/*
    TMHal.h, Copyright  (c) by George Fankhauser,
    Swiss Federal Institute of Technology,
    Computer Engineering and Networks Laboratory.

    TOPSY -- A Teachable Operating System.
             Implementation of a tiny and simple
             micro kernel for teaching purposes.

    For further information, please visit http://www.tik.ee.ethz.ch/~topsy

    This software is provided under the terms of the GNU General Public Licence.

    A full copy of the GNU GPL is provided in the file COPYING found in the 
    development root of Topsy.
*/
/*
	
	Revision 1.4  1999/10/22 19:09:05  gfa
	*** empty log message ***

	Revision 1.3  1999/06/06 20:55:25  jeker
	putting everything together for Topsy 2.0

	Revision 1.2  1999/05/13 17:05:56  jeker
	Initial revision
	
*/

#ifndef _TMHAL_H_
#define _TMHAL_H_

#include "tm-include.h"
#include "Exception.h"

#include "Unix.h"

#define MAXNBOFEXCEPTIONS     NOFSIGNALS
#define MAXNBOFINTERRUPTS              0

/* THREADRETURNADDR is defined inside TMHal.h to allow portability.... :-) */
#define THREADRETURNADDR      4

// status register bits
#define STATUS_INT_ENABLE_KERNEL_PREV 0
#define STATUS_INT_ENABLE_USER_PREV 0

/* Processor dependent thread information */
typedef struct ProcContext_t {
	struct ucontext uc;
#ifdef sparc
	struct gwindows gwins;
#endif	
} ProcContext;

/* Saving and restoring current thread context (assembler procedures) */
void saveContext(ProcContextPtr contextPtr);
void restoreContext(ProcContextPtr contextPtr);

/* operations on the thread context are machine dependent and 
 * encapsulated in the following functions. On CISC machines
 * most of these ops must be implemented using the current SP of
 * the context.
 */
void tmSetReturnValue(ProcContextPtr contextPtr, Register value);
void tmSetStackPointer(ProcContextPtr contextPtr, Register value);
void tmSetReturnAddress(ProcContextPtr contextPtr, Register value);
void tmSetProgramCounter(ProcContextPtr contextPtr, Register value);
void tmSetStatusRegister(ProcContextPtr contextPtr, Register value);
void tmSetFramePointer(ProcContextPtr contextPtr, Register value);
void tmSetArgument0(ProcContextPtr contextPtr, Register value);
void tmSetArgument1(ProcContextPtr contextPtr, Register value);
void tmSetMachineDependentRegisters(ProcContextPtr contextPtr, AddressSpace space);

Register tmGetProgramCounter(ProcContextPtr contextPtr);
Register tmGetFaultingAddress(ProcContextPtr contextPtr);

void enableInterruptInContext( InterruptId intId, ProcContextPtr contextPtr);
void disableInterruptInContext( InterruptId intId, ProcContextPtr contextPtr);
void enableAllInterruptsInContext( ProcContextPtr contextPtr);

/* installs code by copying generalExceptionHandler()'s and 
 * UTLBMissHandler()'s code at certain mips specific addresses
 */
void tmInstallExceptionCode();

/* Syscall exception handler (set per default as exception handler) */
void syscallExceptionHandler(ThreadId threadId);

/* Hardware exception handler (set per default as exception handler) */
void hwExceptionHandler();

/* Automatic exit of a thread when stack underflow occurs */
void automaticThreadExit();
void endAutomaticThreadExit();  // label to derive the length of the exit code

void generalExceptionHandler();

void msgAdjust(ThreadPtr pFromOrToThread, Message *msg, Boolean ToKernel);

void powerSaver();

#endif