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92 lines
2.8 KiB
C++
92 lines
2.8 KiB
C++
// This file is part of Eigen, a lightweight C++ template library
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// for linear algebra.
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//
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// This Source Code Form is subject to the terms of the Mozilla
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// Public License v. 2.0. If a copy of the MPL was not distributed
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// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
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/* The sin, cos, exp, and log functions of this file come from
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* Julien Pommier's sse math library: http://gruntthepeon.free.fr/ssemath/
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*/
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#ifndef EIGEN_MATH_FUNCTIONS_NEON_H
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#define EIGEN_MATH_FUNCTIONS_NEON_H
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namespace Eigen {
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namespace internal {
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template<> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED
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Packet4f pexp<Packet4f>(const Packet4f& _x)
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{
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Packet4f x = _x;
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Packet4f tmp, fx;
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_EIGEN_DECLARE_CONST_Packet4f(1 , 1.0f);
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_EIGEN_DECLARE_CONST_Packet4f(half, 0.5f);
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_EIGEN_DECLARE_CONST_Packet4i(0x7f, 0x7f);
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_EIGEN_DECLARE_CONST_Packet4f(exp_hi, 88.3762626647950f);
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_EIGEN_DECLARE_CONST_Packet4f(exp_lo, -88.3762626647949f);
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_EIGEN_DECLARE_CONST_Packet4f(cephes_LOG2EF, 1.44269504088896341f);
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_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_C1, 0.693359375f);
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_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_C2, -2.12194440e-4f);
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_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p0, 1.9875691500E-4f);
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_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p1, 1.3981999507E-3f);
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_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p2, 8.3334519073E-3f);
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_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p3, 4.1665795894E-2f);
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_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p4, 1.6666665459E-1f);
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_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p5, 5.0000001201E-1f);
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x = vminq_f32(x, p4f_exp_hi);
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x = vmaxq_f32(x, p4f_exp_lo);
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/* express exp(x) as exp(g + n*log(2)) */
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fx = vmlaq_f32(p4f_half, x, p4f_cephes_LOG2EF);
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/* perform a floorf */
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tmp = vcvtq_f32_s32(vcvtq_s32_f32(fx));
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/* if greater, substract 1 */
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Packet4ui mask = vcgtq_f32(tmp, fx);
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mask = vandq_u32(mask, vreinterpretq_u32_f32(p4f_1));
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fx = vsubq_f32(tmp, vreinterpretq_f32_u32(mask));
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tmp = vmulq_f32(fx, p4f_cephes_exp_C1);
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Packet4f z = vmulq_f32(fx, p4f_cephes_exp_C2);
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x = vsubq_f32(x, tmp);
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x = vsubq_f32(x, z);
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Packet4f y = vmulq_f32(p4f_cephes_exp_p0, x);
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z = vmulq_f32(x, x);
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y = vaddq_f32(y, p4f_cephes_exp_p1);
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y = vmulq_f32(y, x);
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y = vaddq_f32(y, p4f_cephes_exp_p2);
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y = vmulq_f32(y, x);
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y = vaddq_f32(y, p4f_cephes_exp_p3);
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y = vmulq_f32(y, x);
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y = vaddq_f32(y, p4f_cephes_exp_p4);
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y = vmulq_f32(y, x);
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y = vaddq_f32(y, p4f_cephes_exp_p5);
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y = vmulq_f32(y, z);
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y = vaddq_f32(y, x);
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y = vaddq_f32(y, p4f_1);
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/* build 2^n */
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int32x4_t mm;
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mm = vcvtq_s32_f32(fx);
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mm = vaddq_s32(mm, p4i_0x7f);
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mm = vshlq_n_s32(mm, 23);
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Packet4f pow2n = vreinterpretq_f32_s32(mm);
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y = vmulq_f32(y, pow2n);
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return y;
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}
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} // end namespace internal
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} // end namespace Eigen
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#endif // EIGEN_MATH_FUNCTIONS_NEON_H
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