scale.backend.trips2
Class ConstantInstruction

java.lang.Object
  scale.backend.Instruction
      scale.backend.trips2.ConstantInstruction

All Implemented Interfaces:

java.lang.Cloneable

public class ConstantInstruction
extends Instruction

This class represents Trips non-branch instructions for generating large constants.

$Id: ConstantInstruction.java,v 1.17 2006-11-09 00:56:11 burrill Exp $

Copyright 2005 by the Scale Compiler Group,
Department of Computer Science
University of Massachusetts,
Amherst MA. 01003, USA
All Rights Reserved.

Field Summary

protected int	cons the contant value.
protected int	ra the ra register.
protected int	rb the rb register.

Constructor Summary

ConstantInstruction(int opcode)
Create a new NOP instruction in the C:0 format.

ConstantInstruction(int opcode, int ra, int cons)
Create a new Contant Trips instruction in the C:0 format.

ConstantInstruction(int opcode, int ra, int rb, int cons)
Create a new Contant Trips instruction in the C:1 format.

Method Summary

void	assembler(Assembler asm, Emit emit) Insert the assembler representation of the instruction into the output stream.
boolean	canBeDeleted(RegisterSet registers) Return true if the instruction can be deleted without changing program semantics.
static int	created() Return the number of instances of this class created.
boolean	defs(int register, RegisterSet registers) Return true if the instruction sets the register
int	getConst() Return the constant field.
int	getCopyDest() Return the source register of a copy instruction.
int	getCopySrc() Return the source register of a copy instruction.
int	getDestRegister() Return the destination register.
byte	getFormat() Return the instruction format.
int	getOpcode() Return the instruction opcode.
int	getRa() Return the ra field.
int	getRb() Return the rb field.
int[]	getSrcRegisters() This routine returns the source registers for an instruction.
boolean	independent(Instruction inst, RegisterSet registers) Return true if this instruction is independent of the specified instruction.
int	instructionSize() Return the number of bytes required for the TripsInstruction.
boolean	isCopy() Return true if the instruction copies a value from one register to another without modification.
void	nullify(RegisterSet rs) Mark the instruction so that it is not used.
void	remapDestRegister(int oldReg, int newReg) Map the registers defined in the instruction as destinations to the specified register.
void	remapRegisters(int[] map) Map the virtual registers referenced in the instruction to the specified real registers.
void	remapSrcRegister(int oldReg, int newReg) Map the registers used in the instruction as sources to the specified register.
void	specifyRegisterUsage(RegisterAllocator rs, int index, int strength) Specify the registers used by this instruction.
java.lang.String	toString()
boolean	uses(int register, RegisterSet registers) Return true if the instruction uses the register.

Methods inherited from class scale.backend.Instruction

clone, copy, ehash, getBBID, getExecutionCycles, getFunctionalUnit, getLoopNumber, getNext, getPredicate, getPredicates, getTag, isBranch, isLabel, isLoad, isMandatory, isMarker, isPhi, isPredicated, isPredicatedOnTrue, isPrefetch, isSpillInstruction, isSpillLoadPoint, isSpillStorePoint, isStore, markSpillInstruction, mods, nullified, numPredicates, removePredicates, setBBID, setLoopNumber, setMandatory, setNext, setPredicate, setPredicate, setPredicatedOnTrue, setPredicates, setsSpecialReg, setTag, specifyNotSpillLoadPoint, specifySpillStorePoint

Methods inherited from class java.lang.Object

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

Field Detail

ra

protected int ra

the ra register.

rb

protected int rb

the rb register.

cons

protected int cons

the contant value.

Constructor Detail

ConstantInstruction

public ConstantInstruction(int opcode,
                           int ra,
                           int rb,
                           int cons)

Create a new Contant Trips instruction in the C:1 format.

Parameters:

opcode - specifies the pseudo-operation

ra - specifies the destination register

rb - specifies the left argument register

cons - specifies the constant argument

See Also:

Trips2Machine.minSignedConst, Trips2Machine.maxSignedConst, Trips2Machine.maxUnsignedConst

ConstantInstruction

public ConstantInstruction(int opcode,
                           int ra,
                           int cons)

Create a new Contant Trips instruction in the C:0 format.

