Start building wrapper of GCC decimal32

include/boost/decimal/charconv.hpp

@@ -780,11 +780,11 @@ BOOST_DECIMAL_CONSTEXPR auto to_chars_impl(char* first, char* last, TargetDecima
     }
 
     auto abs_value = abs(value);
-    constexpr auto max_fractional_value = impl::decimal_val_v<TargetDecimalType> < 64 ?  TargetDecimalType{1, 7} :
-                                                          impl::decimal_val_v<TargetDecimalType> < 128 ? TargetDecimalType{1, 16} :
-                                                                                                         TargetDecimalType{1, 34};
+    const auto max_fractional_value = impl::decimal_val_v<TargetDecimalType> < 64 ?  TargetDecimalType{1, 7} :
+                                      impl::decimal_val_v<TargetDecimalType> < 128 ? TargetDecimalType{1, 16} :
+                                      TargetDecimalType{1, 34};
 
-    constexpr auto min_fractional_value = TargetDecimalType{1, -4};
+    const auto min_fractional_value = TargetDecimalType{1, -4};
 
     // Unspecified precision so we always go with the shortest representation
     if (precision == -1)

include/boost/decimal/decimal32.hpp

@@ -143,6 +143,9 @@ BOOST_DECIMAL_EXPORT class decimal32 final // NOLINT(cppcoreguidelines-special-m
 
     std::uint32_t bits_ {};
 
+#ifdef BOOST_DECIMAL_DEBUG_ACCESSORS
+public:
+#endif
     // Returns the un-biased (quantum) exponent
     constexpr auto unbiased_exponent() const noexcept -> exponent_type ;
 
@@ -153,6 +156,12 @@ BOOST_DECIMAL_EXPORT class decimal32 final // NOLINT(cppcoreguidelines-special-m
     constexpr auto full_significand() const noexcept -> significand_type ;
     constexpr auto isneg() const noexcept -> bool;
 
+    // Returns a complete struct so we don't have to decode multiple times
+    constexpr auto to_components() const noexcept -> detail::decimal32_components;
+
+#ifdef BOOST_DECIMAL_DEBUG_ACCESSORS
+private:
+#endif
     // Attempts conversion to integral type:
     // If this is nan sets errno to EINVAL and returns 0
     // If this is not representable sets errno to ERANGE and returns 0
@@ -1444,18 +1453,62 @@ constexpr auto decimal32::full_significand() const noexcept -> significand_type
     return significand;
 }
 
+constexpr auto decimal32::isneg() const noexcept -> bool
+{
+    return static_cast<bool>(bits_ & detail::d32_sign_mask);
+}
+
+constexpr auto decimal32::to_components() const noexcept -> detail::decimal32_components
+{
+    detail::decimal32_components components {};
+
+    exponent_type expval {};
+    significand_type significand {};
+
+    const auto comb_bits {(bits_ & detail::d32_comb_11_mask)};
+
+    switch (comb_bits)
+    {
+        case detail::d32_comb_11_mask:
+            // bits 2 and 3 are the exp part of the combination field
+            expval = (bits_ & detail::d32_comb_11_exp_bits) >> (detail::d32_significand_bits + 1);
+            // Only need the one bit of T because the other 3 are implied
+            significand = (bits_ & detail::d32_comb_11_significand_bits) == detail::d32_comb_11_significand_bits ?
+                          UINT32_C(0b1001'0000000000'0000000000) :
+                          UINT32_C(0b1000'0000000000'0000000000);
+            break;
+        case detail::d32_comb_10_mask:
+            expval = UINT32_C(0b10000000);
+            // Last three bits in the combination field, so we need to shift past the exp field
+            // which is next
+            significand |= (bits_ & detail::d32_comb_00_01_10_significand_bits) >> detail::d32_exponent_bits;
+            break;
+        case detail::d32_comb_01_mask:
+            expval = UINT32_C(0b01000000);
+            significand |= (bits_ & detail::d32_comb_00_01_10_significand_bits) >> detail::d32_exponent_bits;
+            break;
+        case 0U:
+            significand |= (bits_ & detail::d32_comb_00_01_10_significand_bits) >> detail::d32_exponent_bits;
+            break;
+    }
+
+    significand |= (bits_ & detail::d32_significand_mask);
+    expval |= (bits_ & detail::d32_exponent_mask) >> detail::d32_significand_bits;
+
+    components.sig = significand;
+    components.exp = static_cast<decimal32::biased_exponent_type>(expval) - detail::bias_v<decimal32>;
+    components.sign = bits_ & detail::d32_sign_mask;
+
+    return components;
+}
+
 template <typename T>
 constexpr auto decimal32::edit_significand(T sig) noexcept
     BOOST_DECIMAL_REQUIRES_RETURN(detail::is_integral_v, T, void)
 {
     *this = decimal32(sig, this->biased_exponent(), this->isneg());
 }
 
