[libc-commits] [libc] [libc] Float128 Emulation in LLVM libc (PR #200565)

[via libc-commits]

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@@ -0,0 +1,161 @@
+//===-- Definition for Float128 data type -----------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_FPUTIL_FLOAT128_H
+#define LLVM_LIBC_SRC___SUPPORT_FPUTIL_FLOAT128_H
+
+#include "hdr/stdint_proxy.h"
+#include "src/__support/CPP/type_traits.h"
+#include "src/__support/FPUtil/cast.h"
+#include "src/__support/FPUtil/comparison_operations.h"
+#include "src/__support/FPUtil/dyadic_float.h"
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/FPUtil/generic/div.h"
+#include "src/__support/FPUtil/generic/mul.h"
+#include "src/__support/macros/attributes.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/uint128.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace fputil {
+
+struct Float128 {
+  UInt128 bits;
+
+  LIBC_INLINE Float128() = default;
+  LIBC_INLINE constexpr Float128(const Float128 &) = default;
+  LIBC_INLINE constexpr Float128(Float128 &&) = default;
+  LIBC_INLINE constexpr Float128 &operator=(const Float128 &) = default;
+  LIBC_INLINE constexpr Float128 &operator=(Float128 &&) = default;
+
+  // Floating point type and integer type
+  template <typename T>
+  LIBC_INLINE constexpr explicit Float128(T value) : bits(0U) {
+    if constexpr (cpp::is_floating_point_v<T>) {
+      bits = fputil::cast<Float128>(value).bits;
+    } else if constexpr (cpp::is_integral_v<T>) {
+      Sign sign = Sign::POS;
+      auto unsigned_value = static_cast<cpp::make_unsigned_t<T>>(value);
+
+      if constexpr (cpp::is_signed_v<T>) {
+        if (value < 0) {
+          sign = Sign::NEG;
+          unsigned_value = -unsigned_value;
+        }
+      }
+
+      fputil::DyadicFloat<FPBits<Float128>::STORAGE_LEN> xd(sign, 0,
+                                                            unsigned_value);
+      bits = xd.template as<Float128, /*ShouldSignalExceptions=*/true>().bits;
+
+    } else if constexpr (cpp::is_convertible_v<T, Float128>) {
+      bits = value.operator Float128().bits;
+    } else {
+      bits = fputil::cast<Float128>(static_cast<float>(value)).bits;
+    }
+  }
+
+  template <typename T, cpp::enable_if_t<cpp::is_floating_point_v<T> &&
+                                             !cpp::is_same_v<T, Float128>,
+                                         int> = 0>
+  LIBC_INLINE LIBC_CONSTEXPR_DEFAULT operator T() const {
+    return fputil::cast<T>(*this);
+  }
+
+  template <typename T, cpp::enable_if_t<cpp::is_integral_v<T>, int> = 0>
+  LIBC_INLINE constexpr explicit operator T() const {
+    FPBits<Float128> x_bits(*this);
+    // Raise FE_INVALID for inf and NaN
+    if (x_bits.is_inf_or_nan()) {
+      raise_except_if_required(FE_INVALID);
+    }
+    int x_bits_exp =
+        x_bits.get_explicit_exponent() - FPBits<Float128>::FRACTION_LEN;
+    // sign * 2^(exp-bias) * mantissa
+    DyadicFloat<FPBits<Float128>::STORAGE_LEN> xd(
+        x_bits.sign(), x_bits_exp, x_bits.get_explicit_mantissa());
+    return static_cast<T>(xd.as_mantissa_type());
----------------
Sukumarsawant wrote:

added both in https://github.com/llvm/llvm-project/pull/211593

https://github.com/llvm/llvm-project/pull/200565