Function opcodeToAltStack

txscript/opcode.go:1202–1210

opcodeToAltStack removes the top item from the main data stack and pushes it onto the alternate data stack. Main data stack transformation: [... x1 x2 x3] -> [... x1 x2] Alt data stack transformation: [... y1 y2 y3] -> [... y1 y2 y3 x3]

(op *opcode, data []byte, vm *Engine)

// Main data stack transformation: [... x1 x2 x3] -> [... x1 x2]
// Alt data stack transformation:  [... y1 y2 y3] -> [... y1 y2 y3 x3]
func opcodeToAltStack(op *opcode, data []byte, vm *Engine) error {
	so, err := vm.dstack.PopByteArray()
	if err != nil {
		return err
	}
	vm.astack.PushByteArray(so)

	return nil
}

// opcodeFromAltStack removes the top item from the alternate data stack and
// pushes it onto the main data stack.