Make use of C++ standard library

.gitignore

@@ -2,4 +2,10 @@
 Release
 Debug
 *.componentinfo.xml
-avrdude.bat
+*.elf
+*.o
+*.hex
+*.srec
+*.eeprom
+*.lss
+*.map

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2019 BlackMark
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is furnished
+to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice (including the next
+paragraph) shall be included in all copies or substantial portions of the
+Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
+OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
+OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

config.hpp

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <stdint.h>
+#include <cstdint>
 
 namespace uart {
 
@@ -27,17 +27,17 @@ namespace detail {
 
 template <DataBits dataBits>
 struct choose_data_type {
-	using type = uint8_t;
+	using type = std::uint8_t;
 };
 
 template <>
 struct choose_data_type<DataBits::NINE> {
-	using type = uint16_t;
+	using type = std::uint16_t;
 };
 
 } // namespace detail
 
-template <uint32_t baudRate = 9600, DataBits dataBits = DataBits::EIGHT, Parity parity = Parity::NONE,
+template <std::uint32_t baudRate = 9600, DataBits dataBits = DataBits::EIGHT, Parity parity = Parity::NONE,
           StopBits stopBits = StopBits::ONE>
 struct Config {
 	static constexpr auto BAUD_RATE = baudRate;

hardware.hpp

@@ -2,15 +2,13 @@
 
 #include "../clock.hpp"
 
-#include <stdint.h>
+#include <cmath>
-
+#include <cstdint>
-#define FORCE_INLINE __attribute__((always_inline))
 
 namespace uart {
 
 enum class Mode {
 	ASYNCHRONOUS,
-	ASYNCHRONOUS_2X,
 	SYNCHRONOUS_MASTER,
 	SYNCHRONOUS_SLAVE,
 	SPI,
@@ -23,105 +21,160 @@ enum class Driven {
 
 namespace detail {
 
-template <class Registers, typename CtrlFlagsA, typename CtrlFlagsB, typename CtrlFlagsC, class cfg, Mode mode,
+using reg_ptr_t = volatile std::uint8_t *;
-          Driven driven>
+
+template <std::uintptr_t Address>
+static inline reg_ptr_t getRegPtr()
+{
+	return reinterpret_cast<reg_ptr_t>(Address);
+}
+
+template <typename data_t, std::uint8_t Size>
+struct RingBuffer {
+	std::uint8_t head;
+	std::uint8_t tail;
+	data_t buf[Size];
+};
+
+template <class Registers, typename CtrlFlagsA, typename CtrlFlagsB, typename CtrlFlagsC, class cfg, Driven driven,
+          Mode mode>
 class Hardware {
   public:
-	static void init() FORCE_INLINE
+	[[gnu::always_inline]] static void init()
 	{
-		constexpr auto baudVal = calcBaud();
+		constexpr auto AbsDoubleError = std::fabs(calcBaudError<true>());
+		constexpr auto AbsNormalError = std::fabs(calcBaudError<false>());
+		static_assert(AbsDoubleError <= 3.0 || AbsNormalError <= 3.0, "Baud rate error over 3%, probably unusable");
 
-		*Registers::BAUD_REG_H = static_cast<uint8_t>(baudVal >> 8);
+		constexpr auto UseDoubleSpeed = (AbsDoubleError < AbsNormalError);
-		*Registers::BAUD_REG_L = static_cast<uint8_t>(baudVal);
+		constexpr auto BaudVal = calcBaudVal<UseDoubleSpeed>();
 
-		constexpr auto dataBitsVal = calcDataBits();
+		*getRegPtr<Registers::BAUD_REG_H_ADDR>() = static_cast<std::uint8_t>(BaudVal >> 8);
-		constexpr auto parityVal = calcParity();
+		*getRegPtr<Registers::BAUD_REG_L_ADDR>() = static_cast<std::uint8_t>(BaudVal);
-		constexpr auto stopBitsVal = calcStopBits();
-		constexpr auto modeVal = calcMode();
-		constexpr auto enableRx = calcRxState<true>();
-		constexpr auto enableTx = calcTxState<true>();
-		constexpr auto interruptVal = calcInterrupt();
 
-		constexpr uint8_t controlRegB = dataBitsVal.regBVal | enableRx | enableTx | interruptVal;
+		constexpr auto DataBitsValues = calcDataBits();
-		constexpr uint8_t controlRegC = dataBitsVal.regCVal | parityVal | stopBitsVal | modeVal;
+		constexpr auto ParityVal = calcParity();
+		constexpr auto StopBitsVal = calcStopBits();
+		constexpr auto ModeVal = calcMode();
+		constexpr auto EnableRx = calcRxState<true>();
+		constexpr auto EnableTx = calcTxState<true>();
+		constexpr auto InterruptVal = calcInterrupt();
 
-		*Registers::CTRL_STAT_REG_B = controlRegB;
+		constexpr std::uint8_t ControlRegB = DataBitsValues.regBVal | EnableRx | EnableTx | InterruptVal;
-		*Registers::CTRL_STAT_REG_C = controlRegC;
+		constexpr std::uint8_t ControlRegC = DataBitsValues.regCVal | ParityVal | StopBitsVal | ModeVal;
+
+		auto ctrlStatRegA = getRegPtr<Registers::CTRL_STAT_REG_A_ADDR>();
+
+		if constexpr (UseDoubleSpeed)
+			*ctrlStatRegA = *ctrlStatRegA | (1 << CtrlFlagsA::SPEED_2X);
+		else
+			*ctrlStatRegA = *ctrlStatRegA & ~(1 << CtrlFlagsA::SPEED_2X);
+
+		*getRegPtr<Registers::CTRL_STAT_REG_B_ADDR>() = ControlRegB;
+		*getRegPtr<Registers::CTRL_STAT_REG_C_ADDR>() = ControlRegC;
 	}
 
-	static bool rxByteBlocking(typename cfg::data_t &byte) FORCE_INLINE
+	[[gnu::always_inline]] static bool rxByteBlocking(typename cfg::data_t &byte)
 	{
-		if (*Registers::CTRL_STAT_REG_A & (1 << CtrlFlagsA::RECEIVE_COMPLETE)) {
+		if (*getRegPtr<Registers::CTRL_STAT_REG_A_ADDR>() & (1 << CtrlFlagsA::RECEIVE_COMPLETE)) {
-			byte = *Registers::IO_REG;
+			byte = *getRegPtr<Registers::IO_REG_ADDR>();
 			return true;
 		}
 
 		return false;
 	}
 
-	static typename cfg::data_t rxByteInterrupt() FORCE_INLINE
+	[[gnu::always_inline]] static typename cfg::data_t rxByteInterrupt()
 	{
-		return *Registers::IO_REG;
+		return *getRegPtr<Registers::IO_REG_ADDR>();
 	}
 
-	static bool txEmpty() FORCE_INLINE
+	[[gnu::always_inline]] static bool txEmpty()
 	{
-		return *Registers::CTRL_STAT_REG_A & (1 << CtrlFlagsA::DATA_REG_EMPTY);
+		return *getRegPtr<Registers::CTRL_STAT_REG_A_ADDR>() & (1 << CtrlFlagsA::DATA_REG_EMPTY);
 	}
 
-	static bool txComplete() FORCE_INLINE
+	[[gnu::always_inline]] static bool txComplete()
 	{
-		return *Registers::CTRL_STAT_REG_A & (1 << CtrlFlagsA::TRANSMIT_COMPLETE);
+		return *getRegPtr<Registers::CTRL_STAT_REG_A_ADDR>() & (1 << CtrlFlagsA::TRANSMIT_COMPLETE);
 	}
 
