implement cuda::fp types

NVIDIA · Jan 29, 2025 · ea48870 · ea48870
1 parent d5d3aa6
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diff --git a/libcudacxx/include/cuda/__floating_point/cast.h b/libcudacxx/include/cuda/__floating_point/cast.h
diff --git a/libcudacxx/include/cuda/__floating_point/config.h b/libcudacxx/include/cuda/__floating_point/config.h
diff --git a/libcudacxx/include/cuda/__floating_point/conv_rank_order.h b/libcudacxx/include/cuda/__floating_point/conv_rank_order.h
@@ -0,0 +1,89 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of libcu++, the C++ Standard Library for your entire system,
+// under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+// SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _CUDA___FLOATING_POINT_CONV_RANK_ORDER_H
+#define _CUDA___FLOATING_POINT_CONV_RANK_ORDER_H
+
+#include <cuda/std/detail/__config>
+
+#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
+#  pragma GCC system_header
+#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
+#  pragma clang system_header
+#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
+#  pragma system_header
+#endif // no system header
+
+#if _CCCL_STD_VER >= 2017
+
+_LIBCUDACXX_BEGIN_NAMESPACE_CUDA
+
+#  include <cuda/__floating_point/config.h>
+#  include <cuda/__floating_point/type_traits.h>
+#  include <cuda/std/__type_traits/is_same.h>
+
+enum class __fp_conv_rank_order
+{
+  __unordered,
+  __greater,
+  __equal,
+  __less,
+};
+
+template <class _To, class _From>
+_CCCL_NODISCARD _LIBCUDACXX_HIDE_FROM_ABI constexpr __fp_conv_rank_order __fp_make_conv_rank_order()
+{
+  using _FromConfig = __fp_make_config_from_t<_From>;
+  using _ToConfig   = __fp_make_config_from_t<_To>;
+
+  if constexpr (!_CUDA_VSTD::is_same_v<_FromConfig, __fp_invalid_config>
+                && !_CUDA_VSTD::is_same_v<_ToConfig, __fp_invalid_config>)
+  {
+    if constexpr (_ToConfig::__is_signed == _FromConfig::__is_signed)
+    {
+      if constexpr (_ToConfig::__exp_nbits == _FromConfig::__exp_nbits
+                    && _ToConfig::__mant_nbits == _FromConfig::__mant_nbits)
+      {
+#  if !defined(_LIBCUDACXX_HAS_NO_LONG_DOUBLE)
+        // If the representations are the same, long double always has the higher subrank
+        if constexpr (_CUDA_VSTD::is_same_v<_ToConfig, __fp_long_double_config>
+                      && !_CUDA_VSTD::is_same_v<_FromConfig, __fp_long_double_config>)
+        {
+          return __fp_conv_rank_order::__greater;
+        }
+        else if constexpr (!_CUDA_VSTD::is_same_v<_ToConfig, __fp_long_double_config>
+                           && _CUDA_VSTD::is_same_v<_FromConfig, __fp_long_double_config>)
+        {
+          return __fp_conv_rank_order::__less;
+        }
+#  endif // !_LIBCUDACXX_HAS_NO_LONG_DOUBLE
+        return __fp_conv_rank_order::__equal;
+      }
+      else if constexpr (_ToConfig::__exp_nbits >= _FromConfig::__exp_nbits
+                         && _ToConfig::__mant_nbits >= _FromConfig::__mant_nbits)
+      {
+        return __fp_conv_rank_order::__greater;
+      }
+      else if constexpr (_ToConfig::__exp_nbits <= _FromConfig::__exp_nbits
+                         && _ToConfig::__mant_nbits <= _FromConfig::__mant_nbits)
+      {
+        return __fp_conv_rank_order::__less;
+      }
+    }
+  }
+
+  return __fp_conv_rank_order::__unordered;
+}
+
+_LIBCUDACXX_END_NAMESPACE_CUDA
+
+#endif // _CCCL_STD_VER >= 2017
+
+#endif // _CUDA___FLOATING_POINT_CONV_RANK_ORDER_H