Package 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 Details

    • 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