[libc][math][c23] Add {getpayload,setpayload,setpayloadsig}f16 C23 math functions (#95159)

Part of #93566.

9 files changed, 204 insertions, 0 deletions

diff --git a/libc/src/__support/FPUtil/BasicOperations.h b/libc/src/__support/FPUtil/BasicOperations.h
index beb8e48..17eee7b 100644
--- a/libc/src/__support/FPUtil/BasicOperations.h
+++ b/libc/src/__support/FPUtil/BasicOperations.h
@@ -265,6 +265,48 @@ totalordermag(T x, T y) {
   return FPBits<T>(x).abs().uintval() <= FPBits<T>(y).abs().uintval();
 }
 
+template <typename T>
+LIBC_INLINE cpp::enable_if_t<cpp::is_floating_point_v<T>, T> getpayload(T x) {
+  using FPBits = FPBits<T>;
+  FPBits x_bits(x);
+
+  if (!x_bits.is_nan())
+    return T(-1.0);
+
+  return T(x_bits.uintval() & (FPBits::FRACTION_MASK >> 1));
+}
+
+template <bool IsSignaling, typename T>
+LIBC_INLINE cpp::enable_if_t<cpp::is_floating_point_v<T>, bool>
+setpayload(T &res, T pl) {
+  using FPBits = FPBits<T>;
+  FPBits pl_bits(pl);
+
+  // Signaling NaNs don't have the mantissa's MSB set to 1, so they need a
+  // non-zero payload to distinguish them from infinities.
+  if (!IsSignaling && pl_bits.is_zero()) {
+    res = FPBits::quiet_nan(Sign::POS).get_val();
+    return false;
+  }
+
+  int pl_exp = pl_bits.get_exponent();
+
+  if (pl_bits.is_neg() || pl_exp < 0 || pl_exp >= FPBits::FRACTION_LEN - 1 ||
+      ((pl_bits.get_mantissa() << pl_exp) & FPBits::FRACTION_MASK) != 0) {
+    res = T(0.0);
+    return true;
+  }
+
+  using StorageType = typename FPBits::StorageType;
+  StorageType v(pl_bits.get_explicit_mantissa() >> (FPBits::SIG_LEN - pl_exp));
+
+  if constexpr (IsSignaling)
+    res = FPBits::signaling_nan(Sign::POS, v).get_val();
+  else
+    res = FPBits::quiet_nan(Sign::POS, v).get_val();
+  return false;
+}
+
 } // namespace fputil
 } // namespace LIBC_NAMESPACE
 
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index 4472367..92e0cd2 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -210,6 +210,8 @@ add_math_entrypoint_object(fromfpxl)
 add_math_entrypoint_object(fromfpxf16)
 add_math_entrypoint_object(fromfpxf128)
 
+add_math_entrypoint_object(getpayloadf16)
+
 add_math_entrypoint_object(hypot)
 add_math_entrypoint_object(hypotf)
 
@@ -350,6 +352,10 @@ add_math_entrypoint_object(scalbnf)
 add_math_entrypoint_object(scalbnl)
 add_math_entrypoint_object(scalbnf128)
 
+add_math_entrypoint_object(setpayloadf16)
+
+add_math_entrypoint_object(setpayloadsigf16)
+
 add_math_entrypoint_object(sincos)
 add_math_entrypoint_object(sincosf)
 
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index aa0069d..f509b97 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -3603,6 +3603,45 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
+  getpayloadf16
+  SRCS
+    getpayloadf16.cpp
+  HDRS
+    ../getpayloadf16.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.basic_operations
+  COMPILE_OPTIONS
+    -O3
+)
+
+add_entrypoint_object(
+  setpayloadf16
+  SRCS
+    setpayloadf16.cpp
+  HDRS
+    ../setpayloadf16.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.basic_operations
+  COMPILE_OPTIONS
+    -O3
+)
+
+add_entrypoint_object(
+  setpayloadsigf16
+  SRCS
+    setpayloadsigf16.cpp
+  HDRS
+    ../setpayloadsigf16.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.basic_operations
+  COMPILE_OPTIONS
+    -O3
+)
+
+add_entrypoint_object(
   f16fmaf
   SRCS
     f16fmaf.cpp
diff --git a/libc/src/math/generic/getpayloadf16.cpp b/libc/src/math/generic/getpayloadf16.cpp
new file mode 100644
index 0000000..0923226
--- /dev/null
+++ b/libc/src/math/generic/getpayloadf16.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of getpayloadf16 function --------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/getpayloadf16.h"
+#include "src/__support/FPUtil/BasicOperations.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, getpayloadf16, (const float16 *x)) {
+  return fputil::getpayload(*x);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/math/generic/setpayloadf16.cpp b/libc/src/math/generic/setpayloadf16.cpp
new file mode 100644
index 0000000..98fc239
--- /dev/null
+++ b/libc/src/math/generic/setpayloadf16.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of setpayloadf16 function --------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/setpayloadf16.h"
+#include "src/__support/FPUtil/BasicOperations.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(int, setpayloadf16, (float16 * res, float16 pl)) {
+  return static_cast<int>(fputil::setpayload</*IsSignaling=*/false>(*res, pl));
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/math/generic/setpayloadsigf16.cpp b/libc/src/math/generic/setpayloadsigf16.cpp
new file mode 100644
index 0000000..c79620f
--- /dev/null
+++ b/libc/src/math/generic/setpayloadsigf16.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of setpayloadsigf16 function -----------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/setpayloadsigf16.h"
+#include "src/__support/FPUtil/BasicOperations.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(int, setpayloadsigf16, (float16 * res, float16 pl)) {
+  return static_cast<int>(fputil::setpayload</*IsSignaling=*/true>(*res, pl));
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/math/getpayloadf16.h b/libc/src/math/getpayloadf16.h
new file mode 100644
index 0000000..1349dfd
--- /dev/null
+++ b/libc/src/math/getpayloadf16.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for getpayloadf16 -----------------*- 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_MATH_GETPAYLOADF16_H
+#define LLVM_LIBC_SRC_MATH_GETPAYLOADF16_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 getpayloadf16(const float16 *x);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_GETPAYLOADF16_H
diff --git a/libc/src/math/setpayloadf16.h b/libc/src/math/setpayloadf16.h
new file mode 100644
index 0000000..8705e28
--- /dev/null
+++ b/libc/src/math/setpayloadf16.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for setpayloadf16 -----------------*- 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_MATH_SETPAYLOADF16_H
+#define LLVM_LIBC_SRC_MATH_SETPAYLOADF16_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+int setpayloadf16(float16 *res, float16 pl);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_SETPAYLOADF16_H
diff --git a/libc/src/math/setpayloadsigf16.h b/libc/src/math/setpayloadsigf16.h
new file mode 100644
index 0000000..ee9bc38
--- /dev/null
+++ b/libc/src/math/setpayloadsigf16.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for setpayloadsigf16 --------------*- 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_MATH_SETPAYLOADSIGF16_H
+#define LLVM_LIBC_SRC_MATH_SETPAYLOADSIGF16_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+int setpayloadsigf16(float16 *res, float16 pl);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_SETPAYLOADSIGF16_H