diff options
Diffstat (limited to 'libc/src/math/generic/exp2m1f16.cpp')
| -rw-r--r-- | libc/src/math/generic/exp2m1f16.cpp | 155 |
1 files changed, 2 insertions, 153 deletions
diff --git a/libc/src/math/generic/exp2m1f16.cpp b/libc/src/math/generic/exp2m1f16.cpp index ce0cc60..497a288 100644 --- a/libc/src/math/generic/exp2m1f16.cpp +++ b/libc/src/math/generic/exp2m1f16.cpp @@ -7,163 +7,12 @@ //===----------------------------------------------------------------------===// #include "src/math/exp2m1f16.h" -#include "hdr/errno_macros.h" -#include "hdr/fenv_macros.h" -#include "src/__support/FPUtil/FEnvImpl.h" -#include "src/__support/FPUtil/FPBits.h" -#include "src/__support/FPUtil/PolyEval.h" -#include "src/__support/FPUtil/cast.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" -#include "src/__support/macros/properties/cpu_features.h" -#include "src/__support/math/expxf16_utils.h" +#include "src/__support/math/exp2m1f16.h" namespace LIBC_NAMESPACE_DECL { -#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS -static constexpr fputil::ExceptValues<float16, 6> EXP2M1F16_EXCEPTS_LO = {{ - // (input, RZ output, RU offset, RD offset, RN offset) - // x = 0x1.cf4p-13, exp2m1f16(x) = 0x1.41p-13 (RZ) - {0x0b3dU, 0x0904U, 1U, 0U, 1U}, - // x = 0x1.4fcp-12, exp2m1f16(x) = 0x1.d14p-13 (RZ) - {0x0d3fU, 0x0b45U, 1U, 0U, 1U}, - // x = 0x1.63p-11, exp2m1f16(x) = 0x1.ec4p-12 (RZ) - {0x118cU, 0x0fb1U, 1U, 0U, 0U}, - // x = 0x1.6fp-7, exp2m1f16(x) = 0x1.fe8p-8 (RZ) - {0x21bcU, 0x1ffaU, 1U, 0U, 1U}, - // x = -0x1.c6p-10, exp2m1f16(x) = -0x1.3a8p-10 (RZ) - {0x9718U, 0x94eaU, 0U, 1U, 0U}, - // x = -0x1.cfcp-10, exp2m1f16(x) = -0x1.414p-10 (RZ) - {0x973fU, 0x9505U, 0U, 1U, 0U}, -}}; - -#ifdef LIBC_TARGET_CPU_HAS_FMA_FLOAT -static constexpr size_t N_EXP2M1F16_EXCEPTS_HI = 6; -#else -static constexpr size_t N_EXP2M1F16_EXCEPTS_HI = 7; -#endif - -static constexpr fputil::ExceptValues<float16, N_EXP2M1F16_EXCEPTS_HI> - EXP2M1F16_EXCEPTS_HI = {{ - // (input, RZ output, RU offset, RD offset, RN offset) - // x = 0x1.e58p-3, exp2m1f16(x) = 0x1.6dcp-3 (RZ) - {0x3396U, 0x31b7U, 1U, 0U, 0U}, -#ifndef LIBC_TARGET_CPU_HAS_FMA_FLOAT - // x = 0x1.2e8p-2, exp2m1f16(x) = 0x1.d14p-3 (RZ) - {0x34baU, 0x3345U, 1U, 0U, 0U}, -#endif - // x = 0x1.ad8p-2, exp2m1f16(x) = 0x1.598p-2 (RZ) - {0x36b6U, 0x3566U, 1U, 0U, 0U}, -#ifdef LIBC_TARGET_CPU_HAS_FMA_FLOAT - // x = 0x1.edcp-2, exp2m1f16(x) = 0x1.964p-2 (RZ) - {0x37b7U, 0x3659U, 1U, 0U, 1U}, -#endif - // x = -0x1.804p-3, exp2m1f16(x) = -0x1.f34p-4 (RZ) - {0xb201U, 0xafcdU, 0U, 1U, 1U}, - // x = -0x1.f3p-3, exp2m1f16(x) = -0x1.3e4p-3 (RZ) - {0xb3ccU, 0xb0f9U, 0U, 1U, 0U}, - // x = -0x1.294p-1, exp2m1f16(x) = -0x1.53p-2 (RZ) - {0xb8a5U, 0xb54cU, 0U, 1U, 1U}, -#ifndef LIBC_TARGET_CPU_HAS_FMA_FLOAT - // x = -0x1.a34p-1, exp2m1f16(x) = -0x1.bb4p-2 (RZ) - {0xba8dU, 0xb6edU, 0U, 1U, 1U}, -#endif - }}; -#endif // !LIBC_MATH_HAS_SKIP_ACCURATE_PASS - LLVM_LIBC_FUNCTION(float16, exp2m1f16, (float16 x)) { - using namespace math::expxf16_internal; - using FPBits = fputil::FPBits<float16>; - FPBits x_bits(x); - - uint16_t x_u = x_bits.uintval(); - uint16_t x_abs = x_u & 0x7fffU; - - // When |x| <= 2^(-3), or |x| >= 11, or x is NaN. - if (LIBC_UNLIKELY(x_abs <= 0x3000U || x_abs >= 0x4980U)) { - // exp2m1(NaN) = NaN - if (x_bits.is_nan()) { - if (x_bits.is_signaling_nan()) { - fputil::raise_except_if_required(FE_INVALID); - return FPBits::quiet_nan().get_val(); - } - - return x; - } - - // When x >= 16. - if (x_u >= 0x4c00 && x_bits.is_pos()) { - // exp2m1(+inf) = +inf - if (x_bits.is_inf()) - return FPBits::inf().get_val(); - - switch (fputil::quick_get_round()) { - case FE_TONEAREST: - case FE_UPWARD: - fputil::set_errno_if_required(ERANGE); - fputil::raise_except_if_required(FE_OVERFLOW | FE_INEXACT); - return FPBits::inf().get_val(); - default: - return FPBits::max_normal().get_val(); - } - } - - // When x < -11. - if (x_u > 0xc980U) { - // exp2m1(-inf) = -1 - if (x_bits.is_inf()) - return FPBits::one(Sign::NEG).get_val(); - - // When -12 < x < -11, round(2^x - 1, HP, RN) = -0x1.ffcp-1. - if (x_u < 0xca00U) - return fputil::round_result_slightly_down( - fputil::cast<float16>(-0x1.ffcp-1)); - - // When x <= -12, round(2^x - 1, HP, RN) = -1. - switch (fputil::quick_get_round()) { - case FE_TONEAREST: - case FE_DOWNWARD: - return FPBits::one(Sign::NEG).get_val(); - default: - return fputil::cast<float16>(-0x1.ffcp-1); - } - } - - // When |x| <= 2^(-3). - if (x_abs <= 0x3000U) { -#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS - if (auto r = EXP2M1F16_EXCEPTS_LO.lookup(x_u); - LIBC_UNLIKELY(r.has_value())) - return r.value(); -#endif // !LIBC_MATH_HAS_SKIP_ACCURATE_PASS - - float xf = x; - // Degree-5 minimax polynomial generated by Sollya with the following - // commands: - // > display = hexadecimal; - // > P = fpminimax((2^x - 1)/x, 4, [|SG...|], [-2^-3, 2^-3]); - // > x * P; - return fputil::cast<float16>( - xf * fputil::polyeval(xf, 0x1.62e43p-1f, 0x1.ebfbdep-3f, - 0x1.c6af88p-5f, 0x1.3b45d6p-7f, - 0x1.641e7cp-10f)); - } - } - -#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS - if (auto r = EXP2M1F16_EXCEPTS_HI.lookup(x_u); LIBC_UNLIKELY(r.has_value())) - return r.value(); -#endif // !LIBC_MATH_HAS_SKIP_ACCURATE_PASS - - // exp2(x) = exp2(hi + mid) * exp2(lo) - auto [exp2_hi_mid, exp2_lo] = exp2_range_reduction(x); - // exp2m1(x) = exp2(hi + mid) * exp2(lo) - 1 - return fputil::cast<float16>( - fputil::multiply_add(exp2_hi_mid, exp2_lo, -1.0f)); + return math::exp2m1f16(x); } } // namespace LIBC_NAMESPACE_DECL |