[libc] [llvm] [libc][stdfix] Add round functions for fixed point types. (PR #81994)

[via llvm-commits]

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@@ -19,6 +21,36 @@
 
 namespace LIBC_NAMESPACE::fixed_point {
 
+// Bit-wise operations are not available for fixed point types yet.
+template <typename T>
+LIBC_INLINE constexpr cpp::enable_if_t<cpp::is_fixed_point_v<T>, T>
+bit_and(T x, T y) {
+  using BitType = typename FXRep<T>::StorageType;
+  static_assert(sizeof(BitType) * CHAR_BIT == sizeof(T) * CHAR_BIT);
+  BitType x_bit = cpp::bit_cast<BitType>(x);
+  BitType y_bit = cpp::bit_cast<BitType>(y);
+  return cpp::bit_cast<T, BitType>(x_bit & y_bit);
+}
+
+template <typename T>
+LIBC_INLINE constexpr cpp::enable_if_t<cpp::is_fixed_point_v<T>, T>
+bit_or(T x, T y) {
+  using BitType = typename FXRep<T>::StorageType;
+  static_assert(sizeof(BitType) * CHAR_BIT == FXRep<T>::TOTAL_LEN);
+  BitType x_bit = cpp::bit_cast<BitType>(x);
+  BitType y_bit = cpp::bit_cast<BitType>(y);
+  return cpp::bit_cast<T, BitType>(x_bit | y_bit);
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lntue wrote:

Added comments explaining the reason.

https://github.com/llvm/llvm-project/pull/81994