package vm

import "bytes"

import "github.com/lunixbochs/struc"
import "github.com/pkg/errors"

const InstructionBytes = 32

type Instruction struct {
	OpCode   OpCodeType
	Reserved [4]byte
	Operand1 Operand
	Operand2 Operand

	opHandler OpHandler `struc:"skip"`
}

func NewInstruction(byteCode []byte) (*Instruction, error) {
	instr := &Instruction{}

	reader := bytes.NewReader(byteCode)

	err := struc.Unpack(reader, instr)
	if err != nil {
		return nil, errors.Wrap(err, "Error decoding instruction")
	}

	return instr, nil
}