-	static void clearTxComplete() FORCE_INLINE
+	[[gnu::always_inline]] static void clearTxComplete()
 	{
-		*Registers::CTRL_STAT_REG_A |= (1 << CtrlFlagsA::TRANSMIT_COMPLETE);
+		*getRegPtr<Registers::CTRL_STAT_REG_A_ADDR>() |= (1 << CtrlFlagsA::TRANSMIT_COMPLETE);
 	}
 
-	static void txByteBlocking(const typename cfg::data_t &byte) FORCE_INLINE
+	[[gnu::always_inline]] static void txByteBlocking(const typename cfg::data_t &byte)
 	{
 		while (!txEmpty())
 			;
 
-		*Registers::IO_REG = byte;
+		*getRegPtr<Registers::IO_REG_ADDR>() = byte;
 	}
 
-	static void txByteInterrupt(volatile const typename cfg::data_t &byte) FORCE_INLINE
+	[[gnu::always_inline]] static void txByteInterrupt(volatile const typename cfg::data_t &byte)
 	{
-		*Registers::IO_REG = byte;
+		*getRegPtr<Registers::IO_REG_ADDR>() = byte;
 	}
 
-	static bool peekBlocking() FORCE_INLINE
+	[[gnu::always_inline]] static bool peekBlocking()
 	{
-		if (*Registers::CTRL_STAT_REG_A & (1 << CtrlFlagsA::RECEIVE_COMPLETE)) {
+		if (*getRegPtr<Registers::CTRL_STAT_REG_A_ADDR>() & (1 << CtrlFlagsA::RECEIVE_COMPLETE)) {
 			return true;
 		}
 
 		return false;
 	}
 
-	static void enableDataRegEmptyInt() FORCE_INLINE
+	[[gnu::always_inline]] static void enableDataRegEmptyInt()
 	{
-		*Registers::CTRL_STAT_REG_B |= (1 << CtrlFlagsB::DATA_REG_EMPTY_INT_ENABLE);
+		auto ctrlStatRegB = getRegPtr<Registers::CTRL_STAT_REG_B_ADDR>();
+		*ctrlStatRegB = *ctrlStatRegB | (1 << CtrlFlagsB::DATA_REG_EMPTY_INT_ENABLE);
 	}
 
-	static void disableDataRegEmptyInt() FORCE_INLINE
+	[[gnu::always_inline]] static void disableDataRegEmptyInt()
 	{
-		*Registers::CTRL_STAT_REG_B &= ~(1 << CtrlFlagsB::DATA_REG_EMPTY_INT_ENABLE);
+		auto ctrlStatRegB = getRegPtr<Registers::CTRL_STAT_REG_B_ADDR>();
+		*ctrlStatRegB = *ctrlStatRegB & ~(1 << CtrlFlagsB::DATA_REG_EMPTY_INT_ENABLE);
 	}
 
   private:
 	struct DataBitsVal {
-		uint8_t regCVal = 0;
+		std::uint8_t regCVal = 0;
-		uint8_t regBVal = 0;
+		std::uint8_t regBVal = 0;
 	};
 
-	static constexpr auto calcBaud()
+	template <bool DoubleSpeed = true>
+	static constexpr auto calcBaudVal()
 	{
-		// The actual formula is (F_CPU / (16 * baudRate)) - 1, but this one has the advantage of rounding correctly
+		if constexpr (DoubleSpeed) {
-		constexpr auto baudVal = (F_CPU + 8 * cfg::BAUD_RATE) / (16 * cfg::BAUD_RATE) - 1;
+			constexpr auto BaudVal = static_cast<std::uint16_t>(round(F_CPU / (8.0 * cfg::BAUD_RATE) - 1));
-		return baudVal;
+			return BaudVal;
+		}
+
+		constexpr auto BaudVal = static_cast<std::uint16_t>(round(F_CPU / (16.0 * cfg::BAUD_RATE) - 1));
+		return BaudVal;
+	}
+
+	template <std::uint16_t BaudVal, bool DoubleSpeed = true>
+	static constexpr auto calcBaudRate()
+	{
+		if constexpr (DoubleSpeed) {
+			constexpr auto BaudRate = static_cast<std::uint32_t>(round(F_CPU / (8.0 * (BaudVal + 1))));
+			return BaudRate;
+		}
+
+		constexpr auto BaudRate = static_cast<std::uint32_t>(round(F_CPU / (16.0 * (BaudVal + 1))));
+		return BaudRate;
+	}
+
+	template <bool DoubleSpeed = true>
+	static constexpr auto calcBaudError()
+	{
+		constexpr auto BaudVal = calcBaudVal<DoubleSpeed>();
+		constexpr auto ClosestBaudRate = calcBaudRate<BaudVal, DoubleSpeed>();
+		constexpr auto BaudError = (static_cast<double>(ClosestBaudRate) / cfg::BAUD_RATE - 1) * 100;
+		return BaudError;
 	}
 
 	static constexpr auto calcDataBits()
@@ -152,7 +205,7 @@ class Hardware {
 
 	static constexpr auto calcParity()
 	{
-		uint8_t parityVal = 0;
+		std::uint8_t parityVal = 0;
 
 		if (cfg::PARITY == Parity::EVEN)
 			parityVal = (1 << CtrlFlagsC::PARITY_MODE_1);
@@ -164,7 +217,7 @@ class Hardware {
 
 	static constexpr auto calcStopBits()
 	{
-		uint8_t stopBitsVal = 0;
+		std::uint8_t stopBitsVal = 0;
 
 		if (cfg::STOP_BITS == StopBits::TWO)
 			stopBitsVal = (1 << CtrlFlagsC::STOP_BIT_SEL);
@@ -176,7 +229,7 @@ class Hardware {
 	{
 		static_assert(mode != Mode::SPI, "SPI mode can not be used with uart");
 
-		uint8_t modeVal = 0;
+		std::uint8_t modeVal = 0;
 
 		if (mode == Mode::SYNCHRONOUS_MASTER || mode == Mode::SYNCHRONOUS_SLAVE) {
 			modeVal = (1 << CtrlFlagsC::MODE_SEL_0);
@@ -185,23 +238,23 @@ class Hardware {
 		return modeVal;
 	}
 
-	template <bool enable>
+	template <bool Enable>
 	static constexpr auto calcRxState()
 	{
-		uint8_t enableVal = 0;
+		std::uint8_t enableVal = 0;
 
-		if (enable)
+		if (Enable)
 			enableVal = (1 << CtrlFlagsB::RX_ENABLE);
 
 		return enableVal;
 	}
 
-	template <bool enable>
+	template <bool Enable>
 	static constexpr auto calcTxState()
 	{
-		uint8_t enableVal = 0;
+		std::uint8_t enableVal = 0;
 
-		if (enable)
+		if (Enable)
 			enableVal = (1 << CtrlFlagsB::TX_ENABLE);
 
 		return enableVal;
@@ -209,24 +262,162 @@ class Hardware {
 
 	static constexpr auto calcInterrupt()
 	{
-		uint8_t interruptVal = 0;
+		std::uint8_t interruptVal = 0;
 
 		if (driven == Driven::INTERRUPT)
-			interruptVal |= (1 << CtrlFlagsB::DATA_REG_EMPTY_INT_ENABLE) | (1 << CtrlFlagsB::RX_INT_ENABLE);
+			interruptVal = (1 << CtrlFlagsB::RX_INT_ENABLE);
 
 		return interruptVal;
 	}
 };
 
