scale.backend.sparc
Class AnnulMarker

java.lang.Object
  scale.backend.Instruction
      scale.backend.Marker
          scale.backend.sparc.AnnulMarker

All Implemented Interfaces:

java.lang.Cloneable

public class AnnulMarker
extends Marker

This class marks the effective position of an annulled instruction.

$Id: AnnulMarker.java,v 1.9 2005-03-24 13:56:52 burrill Exp $

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

An annulled instruction acts as if it is part of the true edge of a branch instruction. For analysis purposes, it must seem to exist on that edge. For example,

   sdivcc %l0,%l1,%l2
   bvs,a  .l1
   sethi  %hi(0x80000000),%l2
 .l1:
 

is equivalent to

   sdivcc %l0,%l1,%l2
   bvs,a  .l1
   nop
   ba  .l0
 .l1:
   sethi  %hi(0x80000000),%l2
 .l0:
 

In this example, the definition of register %l2 by the sethi must occur on one edge only or the definition of %l2 by the sdivcc instruction is not seen as needed and the sdivcc instruction will be removed by the register allocation pass.

Constructor Summary

AnnulMarker(SparcInstruction annulled)

Method Summary

void	assembler(Assembler asm, Emit emit) Insert the assembler representation of the instruction into the output stream.
void	specifyRegisterUsage(RegisterAllocator rs, int index, int strength) Specify the registers used by this instruction.
java.lang.String	toString()

Methods inherited from class scale.backend.Marker

getExecutionCycles, getOpcode, independent, instructionSize, isMarker, nullify, remapDestRegister, remapRegisters, remapSrcRegister

Methods inherited from class scale.backend.Instruction

canBeDeleted, clone, copy, defs, ehash, getBBID, getCopyDest, getCopySrc, getDestRegister, getFunctionalUnit, getLoopNumber, getNext, getPredicate, getPredicates, getSrcRegisters, getTag, isBranch, isCopy, isLabel, isLoad, isMandatory, 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, uses

Methods inherited from class java.lang.Object

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

Constructor Detail

AnnulMarker

public AnnulMarker(SparcInstruction annulled)

Method Detail

specifyRegisterUsage

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

Specify the registers used by this instruction.

Overrides:

specifyRegisterUsage in class Marker

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)

assembler

public void assembler(Assembler asm,
                      Emit emit)

Description copied from class: Marker

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

Overrides:

assembler in class Marker

toString

public java.lang.String toString()

Overrides:

toString in class Marker