-constexpr auto decimal32::isneg() const noexcept -> bool
-{
-    return static_cast<bool>(bits_ & detail::d32_sign_mask);
-}
-
 // Allows changing the sign even on nans and infs
 constexpr auto decimal32::edit_sign(bool sign) noexcept -> void
 {

include/boost/decimal/detail/cmath/acosh.hpp

@@ -54,7 +54,7 @@ constexpr auto acosh_impl(T x) noexcept
     #endif
     else
     {
-        constexpr T one  { 1, 0 };
+        const T one  { 1, 0 };
 
         if (x < one)
         {

include/boost/decimal/detail/cmath/asinh.hpp

@@ -35,8 +35,8 @@ constexpr auto asinh_impl(T x) noexcept
     {
         // Use (parts of) the implementation of asinh from Boost.Math.
 
-        constexpr T zero { 0, 0 };
-        constexpr T one  { 1, 0 };
+        const T zero { 0, 0 };
+        const T one  { 1, 0 };
 
         if (x < zero)
         {

include/boost/decimal/detail/cmath/atan.hpp

@@ -53,7 +53,7 @@ constexpr auto atan_impl(T x) noexcept
     #endif
     else
     {
-        constexpr T one { 1 };
+        const T one { 1 };
 
         if (x <= T { 48 })
         {

include/boost/decimal/detail/cmath/atan2.hpp

@@ -103,7 +103,7 @@ constexpr auto atan2_impl(T y, T x) noexcept
     }
     else if (fpcx == FP_INFINITE && !signx && isfinitey)
     {
-        constexpr T zero { 0, 0 };
+        const T zero { 0, 0 };
 
         result = signy ? -zero : zero;
     }

include/boost/decimal/detail/cmath/atanh.hpp

@@ -33,12 +33,12 @@ constexpr auto atanh_impl(T x) noexcept
     }
     else
     {
-        constexpr T zero { 0, 0 };
+        const T zero { 0, 0 };
 
         const auto b_neg = x < zero;
         const auto xx = abs(x);
 
-        constexpr T one  { 1, 0 };
+        const T one  { 1, 0 };
 
         if (xx > one)
         {

include/boost/decimal/detail/cmath/ceil.hpp

@@ -29,8 +29,8 @@ constexpr auto ceil BOOST_DECIMAL_PREVENT_MACRO_SUBSTITUTION (T val) noexcept
 {
     using DivType = typename T::significand_type;
 
-    constexpr T zero {0, 0};
-    constexpr T one {1, 0};
+    const T zero {0, 0};
+    const T one {1, 0};
     const auto fp {fpclassify(val)};
 
     switch (fp)

include/boost/decimal/detail/cmath/cos.hpp

@@ -107,7 +107,7 @@ constexpr auto cos_impl(T x) noexcept
         }
         else
         {
-            constexpr T one { 1 };
+            const T one { 1 };
 
             result = one;
         }

include/boost/decimal/detail/cmath/cosh.hpp

@@ -29,8 +29,8 @@ constexpr auto cosh_impl(T x) noexcept
 {
     const auto fpc = fpclassify(x);
 
-    constexpr T zero { 0, 0 };
-    constexpr T one  { 1, 0 };
+    const T zero { 0, 0 };
+    const T one  { 1, 0 };
 
     auto result = zero;
 

include/boost/decimal/detail/cmath/ellint_1.hpp

@@ -34,7 +34,7 @@ template <typename T>
 constexpr auto ellint_1_impl(T m, T phi) noexcept
     BOOST_DECIMAL_REQUIRES(detail::is_decimal_floating_point_v, T)
 {
-  constexpr T one { 1 };
+  const T one { 1 };
 