-template <typename data_t, uint8_t Size>
+template <class Registers, typename CtrlFlagsA, typename CtrlFlagsB, typename CtrlFlagsC, class cfg, Mode mode>
-struct RingBuffer {
+class BlockingHardware {
-	uint8_t head;
+  public:
-	uint8_t tail;
+	using data_t = typename cfg::data_t;
-	data_t buf[Size];
+	static constexpr auto DATA_BITS = cfg::DATA_BITS;
+
+	[[gnu::always_inline]] static void init()
+	{
+		HardwareImpl::init();
+	}
+
+	[[gnu::always_inline]] static void txByte(const data_t &byte)
+	{
+		HardwareImpl::txByteBlocking(byte);
+	}
+
+	[[gnu::always_inline]] static bool rxByte(data_t &byte)
+	{
+		return HardwareImpl::rxByteBlocking(byte);
+	}
+
+	[[gnu::always_inline]] static bool peek(data_t &)
+	{
+		static_assert(util::always_false_v<data_t>, "Peek with data is not supported in blocking mode");
+		return false;
+	}
+
+	[[gnu::always_inline]] static bool peek()
+	{
+		return HardwareImpl::peekBlocking();
+	}
+
+	[[gnu::always_inline]] static void flushTx()
+	{
+		while (!HardwareImpl::txEmpty())
+			;
+		while (!HardwareImpl::txComplete())
+			;
+		HardwareImpl::clearTxComplete();
+	}
+
+  private:
+	using HardwareImpl = Hardware<Registers, CtrlFlagsA, CtrlFlagsB, CtrlFlagsC, cfg, Driven::BLOCKING, mode>;
 };
 
+template <class Registers, typename CtrlFlagsA, typename CtrlFlagsB, typename CtrlFlagsC, class cfg, Mode mode>
+class InterruptHardware {
+  public:
+	using data_t = typename cfg::data_t;
+	static constexpr auto DATA_BITS = cfg::DATA_BITS;
+
+	[[gnu::always_inline]] static void txByte(const data_t &byte)
+	{
+		std::uint8_t tmpHead = (sm_txBuf.head + 1) % TX_BUFFER_SIZE;
+		while (tmpHead == sm_txBuf.tail)
+			;
+
+		sm_txBuf.buf[tmpHead] = byte;
+		sm_txBuf.head = tmpHead;
+
+		HardwareImpl::enableDataRegEmptyInt();
+	}
+
+	[[gnu::always_inline]] static bool rxByte(data_t &byte)
+	{
+		if (sm_rxBuf.head == sm_rxBuf.tail)
+			return false;
+
+		std::uint8_t tmpTail = (sm_rxBuf.tail + 1) % RX_BUFFER_SIZE;
+		byte = sm_rxBuf.buf[tmpTail];
+		sm_rxBuf.tail = tmpTail;
+
+		return true;
+	}
+
+	[[gnu::always_inline]] static bool peek(data_t &byte)
+	{
+		if (sm_rxBuf.head == sm_rxBuf.tail)
+			return false;
+
+		std::uint8_t tmpTail = (sm_rxBuf.tail + 1) % RX_BUFFER_SIZE;
+		byte = sm_rxBuf.buf[tmpTail];
+
+		return true;
+	}
+
+	[[gnu::always_inline]] static bool peek()
+	{
+		return (sm_rxBuf.head != sm_rxBuf.tail);
+	}
+
+	[[gnu::always_inline]] static void flushTx()
+	{
+		while (sm_txBuf.head != sm_txBuf.tail)
+			;
+		while (!HardwareImpl::txEmpty())
+			;
+		while (!HardwareImpl::txComplete())
+			;
+		HardwareImpl::clearTxComplete();
+	}
+
+  protected:
+	[[gnu::always_inline]] static void rxIntHandler()
+	{
+		const auto data = HardwareImpl::rxByteInterrupt();
+
+		const std::uint8_t tmpHead = (sm_rxBuf.head + 1) % RX_BUFFER_SIZE;
+
+		if (tmpHead != sm_rxBuf.tail) {
+			sm_rxBuf.head = tmpHead;
+			sm_rxBuf.buf[tmpHead] = data;
+		} else {
+			// TODO: Handle overflow
+		}
+	}
+
+	[[gnu::always_inline]] static void dataRegEmptyIntHandler()
+	{
+		if (sm_txBuf.head != sm_txBuf.tail) {
+			const std::uint8_t tmpTail = (sm_txBuf.tail + 1) % TX_BUFFER_SIZE;
+			sm_txBuf.tail = tmpTail;
+			HardwareImpl::txByteInterrupt(sm_txBuf.buf[tmpTail]);
+		} else
+			HardwareImpl::disableDataRegEmptyInt();
+	}
+
+  private:
+	using HardwareImpl = Hardware<Registers, CtrlFlagsA, CtrlFlagsB, CtrlFlagsC, cfg, Driven::INTERRUPT, mode>;
+
+	static constexpr auto TX_BUFFER_SIZE = 16;
+	static constexpr auto RX_BUFFER_SIZE = 16;
+
+	static volatile RingBuffer<data_t, TX_BUFFER_SIZE> sm_txBuf;
+	static volatile RingBuffer<data_t, RX_BUFFER_SIZE> sm_rxBuf;
+};
+
+template <class Registers, typename CtrlFlagsA, typename CtrlFlagsB, typename CtrlFlagsC, class cfg, Mode mode>
+volatile RingBuffer<typename InterruptHardware<Registers, CtrlFlagsA, CtrlFlagsB, CtrlFlagsC, cfg, mode>::data_t,
+                    InterruptHardware<Registers, CtrlFlagsA, CtrlFlagsB, CtrlFlagsC, cfg, mode>::TX_BUFFER_SIZE>
+    InterruptHardware<Registers, CtrlFlagsA, CtrlFlagsB, CtrlFlagsC, cfg, mode>::sm_txBuf = {0, 0, {0}};
+
+template <class Registers, typename CtrlFlagsA, typename CtrlFlagsB, typename CtrlFlagsC, class cfg, Mode mode>
+volatile RingBuffer<typename InterruptHardware<Registers, CtrlFlagsA, CtrlFlagsB, CtrlFlagsC, cfg, mode>::data_t,
+                    InterruptHardware<Registers, CtrlFlagsA, CtrlFlagsB, CtrlFlagsC, cfg, mode>::RX_BUFFER_SIZE>
+    InterruptHardware<Registers, CtrlFlagsA, CtrlFlagsB, CtrlFlagsC, cfg, mode>::sm_rxBuf = {0, 0, {0}};
+
 } // namespace detail
 
 } // namespace uart
-
-#undef FORCE_INLINE

hardware0.cpp

@@ -1,30 +0,0 @@
-#include "hardware0.hpp"
-
-#include <avr/interrupt.h>
-
-namespace uart {
-namespace detail {
-
-#if defined(__AVR_ATmega1284P__)
-
-void (*fnRx0IntHandler)() = nullptr;
-void (*fnDataReg0EmptyIntHandler)() = nullptr;
-
-ISR(USART0_RX_vect)
-{
-	if (fnRx0IntHandler)
-		fnRx0IntHandler();
-}
-
-ISR(USART0_UDRE_vect)
-{
-	if (fnDataReg0EmptyIntHandler)
-		fnDataReg0EmptyIntHandler();
-}
-
-#else
-#error "This chip is not supported"
-#endif
-
-} // namespace detail
-} // namespace uart

hardware0.hpp

@@ -1,30 +1,45 @@
 #pragma once
 
-#include <stdint.h>
+#include <cstdint>
 
 #include <avr/interrupt.h>
 #include <avr/io.h>
+#include <avr/sfr_defs.h>
 
 #include "config.hpp"
 #include "hardware.hpp"
 
