diff --git a/serial_darwin.go b/serial_darwin.go
index e30c1a4..393236d 100644
--- a/serial_darwin.go
+++ b/serial_darwin.go
@@ -11,48 +11,6 @@ import "syscall"
 const devFolder = "/dev"
 const regexFilter = "^(cu|tty)\\..*"
 
-// termios manipulation functions
-
-var baudrateMap = map[int]uint{
-	0:      syscall.B9600, // Default to 9600
-	50:     syscall.B50,
-	75:     syscall.B75,
-	110:    syscall.B110,
-	134:    syscall.B134,
-	150:    syscall.B150,
-	200:    syscall.B200,
-	300:    syscall.B300,
-	600:    syscall.B600,
-	1200:   syscall.B1200,
-	1800:   syscall.B1800,
-	2400:   syscall.B2400,
-	4800:   syscall.B4800,
-	9600:   syscall.B9600,
-	19200:  syscall.B19200,
-	38400:  syscall.B38400,
-	57600:  syscall.B57600,
-	115200: syscall.B115200,
-	230400: syscall.B230400,
-}
-
-var databitsMap = map[int]uint{
-	0: syscall.CS8, // Default to 8 bits
-	5: syscall.CS5,
-	6: syscall.CS6,
-	7: syscall.CS7,
-	8: syscall.CS8,
-}
-
-const tcCMSPAR uint = 0 // may be CMSPAR or PAREXT
-const tcIUCLC uint = 0
-
-const tcCCTS_OFLOW uint = 0x00010000
-const tcCRTS_IFLOW uint = 0x00020000
-
-const tcCRTSCTS uint = (tcCCTS_OFLOW | tcCRTS_IFLOW)
-
-// syscall wrappers
-
 //sys ioctl(fd int, req uint64, data uintptr) (err error)
 
 const ioctlTcgetattr = syscall.TIOCGETA
diff --git a/serial_darwin_386.go b/serial_darwin_386.go
index 43f0375..a1a6771 100644
--- a/serial_darwin_386.go
+++ b/serial_darwin_386.go
@@ -6,6 +6,44 @@
 
 package serial // import "go.bug.st/serial.v1"
 
-func termiosMask(data uint) uint32 {
-	return uint32(data)
+import "syscall"
+
+// termios manipulation functions
+
+var baudrateMap = map[int]uint32{
+	0:      syscall.B9600, // Default to 9600
+	50:     syscall.B50,
+	75:     syscall.B75,
+	110:    syscall.B110,
+	134:    syscall.B134,
+	150:    syscall.B150,
+	200:    syscall.B200,
+	300:    syscall.B300,
+	600:    syscall.B600,
+	1200:   syscall.B1200,
+	1800:   syscall.B1800,
+	2400:   syscall.B2400,
+	4800:   syscall.B4800,
+	9600:   syscall.B9600,
+	19200:  syscall.B19200,
+	38400:  syscall.B38400,
+	57600:  syscall.B57600,
+	115200: syscall.B115200,
+	230400: syscall.B230400,
 }
+
+var databitsMap = map[int]uint32{
+	0: syscall.CS8, // Default to 8 bits
+	5: syscall.CS5,
+	6: syscall.CS6,
+	7: syscall.CS7,
+	8: syscall.CS8,
+}
+
+const tcCMSPAR uint32 = 0 // may be CMSPAR or PAREXT
+const tcIUCLC uint32 = 0
+
+const tcCCTS_OFLOW uint32 = 0x00010000
+const tcCRTS_IFLOW uint32 = 0x00020000
+
+const tcCRTSCTS uint32 = (tcCCTS_OFLOW | tcCRTS_IFLOW)
diff --git a/serial_darwin_amd64.go b/serial_darwin_amd64.go
index 0e70ce5..b721d78 100644
--- a/serial_darwin_amd64.go
+++ b/serial_darwin_amd64.go
@@ -6,8 +6,44 @@
 
 package serial // import "go.bug.st/serial.v1"
 
