exception.cc File Reference

Entry point into the Nachos kernel from user programs. More...

#include "copyright.h"
#include "system.h"
#include "syscall.h"
#include "userthread.h"

Macros
#define	MAX_FILENAME_BUFFER   200

Functions
void	ExitThread (void *object)
void	copyStringFromMachine (int from, char *to, unsigned size)
void	copyMachineFromString (char *from, int to, unsigned size)
void	ProcedurePutInt (int n)
void	ProcedureGetInt (int *n)
unsigned int	SYScreateUserThread (void *f, void *arg)
	SYScreateUserThread Syscall function that create a UserThread (and the thread) More...
void *	SYSWaitForChildExited (unsigned int CID)
	SYSWaitForChildExited. More...
void	SYSWaitForAllChildExited ()
	SYSWaitForAllChildExited Call SYSWaitForChildExited on all child.
void	SYSExitThread (void *object)
	SYSExitThread Syscall function to exit a thread (Kill it) Function called at end of all thread if no return and/or ExitThread() More...
void	StartUserThread (int data)
	StartUserThread Init the NachOS thread. More...
int	SYSStopChild (unsigned int CID)
	UserThread::StopChild Put the thread in BLOCKED status. More...
int	SYSWakeUpChild (unsigned int CID)
	UserThread::WakeUpChild Put a thread in Ready status. More...
void	ExceptionHandler (ExceptionType which)
	ExceptionHandler Entry point into the Nachos kernel. Called when a user program is executing, and either does a syscall, or generates an addressing or arithmetic exception. More...

Detailed Description

Entry point into the Nachos kernel from user programs.

Author

Olivier Hureau, Hugo Feydel , Julien ALaimo

Copyright (c) 1992-1993 The Regents of the University of California. All rights reserved. See copyright.h for copyright notice and limitation of liability and disclaimer of warranty provisions. syscall – The user code explicitly requests to call a procedure Entry point into the Nachos kernel from user programs. There are two kinds of things that can cause control to transfer back to here from user code:

syscall – The user code explicitly requests to call a procedure in the Nachos kernel. Right now, the only function we support is "Halt".

exceptions – The user code does something that the CPU can't handle. For instance, accessing memory that doesn't exist, arithmetic errors, etc. Interrupts (which can also cause control to transfer from user code into the Nachos kernel) are handled elsewhere.

For now, this only handles the Halt() system call. Everything else core dumps. Copyright (c) 1992-1993 The Regents of the University of California.

Function Documentation

void copyMachineFromString	(	char *	from,
		int	to,
		unsigned	size
	)

copyMachineFromString Copy a string from Kernel to Mips

Parameters

void copyStringFromMachine	(	int	from,
		char *	to,
		unsigned	size
	)

copyStringFromMachine Copy a string from MIPS to Kernel

Parameters

from	: the Machine adresse where the string is
to	: the Kernel adresse where to copy the string
size	: the string's adresse

void ExceptionHandler

(

ExceptionType

which

)

ExceptionHandler Entry point into the Nachos kernel. Called when a user program is executing, and either does a syscall, or generates an addressing or arithmetic exception.

For system calls, the following is the calling convention:

system call code – r2 arg1 – r4 arg2 – r5 arg3 – r6 arg4 – r7

The result of the system call, if any, must be put back into r2.

And don't forget to increment the pc before returning. (Or else you'll loop making the same system call forever!

Parameters

which

is the kind of exception. The list of possible exceptions are in machine.h.

void ProcedureGetInt

(

int *

n

)

ProcedurePutInt Get the int that have been written int the input stream of the SynchConsole Be carefull the absolute value of the int must be lower than 10^10-1 Negative int is supported

Parameters

n	: The adress where the int will be written

void ProcedurePutInt

(

int

n

)

ProcedurePutInt Put an int in the SynchConsole current output stream Be carefull the absolute value of the int must be lower than 10^10-1 Negative int is supported

Parameters

n	: The int to be printed

void StartUserThread

(

int

data

)

StartUserThread Init the NachOS thread.

Parameters

data

unsigned int SYScreateUserThread	(	void *	f,
		void *	arg
	)

SYScreateUserThread Syscall function that create a UserThread (and the thread)

Parameters

f	The function where the thread will begin
arg	the adress of the argument needed by this function

Returns

The unsigned int TID

void SYSExitThread

(

void *

object

)

SYSExitThread Syscall function to exit a thread (Kill it) Function called at end of all thread if no return and/or ExitThread()

Parameters

object

int SYSStopChild

(

unsigned int

CID

)

UserThread::StopChild Put the thread in BLOCKED status.

Parameters

CID

Returns

0 if the child have been stoped, 1 if the child is currently stop, 2 if it's not a child's TID

void* SYSWaitForChildExited

(

unsigned int

CID

)

SYSWaitForChildExited.

Parameters

CID

Returns

the adress of the object returned

int SYSWakeUpChild

(

unsigned int

CID

)

UserThread::WakeUpChild Put a thread in Ready status.

Parameters

CID

Returns

0 if the child have been WakeUp, 1 if the child is currently Ready, 2 if it's not a child's TID