libc/src/__support/FPUtil/x86_64/nearest_integer.h

   1 //===--- Round floating point to nearest integer on x86-64 ------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_LIBC_SRC_SUPPORT_FPUTIL_X86_64_NEAREST_INTEGER_H
  10 #define LLVM_LIBC_SRC_SUPPORT_FPUTIL_X86_64_NEAREST_INTEGER_H
  11
  12 #include "src/__support/common.h"
  13 #include "src/__support/macros/properties/architectures.h"
  14
  15 #if !defined(LIBC_TARGET_ARCH_IS_X86_64)
  16 #error "Invalid include"
  17 #endif
  18
  19 #if !defined(__SSE4_2__)
  20 #error "SSE4.2 instruction set is not supported"
  21 #endif
  22
  23 #include <immintrin.h>
  24
  25 namespace __llvm_libc {
  26 namespace fputil {
  27
  28 LIBC_INLINE float nearest_integer(float x) {
  29   __m128 xmm = _mm_set_ss(x); // NOLINT
  30   __m128 ymm =
  31       _mm_round_ss(xmm, xmm, _MM_ROUND_NEAREST | _MM_FROUND_NO_EXC); // NOLINT
  32   return ymm[0];
  33 }
  34
  35 LIBC_INLINE double nearest_integer(double x) {
  36   __m128d xmm = _mm_set_sd(x); // NOLINT
  37   __m128d ymm =
  38       _mm_round_sd(xmm, xmm, _MM_ROUND_NEAREST | _MM_FROUND_NO_EXC); // NOLINT
  39   return ymm[0];
  40 }
  41
  42 } // namespace fputil
  43 } // namespace __llvm_libc
  44
  45 #endif // LLVM_LIBC_SRC_SUPPORT_FPUTIL_X86_64_NEAREST_INTEGER_H