+import "syscall"
+
 // termios manipulation functions
 
-func termiosMask(data uint) uint64 {
-	return uint64(data)
+var baudrateMap = map[int]uint64{
+	0:      syscall.B9600, // Default to 9600
+	50:     syscall.B50,
+	75:     syscall.B75,
+	110:    syscall.B110,
+	134:    syscall.B134,
+	150:    syscall.B150,
+	200:    syscall.B200,
+	300:    syscall.B300,
+	600:    syscall.B600,
+	1200:   syscall.B1200,
+	1800:   syscall.B1800,
+	2400:   syscall.B2400,
+	4800:   syscall.B4800,
+	9600:   syscall.B9600,
+	19200:  syscall.B19200,
+	38400:  syscall.B38400,
+	57600:  syscall.B57600,
+	115200: syscall.B115200,
+	230400: syscall.B230400,
 }
+
+var databitsMap = map[int]uint64{
+	0: syscall.CS8, // Default to 8 bits
+	5: syscall.CS5,
+	6: syscall.CS6,
+	7: syscall.CS7,
+	8: syscall.CS8,
+}
+
+const tcCMSPAR uint64 = 0 // may be CMSPAR or PAREXT
+const tcIUCLC uint64 = 0
+
+const tcCCTS_OFLOW uint64 = 0x00010000
+const tcCRTS_IFLOW uint64 = 0x00020000
+
+const tcCRTSCTS uint64 = (tcCCTS_OFLOW | tcCRTS_IFLOW)
diff --git a/serial_freebsd.go b/serial_freebsd.go
index 046c489..1e09349 100644
--- a/serial_freebsd.go
+++ b/serial_freebsd.go
@@ -13,7 +13,7 @@ const regexFilter = "^(cu|tty)\\..*"
 
 // termios manipulation functions
 
-var baudrateMap = map[int]uint{
+var baudrateMap = map[int]uint32{
 	0:      syscall.B9600, // Default to 9600
 	50:     syscall.B50,
 	75:     syscall.B75,
@@ -37,7 +37,7 @@ var baudrateMap = map[int]uint{
 	921600: syscall.B921600,
 }
 
-var databitsMap = map[int]uint{
+var databitsMap = map[int]uint32{
 	0: syscall.CS8, // Default to 8 bits
 	5: syscall.CS5,
 	6: syscall.CS6,
@@ -45,19 +45,13 @@ var databitsMap = map[int]uint{
 	8: syscall.CS8,
 }
 
-const tcCMSPAR uint = 0 // may be CMSPAR or PAREXT
-const tcIUCLC uint = 0
+const tcCMSPAR uint32 = 0 // may be CMSPAR or PAREXT
+const tcIUCLC uint32 = 0
 
-const tcCCTS_OFLOW uint = 0x00010000
-const tcCRTS_IFLOW uint = 0x00020000
+const tcCCTS_OFLOW uint32 = 0x00010000
+const tcCRTS_IFLOW uint32 = 0x00020000
 
-const tcCRTSCTS uint = tcCCTS_OFLOW
-
-func termiosMask(data uint) uint32 {
-	return uint32(data)
-}
-
-// syscall wrappers
+const tcCRTSCTS uint32 = tcCCTS_OFLOW
 
 //sys ioctl(fd int, req uint64, data uintptr) (err error)
 
diff --git a/serial_linux.go b/serial_linux.go
index 1490a5e..89f3aed 100644
--- a/serial_linux.go
+++ b/serial_linux.go
@@ -13,7 +13,7 @@ const regexFilter = "(ttyS|ttyUSB|ttyACM|ttyAMA|rfcomm|ttyO)[0-9]{1,3}"
 
 // termios manipulation functions
 
-var baudrateMap = map[int]uint{
+var baudrateMap = map[int]uint32{
 	0:       syscall.B9600, // Default to 9600
 	50:      syscall.B50,
 	75:      syscall.B75,
@@ -47,7 +47,7 @@ var baudrateMap = map[int]uint{
 	4000000: syscall.B4000000,
 }
 