-#define FORCE_INLINE __attribute__((always_inline))
-
 namespace uart {
 
 namespace detail {
 
-#if defined(__AVR_ATmega1284P__)
+#if defined(__AVR_ATmega1284P__) || defined(__AVR_ATmega328P__)
+
+/*
+The following works in avr-gcc 5.4.0, but is not legal C++, because ptr's are not legal constexpr's:
+  constexpr auto *foo = ptr;
+
+Workaround is to store the the address of the ptr in a uintptr_t and reinterpret_cast it at call site.
+The _SFR_ADDR macro in sfr_defs.h would give the address, but it does that by taking the address of the dereferenced
+pointer and casts it to uint16_t, which is still not a legal constexpr.
+The workaround therefore is to disable the pointer cast and dereference macro _MMIO_BYTE temporarily.
+*/
+
+#pragma push_macro("_MMIO_BYTE")
+#undef _MMIO_BYTE
+#define _MMIO_BYTE
 
 struct Registers0 {
-	static constexpr volatile auto *IO_REG = &UDR0;
+	static constexpr std::uintptr_t IO_REG_ADDR = UDR0;
-	static constexpr volatile auto *CTRL_STAT_REG_A = &UCSR0A;
+	static constexpr std::uintptr_t CTRL_STAT_REG_A_ADDR = UCSR0A;
-	static constexpr volatile auto *CTRL_STAT_REG_B = &UCSR0B;
+	static constexpr std::uintptr_t CTRL_STAT_REG_B_ADDR = UCSR0B;
-	static constexpr volatile auto *CTRL_STAT_REG_C = &UCSR0C;
+	static constexpr std::uintptr_t CTRL_STAT_REG_C_ADDR = UCSR0C;
-	static constexpr volatile auto *BAUD_REG_L = &UBRR0L;
+	static constexpr std::uintptr_t BAUD_REG_L_ADDR = UBRR0L;
-	static constexpr volatile auto *BAUD_REG_H = &UBRR0H;
+	static constexpr std::uintptr_t BAUD_REG_H_ADDR = UBRR0H;
 };
 
+#pragma pop_macro("_MMIO_BYTE")
+
 enum class ControlFlagsA0 {
 	MULTI_PROC_COMM_MODE = MPCM0,
 	SPEED_2X = U2X0,
@@ -64,8 +79,10 @@ constexpr int operator<<(const int &lhs, const ControlFlagsB0 &rhs) { return lhs
 constexpr int operator<<(const int &lhs, const ControlFlagsC0 &rhs) { return lhs << static_cast<int>(rhs); }
 // clang-format on
 
-extern void (*fnRx0IntHandler)();
+#if defined(__AVR_ATmega328P__)
-extern void (*fnDataReg0EmptyIntHandler)();
+#define USART0_RX_vect USART_RX_vect
+#define USART0_UDRE_vect USART_UDRE_vect
+#endif
 
 #else
 #error "This chip is not supported"
@@ -73,160 +90,63 @@ extern void (*fnDataReg0EmptyIntHandler)();
 
 } // namespace detail
 
-template <Mode mode = Mode::ASYNCHRONOUS, class cfg = Config<>, Driven driven = Driven::INTERRUPT>
+template <class cfg = Config<>, Driven driven = Driven::INTERRUPT, Mode mode = Mode::ASYNCHRONOUS>
-class Hardware0 {
+class Hardware0 : public detail::BlockingHardware<detail::Registers0, detail::ControlFlagsA0, detail::ControlFlagsB0,
-  public:
+                                                  detail::ControlFlagsC0, cfg, mode> {
-	using data_t = typename cfg::data_t;
-	static constexpr auto DATA_BITS = cfg::DATA_BITS;
-
-	static void init() FORCE_INLINE
-	{
-		HardwareImpl::init();
-	}
-
-	static void txByte(data_t byte) FORCE_INLINE
-	{
-		HardwareImpl::txByteBlocking(byte);
-	}
-
-	static bool rxByte(data_t &byte) FORCE_INLINE
-	{
-		return HardwareImpl::rxByteBlocking(byte);
-	}
-
-	static bool peek(data_t &byte) FORCE_INLINE
-	{
-		static_cast<void>(byte);
-		static_assert(driven == Driven::BLOCKING, "Peek with data is not supported in blocking mode");
-		return false;
-	}
-
-	static bool peek() FORCE_INLINE
-	{
-		return HardwareImpl::peekBlocking();
-	}
-
-	static void flushTx() FORCE_INLINE
-	{
-		while (!HardwareImpl::txEmpty())
-			;
-		while (!HardwareImpl::txComplete())
-			;
-		HardwareImpl::clearTxComplete();
-	}
-
-  private:
-	using HardwareImpl = detail::Hardware<detail::Registers0, detail::ControlFlagsA0, detail::ControlFlagsB0,
-	                                      detail::ControlFlagsC0, cfg, mode, driven>;
 };
 
-template <Mode mode, class cfg>
+template <class cfg, Mode mode>
-class Hardware0<mode, cfg, Driven::INTERRUPT> {
+class Hardware0<cfg, Driven::INTERRUPT, mode>
+    : public detail::InterruptHardware<detail::Registers0, detail::ControlFlagsA0, detail::ControlFlagsB0,
+                                       detail::ControlFlagsC0, cfg, mode> {
   public:
-	using data_t = typename cfg::data_t;
+	[[gnu::always_inline]] static void init()
-	static constexpr auto DATA_BITS = cfg::DATA_BITS;
-
-	static void init() FORCE_INLINE
 	{
-		detail::fnRx0IntHandler = rxIntHandler;
-		detail::fnDataReg0EmptyIntHandler = dataRegEmptyIntHandler;
-
 		HardwareImpl::init();
 		sei();
 	}
 
-	static void txByte(const data_t &byte) FORCE_INLINE
-	{
-		uint8_t tmpHead = (sm_txBuf.head + 1) % TX_BUFFER_SIZE;
-		while (tmpHead == sm_txBuf.tail)
-			;
-
-		sm_txBuf.buf[tmpHead] = byte;
-		sm_txBuf.head = tmpHead;
-
-		HardwareImpl::enableDataRegEmptyInt();
-	}
-
-	static bool rxByte(data_t &byte) FORCE_INLINE
-	{
-		if (sm_rxBuf.head == sm_rxBuf.tail)
-			return false;
-
-		uint8_t tmpTail = (sm_rxBuf.tail + 1) % RX_BUFFER_SIZE;
-		byte = sm_rxBuf.buf[tmpTail];
-		sm_rxBuf.tail = tmpTail;
-
-		return true;
-	}
-
-	static bool peek(data_t &byte) FORCE_INLINE
-	{
-		if (sm_rxBuf.head == sm_rxBuf.tail)
-			return false;
-
-		uint8_t tmpTail = (sm_rxBuf.tail + 1) % RX_BUFFER_SIZE;
-		byte = sm_rxBuf.buf[tmpTail];
-
-		return true;
-	}
-
-	static bool peek() FORCE_INLINE
-	{
-		return (sm_rxBuf.head != sm_rxBuf.tail);
-	}
-
-	static void flushTx() FORCE_INLINE
-	{
-		while (sm_txBuf.head != sm_txBuf.tail)
-			;
-		while (!HardwareImpl::txEmpty())
-			;
-		while (!HardwareImpl::txComplete())
-			;
-		HardwareImpl::clearTxComplete();
-	}
-
   private:
 	using HardwareImpl = detail::Hardware<detail::Registers0, detail::ControlFlagsA0, detail::ControlFlagsB0,
-	                                      detail::ControlFlagsC0, cfg, mode, Driven::INTERRUPT>;
+	                                      detail::ControlFlagsC0, cfg, Driven::INTERRUPT, mode>;
 
