Fix MSVC build

2 files changed, 45 insertions, 4 deletions

diff --git a/include/chilbert/detail/MultiBitVec.hpp b/include/chilbert/detail/MultiBitVec.hpp
index 9053a04..bf1802c 100644
--- a/include/chilbert/detail/MultiBitVec.hpp
+++ b/include/chilbert/detail/MultiBitVec.hpp
@@ -165,7 +165,7 @@ public:
   size_t find_first() const
   {
     for (size_t i = 0; i < num_racks(); ++i) {
-      const int j = chilbert::detail::find_first(rack(i));
+      const auto j = chilbert::detail::find_first(rack(i));
       if (j) {
         return (i * bits_per_rack) + static_cast<size_t>(j);
       }
diff --git a/include/chilbert/detail/operations.hpp b/include/chilbert/detail/operations.hpp
index ba9971e..5dd59db 100644
--- a/include/chilbert/detail/operations.hpp
+++ b/include/chilbert/detail/operations.hpp
@@ -8,6 +8,11 @@
 #include "chilbert/detail/traits.hpp"
 #include "chilbert/operators.hpp"
 
+#ifdef _MSC_VER
+#  include <immintrin.h>
+#  include <intrin.h>
+#endif
+
 #include <cassert>
 #include <climits>
 #include <cstddef>
@@ -86,25 +91,59 @@ set_bit(T& field, const size_t index, const bool value)
   field.set(index, value);
 }
 
+#ifdef _MSC_VER
+
+inline uint32_t
+pop_count(const uint32_t field)
+{
+  return __popcnt(field);
+}
+
+inline uint64_t
+pop_count(const uint64_t field)
+{
+  return __popcnt64(field);
+}
+
+#else
+
 /// Return 1 + the index of the least significant 1-bit of `field`, or zero
 template<typename T>
 inline int
-pop_count(const T& field);
+pop_count(const T field);
 
 template<>
 inline int
-pop_count<unsigned long>(const unsigned long& field)
+pop_count<unsigned long>(const unsigned long field)
 {
   return __builtin_popcountl(field);
 }
 
 template<>
 inline int
-pop_count<unsigned long long>(const unsigned long long& field)
+pop_count<unsigned long long>(const unsigned long long field)
 {
   return __builtin_popcountll(field);
 }
 
+#endif
+
+#ifdef _MSC_VER
+
+inline uint32_t
+find_first(const uint32_t field)
+{
+  return field ? 1U + _tzcnt_u32(field) : 0U;
+}
+
+inline uint64_t
+find_first(const uint64_t field)
+{
+  return field ? 1U + _tzcnt_u64(field) : 0U;
+}
+
+#else
+
 /// Return 1 + the index of the least significant 1-bit of `field`, or zero
 template<typename T>
 inline int
@@ -124,6 +163,8 @@ find_first<unsigned long long>(const unsigned long long field)
   return __builtin_ffsll(static_cast<long long>(field));
 }
 
+#endif
+
 /// Calculates the Gray Code of `value` in place
 template<typename T>
 std::enable_if_t<is_bitvec_v<T>>