ to ISR 4. ISR decodes IRQ, calls kernel to query IISRs 5. IISRs service hardware and return status

2 Higher Priority IRQs Enabled Mohamed Mediouni

IRQ Masked

HW

None

6

2. Exception Handler fetchs Status register & 3. links IRQ to ISR

App

4. ISR decodes IRQ, calls kernel to query

1. Interrupt Occurs

Driver

IISRs 5. IISRs service hardware and return status 6. IISR return value indicates status

8. Kernel signals event, IST becomes runnable 9. Scheduler runs the IST 10. IST runs and resets the IST interrupt

7. ISR handles PIC EOI and returns ID

Except. Handler PSR

4

3

NKCallIntChain(IRQ)

7

8

SYSINTR_ID

ISR

Kernel OAL

1

IISR

IISR1

11. IST Creates an event object associated with IISRn the logical 6 5 interrupt by calling CreateEvent Set function Event (as Event Source)

2 Higher Priority IRQs Enabled Mohamed Mediouni

IRQ Masked

HW

None

7

Fitting It All Together

Interrupt Occurs

Interrupt Handler calls registered ISR

ISR runs, tells kernel which event to signal

IST runs and resets the interrupt

Scheduler runs the IST

Kernel signals event, IST becomes runnable

Mohamed Mediouni

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Event-driven architecture IST as Event dispatcher –( JRE)

10

9

11

1

8 KERNEL: Set Event IST: registered within the Kernel 2. event fired

(JRE)

1. add listener

IST as source of events dispatches Event Object to Application Listener objects which invoke the event handler Mohamed Mediouni

Dispatcher

to IST as source of Events

3. Look up Handler

4. Send to Handler 9

Executing events Application Event handler IST (within JRE) KERNEL: Set Event

Events queue

Events dispatcher

Event handler

Interruptenqueue(event) Interruptenqueue(event)

dequeue() event

handle(event)

dequeue() event

Mohamed Mediouni

handle(event)

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4 Steps 1st step: Create sources of events (ex. two buttons)

2nd step: Add the sources (ex. buttons) to the frame 3rd step: Register listeners to the sources

4th step: Implement handler

Mohamed Mediouni

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public class TestActionEvent extends Jframe implements ActionListener { // 1st step: Create sources of events (two buttons) private JButton jbtOK = new Jbutton(“OK”); private JButton jbtCL = new Jbutton(“Cancel”); // Constructor public TestActionEvent () { setTitle(); Container cp = getContentPane(); cp.setLayout(new FlowLayout()); // 2nd step: Add the sources (buttons) to the frame cp.add(jbtOK); cp.add(jbtCL); // 3rd step: Register listeners to the sources; jbtOK.addActionListener(this); jbtCL.addActionListener(this);

}

Mohamed Mediouni

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// 4th step:implement handler public void actionPerformed(ActionEvent e) { if(e.getSource() == jbtOK) { System.out.println(“The OK button is clicked”); } if(e.getSource() == jbtCL) { System.out.println(“The Cancel button is clicked“); }// actionPerformed }

Test Application public static void main(String[] args) { TestActionEvent frame = new TestActionEvent(); frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE); frame.setSize(100,100); frame.setVisible(true); }//main }// class Mohamed Mediouni

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