   T result { };
 
@@ -47,7 +47,7 @@ constexpr auto ellint_1_impl(T m, T phi) noexcept
   }
   else if((fpc_phi == FP_ZERO) && (fpc_m == FP_NORMAL))
   {
-    constexpr T zero { 0 };
+    const T zero { 0 };
 
     result = zero;
   }
@@ -132,7 +132,7 @@ template <typename T>
 constexpr auto comp_ellint_1_impl(T m) noexcept
     BOOST_DECIMAL_REQUIRES(detail::is_decimal_floating_point_v, T)
 {
-  constexpr T one  { 1 };
+  const T one  { 1 };
 
   T result { };
 
@@ -152,7 +152,7 @@ constexpr auto comp_ellint_1_impl(T m) noexcept
   }
   else
   {
-    constexpr T zero { 0 };
+    const T zero { 0 };
 
     T Fpm { };
 

include/boost/decimal/detail/cmath/ellint_2.hpp

@@ -34,7 +34,7 @@ template <typename T>
 constexpr auto ellint_2_impl(T m, T phi) noexcept
     BOOST_DECIMAL_REQUIRES(detail::is_decimal_floating_point_v, T)
 {
-  constexpr T one { 1 };
+  const T one { 1 };
 
   T result { };
 
@@ -47,7 +47,7 @@ constexpr auto ellint_2_impl(T m, T phi) noexcept
   }
   else if((fpc_phi == FP_ZERO) && (fpc_m == FP_NORMAL))
   {
-    constexpr T zero { 0 };
+    const T zero { 0 };
 
     result = zero;
   }
@@ -129,7 +129,7 @@ template <typename T>
 constexpr auto comp_ellint_2_impl(T m) noexcept
     BOOST_DECIMAL_REQUIRES(detail::is_decimal_floating_point_v, T)
 {
-  constexpr T one  { 1 };
+  const T one  { 1 };
 
   T result { };
 
@@ -149,7 +149,7 @@ constexpr auto comp_ellint_2_impl(T m) noexcept
   }
   else
   {
-    constexpr T zero { 0 };
+    const T zero { 0 };
 
     T Fpm { };
     T Km  { };

include/boost/decimal/detail/cmath/erf.hpp

@@ -102,7 +102,7 @@ constexpr auto erf_series_near_zero_sum(const T &x) noexcept -> T
 template <BOOST_DECIMAL_DECIMAL_FLOATING_TYPE T>
 constexpr auto erf_calc_impl(T z, bool invert) noexcept -> T
 {
-    constexpr T zero {0, 0};
+    const T zero {0, 0};
 
     if (z < zero)
     {
@@ -232,7 +232,7 @@ constexpr auto erf_calc_impl(T z, bool invert) noexcept -> T
                 T{UINT64_C(8978713707780316114), -22}
             };
 
-            constexpr T one_and_half {15, -1};
+            const T one_and_half {15, -1};
             result = Y + tools::evaluate_polynomial(P, T(z - one_and_half)) / tools::evaluate_polynomial(Q, T(z - one_and_half));
         }
         else if (z < T{45, -1})

include/boost/decimal/detail/cmath/exp.hpp

@@ -30,8 +30,8 @@ constexpr auto exp_impl(T x) noexcept
 {
     const auto fpc = fpclassify(x);
 
-    constexpr T zero { 0, 0 };
-    constexpr T one  { 1, 0 };
+    const T zero { 0, 0 };
+    const T one  { 1, 0 };
 
     auto result = zero;
 

include/boost/decimal/detail/cmath/expm1.hpp

@@ -29,8 +29,8 @@ constexpr auto expm1_impl(T x) noexcept
 {
     const auto fpc = fpclassify(x);
 
-    constexpr T zero { 0, 0 };
-    constexpr T one  { 1, 0 };
+    const T zero { 0, 0 };
+    const T one  { 1, 0 };
 
     auto result = zero;
 

include/boost/decimal/detail/cmath/fdim.hpp

@@ -23,7 +23,7 @@ BOOST_DECIMAL_EXPORT template <typename T>
 constexpr auto fdim(T x, T y) noexcept
     BOOST_DECIMAL_REQUIRES(detail::is_decimal_floating_point_v, T)
 {
-    constexpr T zero {0, 0};
+    const T zero {0, 0};
 