Parameters:

opcode - specifies the pseudo-operation

ra - specifies the destination register

cons - specifies the constant argument

See Also:

Trips2Machine.minSignedConst, Trips2Machine.maxSignedConst, Trips2Machine.maxUnsignedConst

ConstantInstruction

public ConstantInstruction(int opcode)

Create a new NOP instruction in the C:0 format.

Method Detail

created

public static int created()

Return the number of instances of this class created.

remapRegisters

public void remapRegisters(int[] map)

Description copied from class: Instruction

Map the virtual registers referenced in the instruction to the specified real registers. The mapping is specified using an array that is indexed by the virtual register to return the real register.

Specified by:

remapRegisters in class Instruction

Parameters:

map - maps from the virtual register to real register

remapSrcRegister

public void remapSrcRegister(int oldReg,
                             int newReg)

Map the registers used in the instruction as sources to the specified register. If the register is not used as a source register, no change is made.

Specified by:

remapSrcRegister in class Instruction

Parameters:

oldReg - is the previous source register

newReg - is the new source register

remapDestRegister

public void remapDestRegister(int oldReg,
                              int newReg)

Map the registers defined in the instruction as destinations to the specified register. If the register is not used as a destination register, no change is made.

Specified by:

remapDestRegister in class Instruction

Parameters:

oldReg - is the previous destination register

newReg - is the new destination register

getOpcode

public int getOpcode()

Return the instruction opcode.

Specified by:

getOpcode in class Instruction

getDestRegister

public int getDestRegister()

Return the destination register.

Overrides:

getDestRegister in class Instruction

getSrcRegisters

public int[] getSrcRegisters()

This routine returns the source registers for an instruction. Null is returned if there are no source registers.

Overrides:

getSrcRegisters in class Instruction

getFormat

public byte getFormat()

Return the instruction format.

getRa

public int getRa()

Return the ra field.

getRb

public int getRb()

Return the rb field.

getConst

public int getConst()

Return the constant field.

specifyRegisterUsage

public void specifyRegisterUsage(RegisterAllocator rs,
                                 int index,
                                 int strength)

Specify the registers used by this instruction.

Specified by:

specifyRegisterUsage in class Instruction

Parameters:

rs - is the register set in use

index - is an index associated with the instruction

strength - is the importance of the instruction

See Also:

RegisterAllocator.useRegister(int,int,int), RegisterAllocator.defRegister(int,int)

uses

public boolean uses(int register,
                    RegisterSet registers)

Return true if the instruction uses the register.

Overrides:

uses in class Instruction

defs

public boolean defs(int register,
                    RegisterSet registers)

Return true if the instruction sets the register

Overrides:

defs in class Instruction

independent

public boolean independent(Instruction inst,
                           RegisterSet registers)

Return true if this instruction is independent of the specified instruction. If instructions are independent, than one instruction can be moved before or after the other instruction without changing the semantics of the program.

Specified by:

independent in class Instruction

Parameters:

inst - is the specified instruction

instructionSize

public int instructionSize()

Return the number of bytes required for the TripsInstruction.

Specified by:

instructionSize in class Instruction

canBeDeleted

public boolean canBeDeleted(RegisterSet registers)

Return true if the instruction can be deleted without changing program semantics.

Overrides:

canBeDeleted in class Instruction

nullify

public void nullify(RegisterSet rs)

Mark the instruction so that it is not used.

Overrides:

nullify in class Instruction

isCopy

public boolean isCopy()

Return true if the instruction copies a value from one register to another without modification. Transfers between integer and floating point registers are not considered to be copy instructions.

Overrides:

isCopy in class Instruction

getCopySrc

public int getCopySrc()

Return the source register of a copy instruction.

Overrides:

getCopySrc in class Instruction

getCopyDest

public int getCopyDest()

Return the source register of a copy instruction.

Overrides:

getCopyDest in class Instruction

assembler

public void assembler(Assembler asm,
                      Emit emit)

Insert the assembler representation of the instruction into the output stream.

Specified by:

assembler in class Instruction

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object