mars.mips.hardware
Class RegisterFile

java.lang.Object
  extended by mars.mips.hardware.RegisterFile

public class RegisterFile
extends Object

Represents the collection of MIPS registers.

Author:
Jason Bumgarner, Jason Shrewsbury

Field Summary
static int GLOBAL_POINTER_REGISTER
           
static int STACK_POINTER_REGISTER
           
 
Constructor Summary
RegisterFile()
           
 
Method Summary
static void addRegistersObserver(Observer observer)
          Each individual register is a separate object and Observable.
static void deleteRegistersObserver(Observer observer)
          Each individual register is a separate object and Observable.
static int getInitialProgramCounter()
          For returning the program counter's initial (reset) value.
static int getNumber(String n)
          For getting the number representation of the register.
static int getProgramCounter()
          For returning the program counters value.
static Register getProgramCounterRegister()
          Returns Register object for program counter.
static Register[] getRegisters()
          For returning the set of registers.
static Register getUserRegister(String Rname)
          Get register object corresponding to given name.
static int getValue(int num)
          Returns the value of the register who's number is num.
static void incrementPC()
          Method to increment the Program counter in the general case (not a jump or branch).
static void initializeProgramCounter(boolean startAtMain)
          Will initialize the Program Counter to either the default reset value, or the address associated with source program global label "main", if it exists as a text segment label and the global setting is set.
static void initializeProgramCounter(int value)
          For initializing the Program Counter.
static void resetRegisters()
          Method to reinitialize the values of the registers.
static int setProgramCounter(int value)
          For setting the Program Counter.
static void showRegisters()
          Method for displaying the register values for debugging.
static int updateRegister(int num, int val)
          This method updates the register value who's number is num.
static void updateRegister(String reg, int val)
          Sets the value of the register given to the value given.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

GLOBAL_POINTER_REGISTER

public static final int GLOBAL_POINTER_REGISTER
See Also:
Constant Field Values

STACK_POINTER_REGISTER

public static final int STACK_POINTER_REGISTER
See Also:
Constant Field Values
Constructor Detail

RegisterFile

public RegisterFile()
Method Detail

showRegisters

public static void showRegisters()
Method for displaying the register values for debugging.


updateRegister

public static int updateRegister(int num,
                                 int val)
This method updates the register value who's number is num. Also handles the lo and hi registers

Parameters:
num - Register to set the value of.
val - The desired value for the register.

updateRegister

public static void updateRegister(String reg,
                                  int val)
Sets the value of the register given to the value given.

Parameters:
reg - Name of register to set the value of.
val - The desired value for the register.

getValue

public static int getValue(int num)
Returns the value of the register who's number is num.

Parameters:
num - The register number.
Returns:
The value of the given register.

getNumber

public static int getNumber(String n)
For getting the number representation of the register.

Parameters:
n - The string formatted register name to look for.
Returns:
The number of the register represented by the string or -1 if no match.

getRegisters

public static Register[] getRegisters()
For returning the set of registers.

Returns:
The set of registers.

getUserRegister

public static Register getUserRegister(String Rname)
Get register object corresponding to given name. If no match, return null.

Parameters:
Rname - The register name, either in $0 or $zero format.
Returns:
The register object,or null if not found.

initializeProgramCounter

public static void initializeProgramCounter(int value)
For initializing the Program Counter. Do not use this to implement jumps and branches, as it will NOT record a backstep entry with the restore value. If you need backstepping capability, use setProgramCounter instead.

Parameters:
value - The value to set the Program Counter to.

initializeProgramCounter

public static void initializeProgramCounter(boolean startAtMain)
Will initialize the Program Counter to either the default reset value, or the address associated with source program global label "main", if it exists as a text segment label and the global setting is set.

Parameters:
startAtMain - If true, will set program counter to address of statement labeled 'main' (or other defined start label) if defined. If not defined, or if parameter false, will set program counter to default reset value.

setProgramCounter

public static int setProgramCounter(int value)
For setting the Program Counter. Note that ordinary PC update should be done using incrementPC() method. Use this only when processing jumps and branches.

Parameters:
value - The value to set the Program Counter to.
Returns:
previous PC value

getProgramCounter

public static int getProgramCounter()
For returning the program counters value.

Returns:
The program counters value as an int.

getProgramCounterRegister

public static Register getProgramCounterRegister()
Returns Register object for program counter. Use with caution.

Returns:
program counter's Register object.

getInitialProgramCounter

public static int getInitialProgramCounter()
For returning the program counter's initial (reset) value.

Returns:
The program counter's initial value

resetRegisters

public static void resetRegisters()
Method to reinitialize the values of the registers. NOTE: Should not be called from command-mode MARS because this this method uses global settings from the registry. Command-mode must operate using only the command switches, not registry settings. It can be called from tools running stand-alone, and this is done in AbstractMarsToolAndApplication.


incrementPC

public static void incrementPC()
Method to increment the Program counter in the general case (not a jump or branch).


addRegistersObserver

public static void addRegistersObserver(Observer observer)
Each individual register is a separate object and Observable. This handy method will add the given Observer to each one. Currently does not apply to Program Counter.


deleteRegistersObserver

public static void deleteRegistersObserver(Observer observer)
Each individual register is a separate object and Observable. This handy method will delete the given Observer from each one. Currently does not apply to Program Counter.