-	static constexpr auto TX_BUFFER_SIZE = 16;
+	using InterruptHardwareImpl = detail::InterruptHardware<detail::Registers0, detail::ControlFlagsA0,
-	static constexpr auto RX_BUFFER_SIZE = 16;
+	                                                        detail::ControlFlagsB0, detail::ControlFlagsC0, cfg, mode>;
 
-	static volatile detail::RingBuffer<data_t, TX_BUFFER_SIZE> sm_txBuf;
+	// Must be friends with Uart interface to call these private handlers
-	static volatile detail::RingBuffer<data_t, RX_BUFFER_SIZE> sm_rxBuf;
+	template <class Driver>
+	friend class Uart;
 
-	static void rxIntHandler()
+	[[gnu::always_inline]] static void rxIntHandler()
 	{
-		uint8_t tmpHead = (sm_rxBuf.head + 1) % RX_BUFFER_SIZE;
+		InterruptHardwareImpl::rxIntHandler();
-
-		if (tmpHead != sm_rxBuf.tail) {
-			sm_rxBuf.head = tmpHead;
-			sm_rxBuf.buf[tmpHead] = HardwareImpl::rxByteInterrupt();
-		}
 	}
 
-	static void dataRegEmptyIntHandler() FORCE_INLINE
+	[[gnu::always_inline]] static void dataRegEmptyIntHandler()
 	{
-		if (sm_txBuf.head != sm_txBuf.tail) {
+		InterruptHardwareImpl::dataRegEmptyIntHandler();
-			uint8_t tmpTail = (sm_txBuf.tail + 1) % TX_BUFFER_SIZE;
-			sm_txBuf.tail = tmpTail;
-			HardwareImpl::txByteInterrupt(sm_txBuf.buf[tmpTail]);
-		} else
-			HardwareImpl::disableDataRegEmptyInt();
 	}
 };
 
-template <Mode mode, class cfg>
-volatile detail::RingBuffer<typename Hardware0<mode, cfg, Driven::INTERRUPT>::data_t,
-                            Hardware0<mode, cfg, Driven::INTERRUPT>::TX_BUFFER_SIZE>
-    Hardware0<mode, cfg, Driven::INTERRUPT>::sm_txBuf = {0, 0, {0}};
-
-template <Mode mode, class cfg>
-volatile detail::RingBuffer<typename Hardware0<mode, cfg, Driven::INTERRUPT>::data_t,
-                            Hardware0<mode, cfg, Driven::INTERRUPT>::RX_BUFFER_SIZE>
-    Hardware0<mode, cfg, Driven::INTERRUPT>::sm_rxBuf = {0, 0, {0}};
-
 } // namespace uart
 
-#undef FORCE_INLINE
+//////////////////////////////////////////////////////////////////////////
+
+// Forward declare interrupt functions to allow adding them as friends
+extern "C" {
+void USART0_RX_vect() __attribute__((signal));
+void USART0_UDRE_vect() __attribute__((signal));
+}
+
+// clang-format off
+#define REGISTER_UART0_INT_VECTORS(uart_type) \
+	ISR(USART0_RX_vect)                       \
+	{                                         \
+		uart_type::rxIntHandler();            \
+	}                                         \
+	ISR(USART0_UDRE_vect)                     \
+	{                                         \
+		uart_type::dataRegEmptyIntHandler();  \
+	}                                         \
+	struct _##uart_type {}
+// clang-format on

hardware1.cpp

@@ -1,30 +0,0 @@
-#include "hardware1.hpp"
-
-#include <avr/interrupt.h>
-
-namespace uart {
-namespace detail {
-
-#if defined(__AVR_ATmega1284P__)
-
-void (*fnRx1IntHandler)() = nullptr;
-void (*fnDataReg1EmptyIntHandler)() = nullptr;
-
-ISR(USART1_RX_vect)
-{
-	if (fnRx1IntHandler)
-		fnRx1IntHandler();
-}
-
-ISR(USART1_UDRE_vect)
-{
-	if (fnDataReg1EmptyIntHandler)
-		fnDataReg1EmptyIntHandler();
-}
-
-#else
-#error "This chip is not supported"
-#endif
-
-} // namespace detail
-} // namespace uart

hardware1.hpp

@@ -1,30 +1,45 @@
 #pragma once
 
-#include <stdint.h>
+#include <cstdint>
 
 #include <avr/interrupt.h>
 #include <avr/io.h>
+#include <avr/sfr_defs.h>
 
 #include "config.hpp"
 #include "hardware.hpp"
 
-#define FORCE_INLINE __attribute__((always_inline))
-
 namespace uart {
 
 namespace detail {
 
 #if defined(__AVR_ATmega1284P__)
 
+/*
+The following works in avr-gcc 5.4.0, but is not legal C++, because ptr's are not legal constexpr's:
+  constexpr auto *foo = ptr;
+
+Workaround is to store the the address of the ptr in a uintptr_t and reinterpret_cast it at call site.
+The _SFR_ADDR macro in sfr_defs.h would give the address, but it does that by taking the address of the dereferenced
+pointer and casts it to uint16_t, which is still not a legal constexpr.
+The workaround therefore is to disable the pointer cast and dereference macro _MMIO_BYTE temporarily.
+*/
+
+#pragma push_macro("_MMIO_BYTE")
+#undef _MMIO_BYTE
+#define _MMIO_BYTE
+
 struct Registers1 {
-	static constexpr volatile auto *IO_REG = &UDR1;
+	static constexpr std::uintptr_t IO_REG_ADDR = UDR1;
-	static constexpr volatile auto *CTRL_STAT_REG_A = &UCSR1A;
+	static constexpr std::uintptr_t CTRL_STAT_REG_A_ADDR = UCSR1A;
-	static constexpr volatile auto *CTRL_STAT_REG_B = &UCSR1B;
+	static constexpr std::uintptr_t CTRL_STAT_REG_B_ADDR = UCSR1B;
-	static constexpr volatile auto *CTRL_STAT_REG_C = &UCSR1C;
+	static constexpr std::uintptr_t CTRL_STAT_REG_C_ADDR = UCSR1C;
-	static constexpr volatile auto *BAUD_REG_L = &UBRR1L;
+	static constexpr std::uintptr_t BAUD_REG_L_ADDR = UBRR1L;
-	static constexpr volatile auto *BAUD_REG_H = &UBRR1H;
+	static constexpr std::uintptr_t BAUD_REG_H_ADDR = UBRR1H;
 };
 
+#pragma pop_macro("_MMIO_BYTE")
+
 enum class ControlFlagsA1 {
 	MULTI_PROC_COMM_MODE = MPCM1,
 	SPEED_2X = U2X1,
@@ -64,175 +79,79 @@ constexpr int operator<<(const int &lhs, const ControlFlagsB1 &rhs) { return lhs
 constexpr int operator<<(const int &lhs, const ControlFlagsC1 &rhs) { return lhs << static_cast<int>(rhs); }
 // clang-format on
 
-extern void (*fnRx1IntHandler)();
-extern void (*fnDataReg1EmptyIntHandler)();
-
 #define HAS_UART1
 
