avail/avail.interpreter.levelTwo/L1InstructionStepper

L1InstructionStepper

class L1InstructionStepper(val interpreter: Interpreter)

This class is used to simulate the effect of level one nybblecodes during execution of the L2_INTERPRET_LEVEL_ONE instruction, on behalf of an Interpreter.

Author

Mark van Gulik

Parameters

interpreter

The Interpreter on whose behalf to step through level one nybblecode instructions.

Constructors

L1InstructionStepper

fun L1InstructionStepper(interpreter: Interpreter)

Construct a new L1InstructionStepper.

Types

Companion

object Companion

Functions

fun pc(): Int

Get the current program counter.

pointerAt

fun pointerAt(index: Int): AvailObject

Read from the specified object register.

pointerAtPut

fun pointerAtPut(index: Int, value: A_BasicObject)

Write to the specified object register.

run

fun run(): StackReifier?

Run the current code until it reaches the end. Individual instructions, such as calls, may be subject to reification, which should cause a suitable A_Continuation to be reified. In addition, inter-nybblecode interrupts may also trigger reification, but they'll handle their own reification prior to returning here with a suitable StackReifier (to update and return again from here).

wipeRegisters

fun wipeRegisters()

Wipe out the existing register set for safety.

Properties

instructionDecoder

val instructionDecoder: CompiledCodeDescriptor.L1InstructionDecoder

The current position in the nybblecodes.

interpreter

val interpreter: Interpreter

The Interpreter on whose behalf to step level one nybblecodes.

pointers

var pointers: Array<AvailObject>

The registers that hold Avail objects.

stackp

var stackp: Int = 0

The current stack position as would be seen in a continuation.