diff options
| -rw-r--r-- | libc/docs/math.rst | 2 | ||||
| -rw-r--r-- | libc/src/math/generic/CMakeLists.txt | 2 | ||||
| -rw-r--r-- | libc/src/math/generic/expf.cpp | 12 |
3 files changed, 8 insertions, 8 deletions
diff --git a/libc/docs/math.rst b/libc/docs/math.rst index 6480a98..42d0961 100644 --- a/libc/docs/math.rst +++ b/libc/docs/math.rst @@ -199,7 +199,7 @@ Performance +==============+===========+===================+===========+===================+=====================================+============+=========================+==============+===============+ | cosf | 37 | 32 | 73 | 72 | :math:`[0, 2\pi]` | Ryzen 1700 | Ubuntu 20.04 LTS x86_64 | Clang 12.0.0 | | +--------------+-----------+-------------------+-----------+-------------------+-------------------------------------+------------+-------------------------+--------------+---------------+ -| expf | 14 | 9 | 58 | 42 | :math:`[-10, 10]` | Ryzen 1700 | Ubuntu 20.04 LTS x86_64 | Clang 12.0.0 | FMA | +| expf | 9 | 7 | 44 | 38 | :math:`[-10, 10]` | Ryzen 1700 | Ubuntu 20.04 LTS x86_64 | Clang 12.0.0 | FMA | +--------------+-----------+-------------------+-----------+-------------------+-------------------------------------+------------+-------------------------+--------------+---------------+ | exp2f | 25 | 8 | 81 | 37 | :math:`[-10, 10]` | Ryzen 1700 | Ubuntu 20.04 LTS x86_64 | Clang 12.0.0 | FMA | +--------------+-----------+-------------------+-----------+-------------------+-------------------------------------+------------+-------------------------+--------------+---------------+ diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt index 7b6a378..2658b96 100644 --- a/libc/src/math/generic/CMakeLists.txt +++ b/libc/src/math/generic/CMakeLists.txt @@ -483,6 +483,8 @@ add_entrypoint_object( DEPENDS .common_constants libc.src.__support.FPUtil.fputil + libc.src.__support.FPUtil.multiply_add + libc.src.__support.FPUtil.nearest_integer libc.src.__support.FPUtil.polyeval libc.include.math COMPILE_OPTIONS diff --git a/libc/src/math/generic/expf.cpp b/libc/src/math/generic/expf.cpp index 948b101..1003699 100644 --- a/libc/src/math/generic/expf.cpp +++ b/libc/src/math/generic/expf.cpp @@ -10,9 +10,10 @@ #include "common_constants.h" // Lookup tables EXP_M1 and EXP_M2. #include "src/__support/FPUtil/BasicOperations.h" #include "src/__support/FPUtil/FEnvImpl.h" -#include "src/__support/FPUtil/FMA.h" #include "src/__support/FPUtil/FPBits.h" #include "src/__support/FPUtil/PolyEval.h" +#include "src/__support/FPUtil/multiply_add.h" +#include "src/__support/FPUtil/nearest_integer.h" #include "src/__support/common.h" #include <errno.h> @@ -80,13 +81,10 @@ LLVM_LIBC_FUNCTION(float, expf, (float x)) { // generated by Sollya. // x_hi = (hi + mid) * 2^7 = round(x * 2^7). - // The default rounding mode for float-to-int conversion in C++ is - // round-toward-zero. To make it round-to-nearest, we add (-1)^sign(x) * 0.5 - // before conversion. - int x_hi = static_cast<int>(x * 0x1.0p7f + (xbits.get_sign() ? -0.5f : 0.5f)); + float kf = fputil::nearest_integer(x * 0x1.0p7f); // Subtract (hi + mid) from x to get lo. - x -= static_cast<float>(x_hi) * 0x1.0p-7f; - double xd = static_cast<double>(x); + double xd = static_cast<double>(fputil::multiply_add(kf, -0x1.0p-7f, x)); + int x_hi = static_cast<int>(kf); x_hi += 104 << 7; // hi = x_hi >> 7 double exp_hi = EXP_M1[x_hi >> 7]; |