-#else
-#error "This chip is not supported"
 #endif
 
 } // namespace detail
 
 #ifdef HAS_UART1
 
-template <Mode mode = Mode::ASYNCHRONOUS, class cfg = Config<>, Driven driven = Driven::INTERRUPT>
+template <class cfg = Config<>, Driven driven = Driven::INTERRUPT, Mode mode = Mode::ASYNCHRONOUS>
-class Hardware1 {
+class Hardware1 : public detail::BlockingHardware<detail::Registers1, detail::ControlFlagsA1, detail::ControlFlagsB1,
-  public:
+                                                  detail::ControlFlagsC1, cfg, mode> {
-	using data_t = typename cfg::data_t;
-	static constexpr auto DATA_BITS = cfg::DATA_BITS;
-
-	static void init() FORCE_INLINE
-	{
-		HardwareImpl::init();
-	}
-
-	static void txByte(const data_t &byte) FORCE_INLINE
-	{
-		HardwareImpl::txByteBlocking(byte);
-	}
-
-	static bool rxByte(data_t &byte) FORCE_INLINE
-	{
-		return HardwareImpl::rxByteBlocking(byte);
-	}
-
-	static bool peek(data_t &byte) FORCE_INLINE
-	{
-		static_cast<void>(byte);
-		static_assert(driven != Driven::BLOCKING, "Peek with data is not supported in blocking mode");
-		return false;
-	}
-
-	static bool peek() FORCE_INLINE
-	{
-		return HardwareImpl::peekBlocking();
-	}
-
-	static void flushTx() FORCE_INLINE
-	{
-		while (!HardwareImpl::txEmpty())
-			;
-		while (!HardwareImpl::txComplete())
-			;
-		HardwareImpl::clearTxComplete();
-	}
-
-  private:
-	using HardwareImpl = detail::Hardware<detail::Registers1, detail::ControlFlagsA1, detail::ControlFlagsB1,
-	                                      detail::ControlFlagsC1, cfg, mode, driven>;
 };
 
-template <Mode mode, class cfg>
+template <class cfg, Mode mode>
-class Hardware1<mode, cfg, Driven::INTERRUPT> {
+class Hardware1<cfg, Driven::INTERRUPT, mode>
+    : public detail::InterruptHardware<detail::Registers1, detail::ControlFlagsA1, detail::ControlFlagsB1,
+                                       detail::ControlFlagsC1, cfg, mode> {
   public:
-	using data_t = typename cfg::data_t;
+	[[gnu::always_inline]] static void init()
-	static constexpr auto DATA_BITS = cfg::DATA_BITS;
-
-	static void init() FORCE_INLINE
 	{
-		detail::fnRx1IntHandler = rxIntHandler;
-		detail::fnDataReg1EmptyIntHandler = dataRegEmptyIntHandler;
-
 		HardwareImpl::init();
 		sei();
 	}
 
-	static void txByte(const data_t &byte) FORCE_INLINE
-	{
-		uint8_t tmpHead = (sm_txBuf.head + 1) % TX_BUFFER_SIZE;
-		while (tmpHead == sm_txBuf.tail)
-			;
-
-		sm_txBuf.buf[tmpHead] = byte;
-		sm_txBuf.head = tmpHead;
-
-		HardwareImpl::enableDataRegEmptyInt();
-	}
-
-	static bool rxByte(data_t &byte) FORCE_INLINE
-	{
-		if (sm_rxBuf.head == sm_rxBuf.tail)
-			return false;
-
-		uint8_t tmpTail = (sm_rxBuf.tail + 1) % RX_BUFFER_SIZE;
-		byte = sm_rxBuf.buf[tmpTail];
-		sm_rxBuf.tail = tmpTail;
-
-		return true;
-	}
-
-	static bool peek(data_t &byte) FORCE_INLINE
-	{
-		if (sm_rxBuf.head == sm_rxBuf.tail)
-			return false;
-
-		uint8_t tmpTail = (sm_rxBuf.tail + 1) % RX_BUFFER_SIZE;
-		byte = sm_rxBuf.buf[tmpTail];
-
-		return true;
-	}
-
-	static bool peek() FORCE_INLINE
-	{
-		return (sm_rxBuf.head != sm_rxBuf.tail);
-	}
-
-	static void flushTx() FORCE_INLINE
-	{
-		while (sm_txBuf.head != sm_txBuf.tail)
-			;
-		while (!HardwareImpl::txEmpty())
-			;
-		while (!HardwareImpl::txComplete())
-			;
-		HardwareImpl::clearTxComplete();
-	}
-
   private:
 	using HardwareImpl = detail::Hardware<detail::Registers1, detail::ControlFlagsA1, detail::ControlFlagsB1,
-	                                      detail::ControlFlagsC1, cfg, mode, Driven::INTERRUPT>;
+	                                      detail::ControlFlagsC1, cfg, Driven::INTERRUPT, mode>;
 
-	static constexpr auto TX_BUFFER_SIZE = 16;
+	using InterruptHardwareImpl = detail::InterruptHardware<detail::Registers1, detail::ControlFlagsA1,
-	static constexpr auto RX_BUFFER_SIZE = 16;
+	                                                        detail::ControlFlagsB1, detail::ControlFlagsC1, cfg, mode>;
 
-	static volatile detail::RingBuffer<data_t, TX_BUFFER_SIZE> sm_txBuf;
+	// Must be friends with Uart interface to call these private handlers
-	static volatile detail::RingBuffer<data_t, RX_BUFFER_SIZE> sm_rxBuf;
+	template <class Driver>
+	friend class Uart;
 
-	static void rxIntHandler()
+	[[gnu::always_inline]] static void rxIntHandler()
 	{
-		uint8_t tmpHead = (sm_rxBuf.head + 1) % RX_BUFFER_SIZE;
+		InterruptHardwareImpl::rxIntHandler();
-
-		if (tmpHead != sm_rxBuf.tail) {
-			sm_rxBuf.head = tmpHead;
-			sm_rxBuf.buf[tmpHead] = HardwareImpl::rxByteInterrupt();
-		}
 	}
 
-	static void dataRegEmptyIntHandler() FORCE_INLINE
+	[[gnu::always_inline]] static void dataRegEmptyIntHandler()
 	{
-		if (sm_txBuf.head != sm_txBuf.tail) {
+		InterruptHardwareImpl::dataRegEmptyIntHandler();
-			uint8_t tmpTail = (sm_txBuf.tail + 1) % TX_BUFFER_SIZE;
-			sm_txBuf.tail = tmpTail;
-			HardwareImpl::txByteInterrupt(sm_txBuf.buf[tmpTail]);
-		} else
-			HardwareImpl::disableDataRegEmptyInt();
 	}
 };
 
-template <Mode mode, class cfg>
-volatile detail::RingBuffer<typename Hardware1<mode, cfg, Driven::INTERRUPT>::data_t,
-                            Hardware1<mode, cfg, Driven::INTERRUPT>::TX_BUFFER_SIZE>
-    Hardware1<mode, cfg, Driven::INTERRUPT>::sm_txBuf = {0, 0, {0}};
-
-template <Mode mode, class cfg>
-volatile detail::RingBuffer<typename Hardware1<mode, cfg, Driven::INTERRUPT>::data_t,
-                            Hardware1<mode, cfg, Driven::INTERRUPT>::RX_BUFFER_SIZE>
-    Hardware1<mode, cfg, Driven::INTERRUPT>::sm_rxBuf = {0, 0, {0}};
-
 #endif
 
