tan.cpp | Explore in Territory

//===-- Double-precision tan 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/tan.h"
#include "hdr/errno_macros.h"
#include "src/__support/FPUtil/FEnvImpl.h"
#include "src/__support/FPUtil/FPBits.h"
#include "src/__support/FPUtil/PolyEval.h"
#include "src/__support/FPUtil/double_double.h"
#include "src/__support/FPUtil/dyadic_float.h"
#include "src/__support/FPUtil/except_value_utils.h"
#include "src/__support/FPUtil/multiply_add.h"
#include "src/__support/FPUtil/rounding_mode.h"
#include "src/__support/common.h"
#include "src/__support/macros/config.h"
#include "src/__support/macros/optimization.h"            // LIBC_UNLIKELY
#include "src/__support/macros/properties/cpu_features.h" // LIBC_TARGET_CPU_HAS_FMA

// TODO: We might be able to improve the performance of large range reduction of
// non-FMA targets further by operating directly on 25-bit chunks of 128/pi and
// pre-split SIN_K_PI_OVER_128, but that might double the memory footprint of
// those lookup table.
#include "range_reduction_double_common.h"

#if ((LIBC_MATH & LIBC_MATH_SKIP_ACCURATE_PASS) != 0)
#define LIBC_MATH_TAN_SKIP_ACCURATE_PASS
#endif

namespace LIBC_NAMESPACE_DECL {

DoubleDouble;
Float128;

namespace {

LIBC_INLINE DoubleDouble tan_eval(const DoubleDouble &u) { … }

// Accurate evaluation of tan for small u.
[[maybe_unused]] Float128 tan_eval(const Float128 &u) { … }

// Calculation a / b = a * (1/b) for Float128.
// Using the initial approximation of q ~ (1/b), then apply 2 Newton-Raphson
// iterations, before multiplying by a.
[[maybe_unused]] Float128 newton_raphson_div(const Float128 &a, Float128 b,
                                             double q) { … }

} // anonymous namespace

LLVM_LIBC_FUNCTION(double, tan, (double x)) { … }

} // namespace LIBC_NAMESPACE_DECL
llvm/libc/src/math/generic/tan.cpp
