package vm

type opHandler func(*State, *Instruction)

var opHandlers = map[OpCodeType]opHandler{
	OpNoOp: (*State).handleNoOp,

	OpMove: (*State).handleMove,

	OpAdd:            (*State).handleAdd,
	OpSubtract:       (*State).handleSubtract,
	OpMultiply:       (*State).handleMultiply,
	OpDivideUnsigned: (*State).handleDivideUnsigned,
	OpDivideSigned:   (*State).handleDivideSigned,

	OpNot: (*State).handleNot,
	OpAnd: (*State).handleAnd,
	OpOr:  (*State).handleOr,
	OpXor: (*State).handleXor,

	OpShiftRight: (*State).handleShiftRight,
	OpShiftLeft:  (*State).handleShiftLeft,

	OpIsEqual:                      (*State).handleIsEqual,
	OpIsLessThanUnsigned:           (*State).handleIsLessThanUnsigned,
	OpIsLessThanSigned:             (*State).handleIsLessThanSigned,
	OpIsGreaterThanUnsigned:        (*State).handleIsGreaterThanUnsigned,
	OpIsGreaterThanSigned:          (*State).handleIsGreaterThanSigned,
	OpIsLessThanOrEqualUnsigned:    (*State).handleIsLessThanOrEqualUnsigned,
	OpIsLessThanOrEqualSigned:      (*State).handleIsLessThanOrEqualSigned,
	OpIsGreaterThanOrEqualUnsigned: (*State).handleIsGreaterThanOrEqualUnsigned,
	OpIsGreaterThanOrEqualSigned:   (*State).handleIsGreaterThanOrEqualSigned,

	OpJump:        (*State).handleJump,
	OpJumpIfTrue:  (*State).handleJumpIfTrue,
	OpJumpIfFalse: (*State).handleJumpIfFalse,

	OpCall:        (*State).handleCall,
	OpCallIfTrue:  (*State).handleCallIfTrue,
	OpCallIfFalse: (*State).handleCallIfFalse,

	OpReturn:        (*State).handleReturn,
	OpReturnIfTrue:  (*State).handleReturnIfTrue,
	OpReturnIfFalse: (*State).handleReturnIfFalse,
}

func (state *State) handleNoOp(instr *Instruction) {
}

func (state *State) handleMove(instr *Instruction) {
	in := state.readUnsigned(&instr.Operand2)
	state.writeUnsigned(&instr.Operand1, in)
}

func (state *State) handleAdd(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.writeUnsigned(&instr.Operand1, in1+in2)
}

func (state *State) handleSubtract(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.writeUnsigned(&instr.Operand1, in1-in2)
}

func (state *State) handleMultiply(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.writeUnsigned(&instr.Operand1, in1*in2)
}

func (state *State) handleDivideUnsigned(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.writeUnsigned(&instr.Operand1, in1/in2)
}

func (state *State) handleDivideSigned(instr *Instruction) {
	in1 := state.readSigned(&instr.Operand1)
	in2 := state.readSigned(&instr.Operand2)
	state.writeSigned(&instr.Operand1, in1/in2)
}

func (state *State) handleNot(instr *Instruction) {
	in := state.readUnsigned(&instr.Operand1)
	state.writeUnsigned(&instr.Operand1, ^in)
}

func (state *State) handleAnd(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.writeUnsigned(&instr.Operand1, in1&in2)
}

func (state *State) handleOr(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.writeUnsigned(&instr.Operand1, in1|in2)
}

func (state *State) handleXor(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.writeUnsigned(&instr.Operand1, in1^in2)
}

func (state *State) handleShiftRight(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.writeUnsigned(&instr.Operand1, in1>>in2)
}

func (state *State) handleShiftLeft(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.writeUnsigned(&instr.Operand1, in1<<in2)
}

func (state *State) handleIsEqual(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.comparisonResult = (in1 == in2)
}

func (state *State) handleIsLessThanUnsigned(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.comparisonResult = (in1 < in2)
}

func (state *State) handleIsLessThanSigned(instr *Instruction) {
	in1 := state.readSigned(&instr.Operand1)
	in2 := state.readSigned(&instr.Operand2)
	state.comparisonResult = (in1 < in2)
}

func (state *State) handleIsGreaterThanUnsigned(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.comparisonResult = (in1 > in2)
}

func (state *State) handleIsGreaterThanSigned(instr *Instruction) {
	in1 := state.readSigned(&instr.Operand1)
	in2 := state.readSigned(&instr.Operand2)
	state.comparisonResult = (in1 > in2)
}

func (state *State) handleIsLessThanOrEqualUnsigned(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.comparisonResult = (in1 <= in2)
}

func (state *State) handleIsLessThanOrEqualSigned(instr *Instruction) {
	in1 := state.readSigned(&instr.Operand1)
	in2 := state.readSigned(&instr.Operand2)
	state.comparisonResult = (in1 <= in2)
}

func (state *State) handleIsGreaterThanOrEqualUnsigned(instr *Instruction) {
	in1 := state.readUnsigned(&instr.Operand1)
	in2 := state.readUnsigned(&instr.Operand2)
	state.comparisonResult = (in1 >= in2)
}

func (state *State) handleIsGreaterThanOrEqualSigned(instr *Instruction) {
	in1 := state.readSigned(&instr.Operand1)
	in2 := state.readSigned(&instr.Operand2)
	state.comparisonResult = (in1 >= in2)
}

func (state *State) handleJump(instr *Instruction) {
	in := state.readSigned(&instr.Operand1)
	state.jump(in)
}

func (state *State) handleJumpIfTrue(instr *Instruction) {
	if state.comparisonResult == true {
		state.handleJump(instr)
	}
}

func (state *State) handleJumpIfFalse(instr *Instruction) {
	if state.comparisonResult == false {
		state.handleJump(instr)
	}
}

func (state *State) handleCall(instr *Instruction) {
	in := state.readSigned(&instr.Operand1)
	state.call(in)
}

func (state *State) handleCallIfTrue(instr *Instruction) {
	if state.comparisonResult == true {
		state.handleCall(instr)
	}
}

func (state *State) handleCallIfFalse(instr *Instruction) {
	if state.comparisonResult == false {
		state.handleCall(instr)
	}
}

func (state *State) handleReturn(instr *Instruction) {
	state.ret()
}

func (state *State) handleReturnIfTrue(instr *Instruction) {
	if state.comparisonResult == true {
		state.handleReturn(instr)
	}
}

func (state *State) handleReturnIfFalse(instr *Instruction) {
	if state.comparisonResult == false {
		state.handleReturn(instr)
	}
}