nachos.userprog
Class UThread

java.lang.Object
  |
  +--nachos.threads.KThread
        |
        +--nachos.userprog.UThread

public class UThread

extends KThread

A UThread is KThread that can execute user program code inside a user process, in addition to Nachos kernel code.

Field Summary

UserProcess	process The process this thread belongs to.
int[]	userRegisters Storage for the user register set.

Fields inherited from class nachos.threads.KThread

schedulingState

Constructor Summary

UThread(UserProcess process)
Allocate a new UThread.

Method Summary

protected void	restoreState() Restore state before receiving the processor again.
protected void	saveState() Save state before giving up the processor to another thread.

Methods inherited from class nachos.threads.KThread

compareTo, currentThread, finish, fork, getName, join, ready, selfTest, setName, setTarget, sleep, toString, yield

Methods inherited from class java.lang.Object

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

Field Detail

userRegisters

public int[] userRegisters

Storage for the user register set.

A thread capable of running user code actually has two sets of CPU registers: one for its state while executing user code, and one for its state while executing kernel code. While this thread is not running, its user state is stored here.

process

public UserProcess process

The process this thread belongs to.

Constructor Detail

UThread

public UThread(UserProcess process)

Allocate a new UThread.

Method Detail

saveState

protected void saveState()

Save state before giving up the processor to another thread.

Overrides:

saveState in class KThread

restoreState

protected void restoreState()

Restore state before receiving the processor again.

Overrides:

restoreState in class KThread