[libc][math][c++23] Add fmodbf16 math function (#155575)

krishna2803 · web-flow · commit 96b1dfb57fc8 · 2025-09-03T22:20:07.000+05:30
This PR adds fmodbf16 basic math function for BFloat16 type along with
the tests.

---------

Signed-off-by: Krishna Pandey &lt;kpandey81930@gmail.com&gt;
diff --git a/libc/config/baremetal/aarch64/entrypoints.txt b/libc/config/baremetal/aarch64/entrypoints.txt
@@ -788,6 +788,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fminimum_magbf16
   libc.src.math.fminimum_mag_numbf16
   libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
   libc.src.math.frexpbf16
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
diff --git a/libc/config/baremetal/arm/entrypoints.txt b/libc/config/baremetal/arm/entrypoints.txt
@@ -791,6 +791,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fminimum_magbf16
   libc.src.math.fminimum_mag_numbf16
   libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
   libc.src.math.frexpbf16
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
diff --git a/libc/config/baremetal/riscv/entrypoints.txt b/libc/config/baremetal/riscv/entrypoints.txt
@@ -791,6 +791,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fminimum_magbf16
   libc.src.math.fminimum_mag_numbf16
   libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
   libc.src.math.frexpbf16
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
diff --git a/libc/config/darwin/aarch64/entrypoints.txt b/libc/config/darwin/aarch64/entrypoints.txt
@@ -621,6 +621,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fminimum_magbf16
   libc.src.math.fminimum_mag_numbf16
   libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
   libc.src.math.frexpbf16
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
diff --git a/libc/config/darwin/x86_64/entrypoints.txt b/libc/config/darwin/x86_64/entrypoints.txt
@@ -264,6 +264,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fminimum_magbf16
   libc.src.math.fminimum_mag_numbf16
   libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
   libc.src.math.frexpbf16
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
diff --git a/libc/config/gpu/amdgpu/entrypoints.txt b/libc/config/gpu/amdgpu/entrypoints.txt
@@ -647,6 +647,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fminimum_magbf16
   libc.src.math.fminimum_mag_numbf16
   libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
   libc.src.math.frexpbf16
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
diff --git a/libc/config/gpu/nvptx/entrypoints.txt b/libc/config/gpu/nvptx/entrypoints.txt
@@ -649,6 +649,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fminimum_magbf16
   libc.src.math.fminimum_mag_numbf16
   libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
   libc.src.math.frexpbf16
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
@@ -876,6 +876,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fminimum_magbf16
   libc.src.math.fminimum_mag_numbf16
   libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
   libc.src.math.frexpbf16
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
diff --git a/libc/config/linux/arm/entrypoints.txt b/libc/config/linux/arm/entrypoints.txt
@@ -491,6 +491,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fminimum_magbf16
   libc.src.math.fminimum_mag_numbf16
   libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
   libc.src.math.frexpbf16
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
@@ -894,6 +894,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fminimum_magbf16
   libc.src.math.fminimum_mag_numbf16
   libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
   libc.src.math.frexpbf16
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
@@ -929,6 +929,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fminimum_magbf16
   libc.src.math.fminimum_mag_numbf16
   libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
   libc.src.math.frexpbf16
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
diff --git a/libc/config/windows/entrypoints.txt b/libc/config/windows/entrypoints.txt
@@ -337,6 +337,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fminimum_magbf16
   libc.src.math.fminimum_mag_numbf16
   libc.src.math.fminimum_numbf16
+  libc.src.math.fmodbf16
   libc.src.math.frexpbf16
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
diff --git a/libc/docs/headers/math/index.rst b/libc/docs/headers/math/index.rst
@@ -175,7 +175,7 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+------------------------+----------------------------+
 | fminimum_num     | |check|          | |check|         | |check|                | |check|              | |check|                | |check|                | 7.12.12.9              | F.10.9.5                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+------------------------+----------------------------+
-| fmod             | |check|          | |check|         | |check|                | |check|              | |check|                |                        | 7.12.10.1              | F.10.7.1                   |
+| fmod             | |check|          | |check|         | |check|                | |check|              | |check|                | |check|                | 7.12.10.1              | F.10.7.1                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+------------------------+----------------------------+
 | fmul             | N/A              | |check|         | |check|                | N/A                  | |check|\*              | N/A                    | 7.12.14.3              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+------------------------+----------------------------+
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
@@ -308,6 +308,7 @@ add_math_entrypoint_object(fmodf)
 add_math_entrypoint_object(fmodl)
 add_math_entrypoint_object(fmodf16)
 add_math_entrypoint_object(fmodf128)
+add_math_entrypoint_object(fmodbf16)
 
 add_math_entrypoint_object(frexp)
 add_math_entrypoint_object(frexpf)
diff --git a/libc/src/math/fmodbf16.h b/libc/src/math/fmodbf16.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for fmodbf16 ----------------------*- 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_FMODBF16_H
+#define LLVM_LIBC_SRC_MATH_FMODBF16_H
+
+#include "src/__support/macros/config.h"
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+bfloat16 fmodbf16(bfloat16 x, bfloat16 y);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_MATH_FMODBF16_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
@@ -4015,6 +4015,20 @@ add_entrypoint_object(
     libc.src.__support.FPUtil.generic.fmod
 )
 