-var databitsMap = map[int]uint{
+var databitsMap = map[int]uint32{
 	0: syscall.CS8, // Default to 8 bits
 	5: syscall.CS5,
 	6: syscall.CS6,
@@ -55,16 +55,10 @@ var databitsMap = map[int]uint{
 	8: syscall.CS8,
 }
 
-const tcCMSPAR uint = 0 // may be CMSPAR or PAREXT
+const tcCMSPAR uint32 = 0 // may be CMSPAR or PAREXT
 const tcIUCLC = syscall.IUCLC
 
-const tcCRTSCTS uint = 0x80000000
-
-func termiosMask(data uint) uint32 {
-	return uint32(data)
-}
-
-// syscall wrappers
+const tcCRTSCTS uint32 = 0x80000000
 
 //sys ioctl(fd int, req uint64, data uintptr) (err error)
 
diff --git a/serial_unix.go b/serial_unix.go
index c481ffb..b5cf703 100644
--- a/serial_unix.go
+++ b/serial_unix.go
@@ -148,38 +148,43 @@ func setTermSettingsBaudrate(speed int, settings *syscall.Termios) error {
 		return &PortError{code: InvalidSpeed}
 	}
 	// revert old baudrate
-	var BAUDMASK uint
 	for _, rate := range baudrateMap {
-		BAUDMASK |= rate
+		settings.Cflag &^= rate
 	}
-	settings.Cflag &= ^termiosMask(BAUDMASK)
 	// set new baudrate
-	settings.Cflag |= termiosMask(baudrate)
-	settings.Ispeed = termiosMask(baudrate)
-	settings.Ospeed = termiosMask(baudrate)
+	settings.Cflag |= baudrate
+	settings.Ispeed = baudrate
+	settings.Ospeed = baudrate
 	return nil
 }
 
 func setTermSettingsParity(parity Parity, settings *syscall.Termios) error {
 	switch parity {
 	case NoParity:
-		settings.Cflag &= ^termiosMask(syscall.PARENB | syscall.PARODD | tcCMSPAR)
-		settings.Iflag &= ^termiosMask(syscall.INPCK)
+		settings.Cflag &^= syscall.PARENB
+		settings.Cflag &^= syscall.PARODD
+		settings.Cflag &^= tcCMSPAR
+		settings.Iflag &^= syscall.INPCK
 	case OddParity:
-		settings.Cflag |= termiosMask(syscall.PARENB | syscall.PARODD)
-		settings.Cflag &= ^termiosMask(tcCMSPAR)
-		settings.Iflag |= termiosMask(syscall.INPCK)
+		settings.Cflag |= syscall.PARENB
+		settings.Cflag |= syscall.PARODD
+		settings.Cflag &^= tcCMSPAR
+		settings.Iflag |= syscall.INPCK
 	case EvenParity:
-		settings.Cflag &= ^termiosMask(syscall.PARODD | tcCMSPAR)
-		settings.Cflag |= termiosMask(syscall.PARENB)
-		settings.Iflag |= termiosMask(syscall.INPCK)
+		settings.Cflag |= syscall.PARENB
+		settings.Cflag &^= syscall.PARODD
+		settings.Cflag &^= tcCMSPAR
+		settings.Iflag |= syscall.INPCK
 	case MarkParity:
-		settings.Cflag |= termiosMask(syscall.PARENB | syscall.PARODD | tcCMSPAR)
-		settings.Iflag |= termiosMask(syscall.INPCK)
+		settings.Cflag |= syscall.PARENB
+		settings.Cflag |= syscall.PARODD
+		settings.Cflag |= tcCMSPAR
+		settings.Iflag |= syscall.INPCK
 	case SpaceParity:
-		settings.Cflag &= ^termiosMask(syscall.PARODD)
-		settings.Cflag |= termiosMask(syscall.PARENB | tcCMSPAR)
-		settings.Iflag |= termiosMask(syscall.INPCK)
+		settings.Cflag |= syscall.PARENB
+		settings.Cflag &^= syscall.PARODD
+		settings.Cflag |= tcCMSPAR
+		settings.Iflag |= syscall.INPCK
 	}
 	return nil
 }
@@ -189,40 +194,63 @@ func setTermSettingsDataBits(bits int, settings *syscall.Termios) error {
 	if !ok {
 		return &PortError{code: InvalidDataBits}
 	}
-	settings.Cflag &= ^termiosMask(syscall.CSIZE)
-	settings.Cflag |= termiosMask(databits)
+	// Remove previous databits setting
+	settings.Cflag &^= syscall.CSIZE
+	// Set requested databits
+	settings.Cflag |= databits
 	return nil
 }
 
