diff --git a/Machines/Commodore/1540/Implementation/C1540.cpp b/Machines/Commodore/1540/Implementation/C1540.cpp
index 9a1d8ef95..ee7038f85 100644
--- a/Machines/Commodore/1540/Implementation/C1540.cpp
+++ b/Machines/Commodore/1540/Implementation/C1540.cpp
@@ -16,13 +16,19 @@
 
 using namespace Commodore::C1540;
 
-ROM::Request Machine::rom_request(Personality personality) {
+namespace {
+ROM::Name rom_name(Personality personality) {
 	switch(personality) {
 		default:
-		case Personality::C1540:	return ROM::Request(ROM::Name::Commodore1540);
-		case Personality::C1541:	return ROM::Request(ROM::Name::Commodore1541);
+		case Personality::C1540:	return ROM::Name::Commodore1540;
+		case Personality::C1541:	return ROM::Name::Commodore1541;
 	}
 }
+}
+
+ROM::Request Machine::rom_request(Personality personality) {
+	return ROM::Request(rom_name(personality));
+}
 
 MachineBase::MachineBase(Personality personality, const ROM::Map &roms) :
 		Storage::Disk::Controller(1000000),
@@ -30,34 +36,27 @@ MachineBase::MachineBase(Personality personality, const ROM::Map &roms) :
 		serial_port_VIA_port_handler_(serial_port_VIA_),
 		drive_VIA_(drive_VIA_port_handler_),
 		serial_port_VIA_(serial_port_VIA_port_handler_) {
-	// attach the serial port to its VIA and vice versa
+	// Attach the serial port to its VIA and vice versa.
 	serial_port_.set_serial_port_via(serial_port_VIA_port_handler_);
 	serial_port_VIA_port_handler_.set_serial_port(serial_port_);
 
-	// set this instance as the delegate to receive interrupt requests from both VIAs
+	// Set this instance as the delegate to receive interrupt requests from both VIAs.
 	serial_port_VIA_port_handler_.set_interrupt_delegate(this);
 	drive_VIA_port_handler_.set_interrupt_delegate(this);
 	drive_VIA_port_handler_.set_delegate(this);
 
-	// set a bit rate
+	// Set a bit rate.
 	set_expected_bit_length(Storage::Encodings::CommodoreGCR::length_of_a_bit_in_time_zone(3));
 
-	// attach the only drive there is
+	// Attach the only drive there is.
 	emplace_drive(1000000, 300, 2);
 	set_drive(1);
 
-	ROM::Name rom_name;
-	switch(personality) {
-		default:
-		case Personality::C1540:	rom_name = ROM::Name::Commodore1540;	break;
-		case Personality::C1541:	rom_name = ROM::Name::Commodore1541;	break;
-	}
-
-	auto rom = roms.find(rom_name);
+	const auto rom = roms.find(rom_name(personality));
 	if(rom == roms.end()) {
 		throw ROMMachine::Error::MissingROMs;
 	}
-	std::memcpy(rom_, roms.find(rom_name)->second.data(), std::min(sizeof(rom_), roms.find(rom_name)->second.size()));
+	std::memcpy(rom_, rom->second.data(), std::min(sizeof(rom_), rom->second.size()));
 }
 
 Machine::Machine(Personality personality, const ROM::Map &roms) :
@@ -242,7 +241,7 @@ void DriveVIA::set_port_output(MOS::MOS6522::Port port, uint8_t value, uint8_t)
 	if(port) {
 		if(previous_port_b_output_ != value) {
 			// record drive motor state
-			drive_motor_ = !!(value&4);
+			drive_motor_ = value&4;
 
 			// check for a head step
 			int step_difference = ((value&3) - (previous_port_b_output_&3))&3;
@@ -257,7 +256,7 @@ void DriveVIA::set_port_output(MOS::MOS6522::Port port, uint8_t value, uint8_t)
 			}
 
 			// post the LED status
-			if(observer_) observer_->set_led_status("Drive", !!(value&8));
+			if(observer_) observer_->set_led_status("Drive", value&8);
 
 			previous_port_b_output_ = value;
 		}
@@ -268,7 +267,7 @@ void DriveVIA::set_activity_observer(Activity::Observer *observer) {
 	observer_ = observer;
 	if(observer) {
 		observer->register_led("Drive");
-		observer->set_led_status("Drive", !!(previous_port_b_output_&8));
+		observer->set_led_status("Drive", previous_port_b_output_&8);
 	}
 }