funreg.hpp

@@ -14,29 +14,17 @@
  */
 #define FUNREG_ENABLE_EXTERNAL_IO
 
-/**
- * Comment to disable compile-time error checks, which are mostly concepts
- * to verify proper library usage.
- */
-#define FUNREG_ENABLE_ERROR_CHECKS
-
 #include <stdint.h>
 
 #ifdef FUNREG_ENABLE_EXTERNAL_IO
 #include <type_traits>
 #endif
 
-#ifdef FUNREG_ENABLE_ERROR_CHECKS
-#include <concepts>
-#endif
-
 namespace fr {
 
 // A utility to measure a bit-mask's offset from bit zero.
 template<auto Mask, unsigned int N = 0>
-requires(std::unsigned_integral<decltype(Mask)> &&
-         (N < 8 * sizeof(Mask)))
-constexpr auto BitOffset = []() constexpr -> unsigned int {
+constexpr auto BitOffset = []() constexpr {
     if constexpr (Mask & 1)
         return N;
     else
@@ -53,7 +41,6 @@ constexpr auto BitOffset = []() constexpr -> unsigned int {
  * structure as a template.
  */
 template<typename T, uintptr_t Addr>
-requires(std::unsigned_integral<T>)
 struct MemoryIO {
     using type = T;
     constexpr static auto addr = Addr;
@@ -73,54 +60,6 @@ struct MemoryIO {
     }
 };
 
-template<typename T>
-concept IsAccess = requires(typename T::type x) {
-    requires std::same_as<decltype(T::addr), const uintptr_t>;
-    {T::read()} -> std::same_as<typename T::type>;
-    {T::write(x)} -> std::same_as<void>;
-};
-
-#ifdef FUNREG_ENABLE_EXTERNAL_IO
-template<typename Access>
-requires IsAccess<Access>
-struct Register;
-
-template<typename T>
-concept IsRegister =
-    IsAccess<typename T::access> &&
-    std::same_as<T, Register<typename T::access>>;
-#else
-template<typename T, uintptr_t Addr>
-requires(std::unsigned_integral<T>)
-class Register;
-
-template<typename T>
-concept IsRegister =
-    std::unsigned_integral<typename T::type> &&
-    IsAccess<typename T::Access>;
-#endif
-
-template<typename Reg, typename Reg::type Mask>
-requires IsRegister<Reg>
-struct RegisterMask;
-
-template<typename T>
-concept IsRegisterMask =
-    IsRegister<typename T::reg> &&
-    std::same_as<T, RegisterMask<typename T::reg, T::mask>>;
-
-template<typename M, typename R>
-concept UsesRegister =
-    IsRegisterMask<M> &&
-    IsRegister<R> &&
-    std::same_as<typename M::reg, R>;
-
-template<typename M, typename... Rs>
-concept UsesSomeRegister =
-    IsRegisterMask<M> &&
-    (IsRegister<Rs>, ...) &&
-    (std::same_as<typename M::reg, Rs> || ...);
-
 /**
  * @struct Register
  * @brief  Defines a register, given how to access it.
@@ -131,22 +70,16 @@ concept UsesSomeRegister =
  */
 #ifdef FUNREG_ENABLE_EXTERNAL_IO
 template<typename Access>
-requires IsAccess<Access>
-class Register {
-public:
+struct Register {
     using access = Access;
     using T = typename Access::type;
     constexpr static auto Addr = Access::addr;
 #else
 template<typename T, uintptr_t Addr>
-requires(std::unsigned_integral<T>)
-class Register {
-public:
-    using Access = MemoryIO<T, Addr>;
+struct Register {
+    using RegAccess = MemoryIO<T, Addr>;
 #endif // FUNREG_ENABLE_EXTERNAL_IO
 
-    using type = T;
-
     /**
      * Gets a pointer to the register.
      */
@@ -165,8 +98,6 @@ public:
      * Sets register bits to '1' according to the given RegisterMasks.
      */
     template<typename... Masks>
-    requires((IsRegisterMask<Masks>, ...) &&
-             (UsesRegister<Masks, Register<Access>>, ...))
     static void set() {
         apply<Masks...>([](auto r, auto m) { return r | m; });
     }
@@ -182,8 +113,6 @@ public:
      * Clears register bits to '0' according to the given RegisterMasks.
      */
     template<typename... Masks>
-    requires((IsRegisterMask<Masks>, ...) &&
-             (UsesRegister<Masks, Register<Access>>, ...))
     static void clear() {
         apply<Masks...>([](auto r, auto m) { return r & ~m; });
     }
@@ -199,8 +128,6 @@ public:
      * Toggles bits in the register according to the given RegisterMasks.
      */
     template<typename... Masks>
-    requires((IsRegisterMask<Masks>, ...) &&
-             (UsesRegister<Masks, Register<Access>>, ...))
     static void toggle() {
         apply<Masks...>([](auto r, auto m) { return r ^m; });
     }
@@ -218,8 +145,6 @@ public:
      * If no masks are given, all register bits are returned.
      */
     template<typename... Masks>
-    requires((IsRegisterMask<Masks>, ...) &&
-             (UsesRegister<Masks, Register<Access>>, ...))
     static auto read() {
         if constexpr (sizeof...(Masks) > 0)
             return read() & mergeMasks<Masks...>();
@@ -232,8 +157,6 @@ public:
      * If no masks are given, tests if the register has a non-zero value.
      */
     template<typename... Masks>
-    requires((IsRegisterMask<Masks>, ...) &&
-             (UsesRegister<Masks, Register<Access>>, ...))
     static bool test() {
         if constexpr (sizeof...(Masks) > 0) {
             auto mask = mergeMasks<Masks...>();
@@ -262,16 +185,16 @@ public:
         }
     }
 
