Package mars.assembler

Class SymbolTable

java.lang.Object

mars.assembler.SymbolTable

public class SymbolTable
extends Object

A symbol table used by the assembler to map symbols to the corresponding addresses.

Author:

Jason Bumgarner & Jason Shrewsbury, June 2003

Constructor Summary

Constructors

Constructor	Description
SymbolTable(String filename)	Create a new empty symbol table corresponding to the given filename.

Method Summary

Modifier and Type	Method	Description
void	clear()	Clear all symbols from the table.
Symbol	defineSymbol(String identifier, int address, boolean isData)	Adds a Symbol object into the array of Symbols.
Symbol	defineSymbol(Symbol symbol)	Adds a Symbol object into the array of Symbols.
Integer	getAddress(String identifier)	Get the address associated with the given identifier.
Symbol[]	getAllSymbols()	Get all symbols in the table.
Symbol[]	getDataSymbols()	Get all symbols in the table which represent data.
String	getFilename()
int	getSize()	Get the count of entries currently in the table.
Symbol	getSymbol(String identifier)	Produce Symbol object from symbol table that corresponds to given String.
Symbol[]	getTextSymbols()	Get all symbols in the table which represent text.
void	realignSymbols(int currentAddress, int alignedAddress)
void	removeSymbol(String identifier)	Removes a symbol from the Symbol table.

Methods inherited from class java.lang.Object

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

Constructor Details

SymbolTable

public SymbolTable(String filename)

Create a new empty symbol table corresponding to the given filename.

Parameters:

filename - The name of the file this symbol table is associated with. Will be used only for output/display so it can be any descriptive string.

Method Details

getFilename

public String getFilename()

defineSymbol

public Symbol defineSymbol(String identifier,
 int address,
 boolean isData)

Adds a Symbol object into the array of Symbols.

Parameters:

identifier - The identifier representing the Symbol.

address - The address of the Symbol.

isData - The type of Symbol, true for data, false for text.

defineSymbol

public Symbol defineSymbol(Symbol symbol)

Adds a Symbol object into the array of Symbols.

Parameters:

symbol - The symbol to add.

removeSymbol

public void removeSymbol(String identifier)

Removes a symbol from the Symbol table. If not found, it does nothing. This will rarely happen (only when variable is declared .globl after already being defined in the local symbol table).

Parameters:

identifier - The identifier for the symbol to remove.

getAddress

public Integer getAddress(String identifier)

Get the address associated with the given identifier.

Parameters:

identifier - The identifier to search for.

Returns:

The memory address of the identifier given, or null if not found in symbol table.

getSymbol

public Symbol getSymbol(String identifier)

Produce Symbol object from symbol table that corresponds to given String.

Parameters:

identifier - The identifier to search for.

Returns:

Symbol object for requested target, null if not found in symbol table.

getDataSymbols

public Symbol[] getDataSymbols()

Get all symbols in the table which represent data.

Returns:

Array of data symbols.

getTextSymbols

public Symbol[] getTextSymbols()

Get all symbols in the table which represent text.

Returns:

Array of text symbols.

getAllSymbols

public Symbol[] getAllSymbols()

Get all symbols in the table.

Returns:

Array of symbols.

getSize

public int getSize()

Get the count of entries currently in the table.

Returns:

Number of symbol table entries.

clear

public void clear()

Clear all symbols from the table.

realignSymbols

public void realignSymbols(int currentAddress,
 int alignedAddress)