+add_entrypoint_object(
+  fmodbf16
+  SRCS
+    fmodbf16.cpp
+  HDRS
+    ../fmodbf16.h
+  DEPENDS
+    libc.src.__support.common
+    libc.src.__support.macros.config
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.bfloat16
+    libc.src.__support.FPUtil.generic.fmod
+)
+
 add_entrypoint_object(
   fromfp
   SRCS
diff --git a/libc/src/math/generic/fmodbf16.cpp b/libc/src/math/generic/fmodbf16.cpp
@@ -0,0 +1,21 @@
+//===-- Implementation of fmodbf16 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/fmodbf16.h"
+#include "src/__support/FPUtil/bfloat16.h"
+#include "src/__support/FPUtil/generic/FMod.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(bfloat16, fmodbf16, (bfloat16 x, bfloat16 y)) {
+  return fputil::generic::FMod<bfloat16>::eval(x, y);
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/src/math/exhaustive/CMakeLists.txt b/libc/test/src/math/exhaustive/CMakeLists.txt
@@ -377,6 +377,22 @@ add_fp_unittest(
     -lpthread
 )
 
+add_fp_unittest(
+  fmodbf16_test
+  NO_RUN_POSTBUILD
+  NEED_MPFR
+  SUITE
+    libc_math_exhaustive_tests
+  SRCS
+    fmodbf16_test.cpp
+  DEPENDS
+    .exhaustive_test
+    libc.src.math.fmodbf16
+    libc.src.__support.FPUtil.bfloat16
+  LINK_LIBRARIES
+    -lpthread
+)
+
 add_fp_unittest(
   coshf_test
   NO_RUN_POSTBUILD
diff --git a/libc/test/src/math/exhaustive/fmodbf16_test.cpp b/libc/test/src/math/exhaustive/fmodbf16_test.cpp
@@ -0,0 +1,42 @@
+//===-- Exhaustive test for fmodbf16 --------------------------------------===//
+//
+// 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 "exhaustive_test.h"
+#include "src/__support/FPUtil/bfloat16.h"
+#include "src/math/fmodbf16.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
+
+using LlvmLibcFmodf16ExhaustiveTest =
+    LlvmLibcBinaryOpExhaustiveMathTest<bfloat16, mpfr::Operation::Fmod,
+                                       LIBC_NAMESPACE::fmodbf16>;
+
+// range: [0, inf]
+static constexpr uint16_t POS_START = 0x0000U;
+static constexpr uint16_t POS_STOP = 0x7f80U;
+
+// range: [-0, -inf]
+static constexpr uint16_t NEG_START = 0x8000U;
+static constexpr uint16_t NEG_STOP = 0xff80U;
+
+TEST_F(LlvmLibcFmodf16ExhaustiveTest, PostivePositiveRange) {
+  test_full_range_all_roundings(POS_START, POS_STOP, POS_START, POS_STOP);
+}
+
+TEST_F(LlvmLibcFmodf16ExhaustiveTest, PostiveNegativeRange) {
+  test_full_range_all_roundings(POS_START, POS_STOP, NEG_START, NEG_STOP);
+}
+
+TEST_F(LlvmLibcFmodf16ExhaustiveTest, NegativePositiveRange) {
+  test_full_range_all_roundings(NEG_START, NEG_STOP, POS_START, POS_STOP);
+}
+
+TEST_F(LlvmLibcFmodf16ExhaustiveTest, NegativeNegativeRange) {
+  test_full_range_all_roundings(NEG_START, NEG_STOP, NEG_START, NEG_STOP);
+}
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
@@ -4503,6 +4503,23 @@ add_fp_unittest(
   UNIT_TEST_ONLY
 )
 
+add_fp_unittest(
+  fmodbf16_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    fmodbf16_test.cpp
+  HDRS
+    FModTest.h
+  DEPENDS
+    libc.hdr.fenv_macros
+    libc.src.errno.errno
+    libc.src.math.fmodbf16
+    libc.src.__support.FPUtil.bfloat16
+    libc.src.__support.FPUtil.fenv_impl
+  UNIT_TEST_ONLY
+)
+
 add_fp_unittest(
   coshf_test
   SUITE
diff --git a/libc/test/src/math/smoke/FModTest.h b/libc/test/src/math/smoke/FModTest.h
diff --git a/libc/test/src/math/smoke/fmodbf16_test.cpp b/libc/test/src/math/smoke/fmodbf16_test.cpp