-    // Internal use only.
+    // Below is meant for internal use only.
+
     // Applies bit-masks to the register through the provided function.
-    // All masks meant for this register are merged together; then, `fn`
-    // will receive the register's current value and the mask to carry out
-    // the operation. The result is written back to the register.
+    // The provided function receives a pointer to the register's data and a
+    // bit-mask created by merging all provided bit-masks.
     // If no masks are given, a mask selecting all bits is used.
     template<typename... Masks>
-    constexpr static void apply(auto fn) {
+    static void apply(auto fn) {
         if constexpr (sizeof...(Masks) > 0) {
-            constexpr auto mask = mergeMasks<Masks...>();
+            auto mask = mergeMasks<Masks...>();
             if constexpr (mask)
                 write(fn(read(), mask));
         } else {
@@ -279,11 +202,10 @@ public:
         }
     }
 
-private:
     // Takes a list of bit-masks, and returns a merged mask of those which are
     // meant for this register.
     template<typename... Masks>
-    constexpr static auto mergeMasks() {
+    static auto mergeMasks() {
         if constexpr (sizeof...(Masks) > 0) {
             if constexpr ((isThis<typename Masks::reg> | ...)) {
                 auto mask =
@@ -302,20 +224,20 @@ private:
 #ifdef FUNREG_ENABLE_EXTERNAL_IO
     // Determines if the given register matches this one.
     template<typename Reg>
-    requires(IsRegister<Reg>)
     constexpr static bool isThis = [] {
         return std::is_same_v<typename Reg::access, access> && Addr == Reg::Addr;
     }();
 #else
     // Determines if the given register matches this one.
     template<typename Reg>
-    requires(IsRegister<Reg>)
     constexpr static bool isThis = [] {
         return Addr == Reg::Addr;
     }();
 #endif // FUNREG_ENABLE_EXTERNAL_IO
 
     Register() = delete;
+
+    using type = T;
 };
 
 /**
@@ -329,7 +251,6 @@ private:
  *     using LED_RED = RegisterMask<GPIO_OUT, (1 << 2)>;
  */
 template<typename Reg, typename Reg::type Mask>
-requires IsRegister<Reg>
 struct RegisterMask
 {
     using T = typename Reg::type;
@@ -452,7 +373,6 @@ struct RegisterMask
  * @tparam value The value to be used for the given Mask.
  */
 template<typename Mask, Mask::T value>
-requires(IsRegisterMask<Mask>)
 struct RegisterMaskValue
 {
     /**
@@ -486,7 +406,6 @@ struct RegisterMaskValue
  * each register.
  */
 template<typename... Registers>
-requires(IsRegister<Registers>, ...)
 class RegisterGroup
 {
 public:
@@ -496,8 +415,6 @@ public:
      * only written once.
      */
     template<typename... Masks>
-    requires((IsRegisterMask<Masks>, ...) &&
-             (UsesSomeRegister<Masks, Registers...>, ...))
     static void set() {
         apply<Masks...>([](auto r, auto m) { return r | m; });
     }
@@ -508,8 +425,6 @@ public:
      * Only reads and writes each register once; see set().
      */
     template<typename... Masks>
-    requires((IsRegisterMask<Masks>, ...) &&
-             (UsesSomeRegister<Masks, Registers...>, ...))
     static void clear() {
         apply<Masks...>([](auto r, auto m) { return r & ~m; });
     }
@@ -520,8 +435,6 @@ public:
      * Only reads and writes each register once; see set().
      */
     template<typename... Masks>
-    requires((IsRegisterMask<Masks>, ...) &&
-             (UsesSomeRegister<Masks, Registers...>, ...))
     static void toggle() {
         apply<Masks...>([](auto r, auto m) { return r ^ m; });
     }
@@ -540,8 +453,6 @@ public:
 
 private:
     template<typename... Masks>
-    requires((IsRegisterMask<Masks>, ...) &&
-             (UsesSomeRegister<Masks, Registers...>, ...))
     static void apply(auto fn) {
         (Registers::template apply<Masks...>(fn), ...);
     }
@@ -554,7 +465,6 @@ private:
  * register.
  */
 template<typename... RegMasks>
-requires(IsRegisterMask<RegMasks>, ...)
 constexpr auto Masks = (RegMasks::mask | ...);
 
 #ifdef FUNREG_ENABLE_EXTERNAL_IO
@@ -591,3 +501,4 @@ using MemRegister = Register<T, Addr>;
 } // namespace fr
 
 #endif // FUNCTIONAL_REGISTER_IO_H
+