 func setTermSettingsStopBits(bits StopBits, settings *syscall.Termios) error {
 	switch bits {
 	case OneStopBit:
-		settings.Cflag &= ^termiosMask(syscall.CSTOPB)
+		settings.Cflag &^= syscall.CSTOPB
 	case OnePointFiveStopBits, TwoStopBits:
-		settings.Cflag |= termiosMask(syscall.CSTOPB)
+		settings.Cflag |= syscall.CSTOPB
 	}
 	return nil
 }
 
 func setTermSettingsCtsRts(enable bool, settings *syscall.Termios) {
 	if enable {
-		settings.Cflag |= termiosMask(tcCRTSCTS)
+		settings.Cflag |= tcCRTSCTS
 	} else {
-		settings.Cflag &= ^termiosMask(tcCRTSCTS)
+		settings.Cflag &^= tcCRTSCTS
 	}
 }
 
 func setRawMode(settings *syscall.Termios) {
 	// Set local mode
-	settings.Cflag |= termiosMask(syscall.CREAD | syscall.CLOCAL)
+	settings.Cflag |= syscall.CREAD
+	settings.Cflag |= syscall.CLOCAL
 
 	// Set raw mode
-	settings.Lflag &= ^termiosMask(syscall.ICANON | syscall.ECHO | syscall.ECHOE | syscall.ECHOK |
-		syscall.ECHONL | syscall.ECHOCTL | syscall.ECHOPRT | syscall.ECHOKE | syscall.ISIG | syscall.IEXTEN)
-	settings.Iflag &= ^termiosMask(syscall.IXON | syscall.IXOFF | syscall.IXANY | syscall.INPCK |
-		syscall.IGNPAR | syscall.PARMRK | syscall.ISTRIP | syscall.IGNBRK | syscall.BRKINT | syscall.INLCR |
-		syscall.IGNCR | syscall.ICRNL | tcIUCLC)
-	settings.Oflag &= ^termiosMask(syscall.OPOST)
+	settings.Lflag &^= syscall.ICANON
+	settings.Lflag &^= syscall.ECHO
+	settings.Lflag &^= syscall.ECHOE
+	settings.Lflag &^= syscall.ECHOK
+	settings.Lflag &^= syscall.ECHONL
+	settings.Lflag &^= syscall.ECHOCTL
+	settings.Lflag &^= syscall.ECHOPRT
+	settings.Lflag &^= syscall.ECHOKE
+	settings.Lflag &^= syscall.ISIG
+	settings.Lflag &^= syscall.IEXTEN
+
+	settings.Iflag &^= syscall.IXON
+	settings.Iflag &^= syscall.IXOFF
+	settings.Iflag &^= syscall.IXANY
+	settings.Iflag &^= syscall.INPCK
+	settings.Iflag &^= syscall.IGNPAR
+	settings.Iflag &^= syscall.PARMRK
+	settings.Iflag &^= syscall.ISTRIP
+	settings.Iflag &^= syscall.IGNBRK
+	settings.Iflag &^= syscall.BRKINT
+	settings.Iflag &^= syscall.INLCR
+	settings.Iflag &^= syscall.IGNCR
+	settings.Iflag &^= syscall.ICRNL
+	settings.Iflag &^= tcIUCLC
+
+	settings.Oflag &^= syscall.OPOST
 
 	// Block reads until at least one char is available (no timeout)
 	settings.Cc[syscall.VMIN] = 1