nachos.vm
Class VMProcess

java.lang.Object
  nachos.userprog.UserProcess
      nachos.vm.VMProcess

Direct Known Subclasses:

NetProcess

public class VMProcess
extends UserProcess

A UserProcess that supports demand-paging.

Field Summary

Fields inherited from class nachos.userprog.UserProcess

coff, numPages, pageTable, stackPages

Constructor Summary

VMProcess()
Allocate a new process.

Method Summary

void	handleException(int cause) Handle a user exception.
protected boolean	loadSections() Initializes page tables for this process so that the executable can be demand-paged.
void	restoreState() Restore the state of this process after a context switch.
void	saveState() Save the state of this process in preparation for a context switch.
protected void	unloadSections() Release any resources allocated by loadSections().

Methods inherited from class nachos.userprog.UserProcess

execute, handleSyscall, initRegisters, newUserProcess, readVirtualMemory, readVirtualMemory, readVirtualMemoryString, writeVirtualMemory, writeVirtualMemory

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

VMProcess

public VMProcess()

Allocate a new process.

Method Detail

saveState

public void saveState()

Save the state of this process in preparation for a context switch. Called by UThread.saveState().

Overrides:

saveState in class UserProcess

restoreState

public void restoreState()

Restore the state of this process after a context switch. Called by UThread.restoreState().

Overrides:

restoreState in class UserProcess

loadSections

protected boolean loadSections()

Initializes page tables for this process so that the executable can be demand-paged.

Overrides:

loadSections in class UserProcess

Returns:

true if successful.

unloadSections

protected void unloadSections()

Release any resources allocated by loadSections().

Overrides:

unloadSections in class UserProcess

handleException

public void handleException(int cause)

Handle a user exception. Called by UserKernel.exceptionHandler(). The cause argument identifies which exception occurred; see the Processor.exceptionZZZ constants.

Overrides:

handleException in class UserProcess

Parameters:

cause - the user exception that occurred.