Package com.pnfsoftware.jeb.core.units.code.asm.simulator

Interface IInsnEmulator<T extends IInstructionOperand>

Type Parameters:

T - operand type

All Known Implementing Classes:

InsnEmulator

public interface IInsnEmulator<T extends IInstructionOperand>

High Level design for an instruction emulator: it indicates if the PC is updated (meaning a jump will be done, see getBranchType() for jump type) and is able to compute the result of the operation. Please note that the compute(byte[], long, int, IInstructionOperand[], IMachineContext) implementation is not guaranteed, plus it can depends on context (register values, memory access).

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static enum	IInsnEmulator.BranchType	Branch categories reported by an emulator.

Method Summary

Modifier and Type	Method	Description
Long	compute(byte[] code, long instructionAddress, int mode, T[] armOperands, IMachineContext context)	Compute the result of the instruction (ADD, SUB...).
IInsnEmulator.BranchType	getBranchType()	Return BranchType (JUMP or LINK).
boolean	isPCUpdated()	Indicate if the instruction can update the PC (by another address than the following one).

Method Details

isPCUpdated

boolean isPCUpdated()

Indicate if the instruction can update the PC (by another address than the following one).

Returns:

true if the instruction may update the program counter

compute

Long compute(byte[] code,
 long instructionAddress,
 int mode,
 T[] armOperands,
 IMachineContext context)
      throws ProcessorException

Compute the result of the instruction (ADD, SUB...). When the context is not provided or has missing entries, this method will return null as result or raise a ProcessorException. If this operation is not implemented, an UnsupportedOperationException will be raised.

Parameters:

code - instruction bytes

instructionAddress - instruction address

mode - processor mode

armOperands - instruction operands

context - optional machine context

Returns:

computed result, or null if it cannot be computed

Throws:

ProcessorException - if the result cannot be computed

getBranchType

IInsnEmulator.BranchType getBranchType()

Return BranchType (JUMP or LINK). See later if more is needed.

Returns:

branch type, or null if the instruction does not branch