serp.bytecode
Class CmpInstruction

java.lang.Object
  serp.bytecode.Instruction
      serp.bytecode.TypedInstruction
          serp.bytecode.CmpInstruction

All Implemented Interfaces:

BCEntity, VisitAcceptor

public class CmpInstruction
extends TypedInstruction

An instruction comparing two stack values. Examples include lcmp, fcmpl, etc.

Author:

Abe White

Method Summary

void	acceptVisit(BCVisitor visit) Accept a visit from a BCVisitor, calling the appropriate methods to notify the visitor that it has entered this entity, and to provide it with the proper callbacks for each sub-entity owned by this one.
int	getLogicalStackChange() Return the logical number of stack positions changed by this instruction.
int	getNaNValue() Return the number that will be placed on the stack if this instruction is of type float or double and one of the operands is NaN.
int	getStackChange() Return the number of stack positions this instruction pushes or pops during its execution.
String	getTypeName() Return the type name for this instruction.
CmpInstruction	setNaNValue(int nan) Set the number that will be placed on the stack if this instruction is of type float or double and one of the operands is NaN.
TypedInstruction	setType(String type) Set the type of this instruction.

Methods inherited from class serp.bytecode.TypedInstruction

getType, getTypeBC, setType, setType

Methods inherited from class serp.bytecode.Instruction

equalsInstruction, getByteIndex, getClassLoader, getCode, getLineNumber, getName, getOpcode, getPool, getProject, isValid

Methods inherited from class java.lang.Object

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

Method Detail

getLogicalStackChange

public int getLogicalStackChange()

Description copied from class: Instruction

Return the logical number of stack positions changed by this instruction. In other words, ignore weirdness with longs and doubles taking two stack positions.

Overrides:

getLogicalStackChange in class Instruction

getStackChange

public int getStackChange()

Description copied from class: Instruction

Return the number of stack positions this instruction pushes or pops during its execution.

Overrides:

getStackChange in class Instruction

Returns:

0 if the stack is not affected by this instruction, a positive number if it pushes onto the stack, and a negative number if it pops from the stack

getTypeName

public String getTypeName()

Description copied from class: TypedInstruction

Return the type name for this instruction. If the type has not been set, this method will return null.

Specified by:

getTypeName in class TypedInstruction

setType

public TypedInstruction setType(String type)

Description copied from class: TypedInstruction

Set the type of this instruction. Types that have no direct support will be converted accordingly.

Specified by:

setType in class TypedInstruction

Returns:

this instruction, for method chaining

getNaNValue

public int getNaNValue()

Return the number that will be placed on the stack if this instruction is of type float or double and one of the operands is NaN. For FCMPG or DCMPG, this value will be 1; for FCMPL or DCMPL this value will be -1. For LCMP or if the type is unset, this value will be 0.

setNaNValue

public CmpInstruction setNaNValue(int nan)

Set the number that will be placed on the stack if this instruction is of type float or double and one of the operands is NaN. For FCMPG or DCMPG, this value should be 1; for FCMPL or DCMPL this value should be -1. For LCMP, this value should be 0.

Returns:

this instruction, for method chaining

acceptVisit

public void acceptVisit(BCVisitor visit)

Description copied from interface: VisitAcceptor

Accept a visit from a BCVisitor, calling the appropriate methods to notify the visitor that it has entered this entity, and to provide it with the proper callbacks for each sub-entity owned by this one.

Specified by:

acceptVisit in interface VisitAcceptor

Overrides:

acceptVisit in class Instruction