 } // namespace uart
 
-#undef FORCE_INLINE
+//////////////////////////////////////////////////////////////////////////
+
+#ifdef HAS_UART1
+
+// Forward declare interrupt functions to allow adding them as friends
+extern "C" {
+void USART1_RX_vect() __attribute__((signal));
+void USART1_UDRE_vect() __attribute__((signal));
+}
+
+// clang-format off
+#define REGISTER_UART1_INT_VECTORS(uart_type) \
+	ISR(USART1_RX_vect)                       \
+	{                                         \
+		uart_type::rxIntHandler();            \
+	}                                         \
+	ISR(USART1_UDRE_vect)                     \
+	{                                         \
+		uart_type::dataRegEmptyIntHandler();  \
+	}                                         \
+	struct _##uart_type {                     \
+	}
+// clang-format off
+
+#endif
+

software.hpp

@@ -1,9 +1,9 @@
 #pragma once
 
 #include "config.hpp"
-#include "utils.hpp"
 
 #include "../io/io.hpp"
+#include "../util/util.hpp"
 
 namespace uart {
 

uart.hpp

@@ -1,26 +1,27 @@
 #pragma once
 
-#include <stdint.h>
+#include <limits>
+
+#include <cstdint>
 
 #include "config.hpp"
+#include "software.hpp"
+
 #include "hardware0.hpp"
 #include "hardware1.hpp"
-#include "software.hpp"
-#include "utils.hpp"
 
 #include "../flash/flash.hpp"
-
+#include "../util/util.hpp"
-#define FORCE_INLINE __attribute__((always_inline))
 
 namespace uart {
 
 namespace detail {
 
-template <typename T, T limit, size_t Base>
+template <typename T, T Limit, std::size_t Base>
-static constexpr size_t cntDigits()
+static constexpr std::size_t cntDigits()
 {
-	T num = limit;
+	T num = Limit;
-	size_t cnt = 0;
+	std::size_t cnt = 0;
 
 	do {
 		num /= Base;
@@ -30,28 +31,16 @@ static constexpr size_t cntDigits()
 	return cnt;
 }
 
-template <typename T, size_t Base>
+template <typename T, std::size_t Base>
-static constexpr size_t maxNumDigits()
+static constexpr std::size_t maxNumDigits()
 {
-	constexpr T minVal = util::NumericLimits<T>::min();
+	constexpr T MinVal = std::numeric_limits<T>::min();
-	constexpr T maxVal = util::NumericLimits<T>::max();
+	constexpr T MaxVal = std::numeric_limits<T>::max();
 
-	T minDigits = cntDigits<T, minVal, Base>() + ((minVal < 0) ? 1 : 0);
+	constexpr T MinDigits = cntDigits<T, MinVal, Base>();
-	T maxDigits = cntDigits<T, maxVal, Base>() + ((maxVal < 0) ? 1 : 0);
+	constexpr T MaxDigits = cntDigits<T, MaxVal, Base>();
 
-	return (minDigits < maxDigits) ? maxDigits : minDigits;
+	return (MinDigits < MaxDigits) ? MaxDigits : MinDigits;
-}
-
-template <typename T, size_t Base>
-static constexpr size_t maxPadding()
-{
-	constexpr T minVal = util::NumericLimits<T>::min();
-	constexpr T maxVal = util::NumericLimits<T>::max();
-
-	T minDigits = cntDigits<T, minVal, Base>();
-	T maxDigits = cntDigits<T, maxVal, Base>();
-
-	return (minDigits < maxDigits) ? maxDigits : minDigits;
 }
 
 } // namespace detail
@@ -121,19 +110,16 @@ class Uart {
 			txByte(ch);
 	}
 
-	template <typename T, size_t Base = 10, size_t Padding = 0, char PadChar = '0', bool LowerCase = true>
+	template <typename T, std::size_t Base = 10, std::size_t Padding = 0, char PadChar = '0', bool LowerCase = true>
 	static void txNumber(const T &val)
 	{
-		static_assert(util::is_integral_v<T>, "Only supported on integral types");
+		static_assert(std::is_integral_v<T>, "Only supported on integral types");
-		static_assert(Base >= 2, "Numbers with bases less than 2 make no sense");
+		static_assert(Base >= 2, "Numbers with base less than 2 make no sense");
-		static_assert(Base <= 16, "Numbers with bases higher than 16 are not supported");
+		static_assert(Base <= 16, "Numbers with base higher than 16 are not supported");
-		static_assert(Padding <= detail::maxPadding<T, Base>(), "Cannot pad more than maximum length of number");
+		static_assert(Padding <= detail::maxNumDigits<T, Base>(), "Cannot pad more than maximum length of number");
 
-		constexpr char alphaChar = (LowerCase) ? 'a' : 'A';
+		constexpr char AlphaChar = (LowerCase) ? 'a' : 'A';
-		constexpr size_t numDigits = detail::maxNumDigits<T, Base>();
+		constexpr std::size_t NumDigits = detail::maxNumDigits<T, Base>();
-
-		data_t buffer[numDigits];
-		data_t *bufEnd = buffer + numDigits - 1;
 
 		T digits = val;
 
@@ -142,23 +128,26 @@ class Uart {
 			txByte('-');
 		}
 
+		data_t buffer[NumDigits];
+		data_t *bufEnd = buffer + NumDigits - 1;
+
 		do {
-			data_t lastDigit = digits % Base;
+			const data_t lastDigit = digits % Base;
-			*bufEnd-- = (lastDigit < 10) ? ('0' + lastDigit) : (alphaChar + lastDigit - 10);
+			*bufEnd-- = (lastDigit < 10) ? ('0' + lastDigit) : (AlphaChar + lastDigit - 10);
 			digits /= Base;
 		} while (digits > 0);
 
 		if (Padding > 0) {
-			size_t strLen = buffer + numDigits - (bufEnd + 1);
+			std::size_t strLen = buffer + NumDigits - (bufEnd + 1);
 
 			if (Padding > strLen) {
-				for (size_t i = Padding; i > strLen && bufEnd >= buffer; --i) {
+				for (std::size_t i = Padding; i > strLen && bufEnd >= buffer; --i) {
 					*bufEnd-- = PadChar;
 				}
 			}
 		}
 
-		for (data_t *buf = bufEnd + 1; buf < buffer + numDigits; ++buf)
+		for (data_t *buf = bufEnd + 1; buf < buffer + NumDigits; ++buf)
 			txByte(*buf);
 	}
 
@@ -201,7 +190,7 @@ class Uart {
 		return *this;
 	}
 
-	Uart &operator<<(unsigned short &val)
+	Uart &operator<<(const unsigned short &val)
 	{
 		txNumber(val);
 		return *this;
@@ -225,19 +214,19 @@ class Uart {
 		return *this;
 	}
 
-	Uart &operator<<(unsigned long &val)
+	Uart &operator<<(const unsigned long &val)
 	{
 		txNumber(val);
 		return *this;
 	}
 
-	Uart &operator<<(long long &val)
+	Uart &operator<<(const long long &val)
 	{
 		txNumber(val);
 		return *this;
 	}
 
-	Uart &operator<<(unsigned long long &val)
+	Uart &operator<<(const unsigned long long &val)
 	{
 		txNumber(val);
 		return *this;
@@ -246,19 +235,19 @@ class Uart {
 	template <typename... Ts>
 	Uart &operator<<(float) const
 	{
-		static_assert(util::always_false_v<Ts...>, "Not implemented");
+		static_assert(util::always_false_v<Ts...>, "Not supported by hardware");
 	}
 
 	template <typename... Ts>
 	Uart &operator<<(double) const
 	{
-		static_assert(util::always_false_v<Ts...>, "Not implemented");
+		static_assert(util::always_false_v<Ts...>, "Not supported by hardware");
 	}
 
 	template <typename... Ts>
 	Uart &operator<<(long double) const
 	{
-		static_assert(util::always_false_v<Ts...>, "Not implemented");
+		static_assert(util::always_false_v<Ts...>, "Not supported by hardware");
 	}
 