     #ifndef BOOST_DECIMAL_FAST_MATH
     if (isnan(x) || isinf(x))

include/boost/decimal/detail/cmath/floor.hpp

@@ -29,7 +29,7 @@ constexpr auto floor BOOST_DECIMAL_PREVENT_MACRO_SUBSTITUTION (T val) noexcept
 {
     using DivType = typename T::significand_type;
 
-    constexpr T zero {0, 0};
+    const T zero {0, 0};
     constexpr T neg_one {1, 0, true};
     const auto fp {fpclassify(val)};
 

include/boost/decimal/detail/cmath/fpclassify.hpp

@@ -23,7 +23,7 @@ BOOST_DECIMAL_EXPORT template <typename T>
 constexpr auto fpclassify BOOST_DECIMAL_PREVENT_MACRO_SUBSTITUTION (T rhs) noexcept
     BOOST_DECIMAL_REQUIRES_RETURN(detail::is_decimal_floating_point_v, T, int)
 {
-    constexpr T zero {0, 0};
+    const T zero {0, 0};
 
     #ifdef BOOST_DECIMAL_FAST_MATH
 

include/boost/decimal/detail/cmath/frexp.hpp

@@ -28,7 +28,7 @@ constexpr auto frexp_impl(T v, int* expon) noexcept
 {
     // This implementation of frexp follows closely that of eval_frexp
     // in Boost.Multiprecision's cpp_dec_float template class.
-    constexpr T zero { 0, 0 };
+    const T zero { 0, 0 };
 
     auto result_frexp = zero;
 

include/boost/decimal/detail/cmath/frexp10.hpp

@@ -28,7 +28,7 @@ namespace decimal {
 BOOST_DECIMAL_EXPORT template <BOOST_DECIMAL_DECIMAL_FLOATING_TYPE T>
 constexpr auto frexp10(T num, int* expptr) noexcept -> typename T::significand_type
 {
-    constexpr T zero {0, 0};
+    const T zero {0, 0};
 
     if (num == zero)
     {

include/boost/decimal/detail/cmath/hypot.hpp

@@ -28,7 +28,7 @@ namespace detail {
 template <BOOST_DECIMAL_DECIMAL_FLOATING_TYPE T>
 constexpr auto hypot_impl(T x, T y) noexcept
 {
-    constexpr T zero {0, 0};
+    const T zero {0, 0};
 
     if (abs(x) == zero
         #ifndef BOOST_DECIMAL_FAST_MATH

include/boost/decimal/detail/cmath/impl/ellint_impl.hpp

@@ -67,7 +67,7 @@ constexpr auto agm(T  phi,
 
   const bool phi_is_pi_half { phi == my_pi_half };
 
-  constexpr T one  { 1 };
+  const T one  { 1 };
 
   const bool has_e { ((pEm  != nullptr) || (pEpm != nullptr)) };
 
@@ -94,7 +94,7 @@ constexpr auto agm(T  phi,
   }
   else
   {
-    constexpr T zero { 0 };
+    const T zero { 0 };
     constexpr T half { 5 , -1 };
 
     T a0    { one };

include/boost/decimal/detail/cmath/impl/pow_impl.hpp

@@ -22,7 +22,7 @@ constexpr auto pow_n_impl(T b, UnsignedIntegralType p) noexcept -> std::enable_i
 {
     using local_unsigned_integral_type = UnsignedIntegralType;
 
-    constexpr T one { 1, 0 };
+    const T one { 1, 0 };
 
     T result { };
 
@@ -78,7 +78,7 @@ constexpr auto pow_n_impl(T b, UnsignedIntegralType p) noexcept -> std::enable_i
 template<typename T>
 constexpr auto pow_2_impl(int e2) noexcept -> std::enable_if_t<detail::is_decimal_floating_point_v<T>, T>
 {
-    constexpr T one { 1, 0 };
+    const T one { 1, 0 };
 
     T result { };