 	Uart &operator<<(const bool &val)
@@ -270,7 +259,7 @@ class Uart {
 	Uart &operator<<(const void *val)
 	{
 		txString(F("0x"));
-		txNumber<uint16_t, 16>(reinterpret_cast<uint16_t>(val));
+		txNumber<std::uint16_t, 16, 4, '0', false>(reinterpret_cast<std::uint16_t>(val));
 		return *this;
 	}
 
@@ -340,19 +329,19 @@ class Uart {
 	template <typename... Ts>
 	Uart &operator>>(float &) const
 	{
-		static_assert(util::always_false_v<Ts...>, "Not implemented");
+		static_assert(util::always_false_v<Ts...>, "Not supported by hardware");
 	}
 
 	template <typename... Ts>
 	Uart &operator>>(double &) const
 	{
-		static_assert(util::always_false_v<Ts...>, "Not implemented");
+		static_assert(util::always_false_v<Ts...>, "Not supported by hardware");
 	}
 
 	template <typename... Ts>
 	Uart &operator>>(long double &) const
 	{
-		static_assert(util::always_false_v<Ts...>, "Not implemented");
+		static_assert(util::always_false_v<Ts...>, "Not supported by hardware");
 	}
 
 	template <typename... Ts>
@@ -366,17 +355,35 @@ class Uart {
 	{
 		static_assert(util::always_false_v<Ts...>, "Not implemented");
 	}
+
+  private:
+	friend void ::USART0_RX_vect();
+	friend void ::USART0_UDRE_vect();
+
+#ifdef HAS_UART1
+	friend void ::USART1_RX_vect();
+	friend void ::USART1_UDRE_vect();
+#endif
+
+	[[gnu::always_inline]] static void rxIntHandler()
+	{
+		Driver::rxIntHandler();
+	}
+
+	[[gnu::always_inline]] static void dataRegEmptyIntHandler()
+	{
+		Driver::dataRegEmptyIntHandler();
+	}
 };
 
 template <typename cfg = Config<>>
-using Uart0 = Uart<Hardware0<Mode::ASYNCHRONOUS, cfg>>;
+using Uart0 = Uart<Hardware0<cfg, Driven::INTERRUPT, Mode::ASYNCHRONOUS>>;
 
 #ifdef HAS_UART1
 template <typename cfg = Config<>>
-using Uart1 = Uart<Hardware1<Mode::ASYNCHRONOUS, cfg>>;
+using Uart1 = Uart<Hardware1<cfg, Driven::INTERRUPT, Mode::ASYNCHRONOUS>>;
 #endif
 
 } // namespace uart
 
-#undef FORCE_INLINE
 #undef HAS_UART1

utils.hpp

@@ -1,143 +0,0 @@
-#pragma once
-
-// Fix for limits.h not exposing LLONG_MIN, LLONG_MIN, and ULLONG_MAX to C++ context
-#ifdef __cplusplus
-#define __STDC_VERSION__ 201112L
-#endif
-
-#include <float.h>
-#include <limits.h>
-
-namespace uart {
-namespace util {
-
-// clang-format off
-template <bool Val> struct set_bool { static constexpr auto value = Val; };
-
-struct true_type : set_bool<true> {};
-struct false_type : set_bool<false> {};
-
-template <typename...> struct always_false : false_type {};
-
-template <typename... Ts> static constexpr auto always_false_v = always_false<Ts...>::value;
-
-template <typename T> struct is_integral : false_type {};
-template <> struct is_integral<bool> : true_type {};
-template <> struct is_integral<char> : true_type {};
-template <> struct is_integral<signed char> : true_type {};
-template <> struct is_integral<unsigned char> : true_type {};
-template <> struct is_integral<short> : true_type {};
-template <> struct is_integral<int> : true_type {};
-template <> struct is_integral<long int> : true_type {};
-template <> struct is_integral<long long int> : true_type {};
-template <> struct is_integral<unsigned short> : true_type {};
-template <> struct is_integral<unsigned int> : true_type {};
-template <> struct is_integral<unsigned long int> : true_type {};
-template <> struct is_integral<unsigned long long int> : true_type {};
-
-template <typename T> static constexpr auto is_integral_v = is_integral<T>::value;
-
-template <typename T, typename U> struct is_same : false_type {};
-template <typename T> struct is_same<T, T> : true_type {};
-
-template <typename T, typename U> static constexpr auto is_same_v = is_same<T, U>::value;
-
-template <typename T>
-struct NumericLimits {
-	static constexpr T min() { return T(); }
-	static constexpr T max() { return T(); }
-};
-
-template <>
-struct NumericLimits<bool> {
-	static constexpr bool min() { return false; }
-	static constexpr bool max() { return true; }
-};
-
-template <>
-struct NumericLimits<char> {
-	static constexpr char min() { return CHAR_MIN; }
-	static constexpr char max() { return CHAR_MAX; }
-};
-
-template <>
-struct NumericLimits<signed char> {
-	static constexpr signed char min() { return SCHAR_MIN; }
-	static constexpr signed char max() { return SCHAR_MAX; }
-};
-
-template <>
-struct NumericLimits<unsigned char> {
-	static constexpr unsigned char min() { return 0; }
-	static constexpr unsigned char max() { return UCHAR_MAX; }
-};
-
-template <>
-struct NumericLimits<short> {
-	static constexpr short min() { return SHRT_MIN; }
-	static constexpr short max() { return SHRT_MAX; }
-};
-
-template <>
-struct NumericLimits<int> {
-	static constexpr int min() { return INT_MIN; }
-	static constexpr int max() { return INT_MAX; }
-};
-
-template <>
-struct NumericLimits<long> {
-	static constexpr long int min() { return LONG_MIN; }
-	static constexpr long int max() { return LONG_MAX; }
-};
-
-template <>
-struct NumericLimits<long long int> {
-	static constexpr long long int min() { return LLONG_MIN; }
-	static constexpr long long int max() { return LLONG_MAX; }
-};
-
-template <>
-struct NumericLimits<unsigned short> {
-	static constexpr unsigned short min() { return 0; }
-	static constexpr unsigned short max() { return USHRT_MAX; }
-};
-
-template <>
-struct NumericLimits<unsigned int> {
-	static constexpr unsigned int min() { return 0; }
-	static constexpr unsigned int max() { return UINT_MAX; }
-};
-
-template <>
-struct NumericLimits<unsigned long int> {
-	static constexpr unsigned long int min() { return 0; }
-	static constexpr unsigned long int max() { return ULONG_MAX; }
-};
-
-template <>
-struct NumericLimits<unsigned long long int> {
-	static constexpr unsigned long long int min() { return 0; }
-	static constexpr unsigned long long int max() { return ULLONG_MAX; }
-};
-
-template <>
-struct NumericLimits<float> {
-	template <typename... Ts> static constexpr float min() { return FLT_MIN; }
-	template <typename... Ts> static constexpr float max() { return FLT_MAX; }
-};
-
-template <>
-struct NumericLimits<double> {
-	template <typename... Ts> static constexpr double min() { return DBL_MIN; }
-	template <typename... Ts> static constexpr double max() { return DBL_MAX; }
-};
-
-template <>
-struct NumericLimits<long double> {
-	template <typename... Ts> static constexpr long double min() { return LDBL_MIN; }
-	template <typename... Ts> static constexpr long double max() { return LDBL_MAX; }
-};
-// clang-format on
-
-} // namespace util
-} // namespace uart