1 // This file is part of Eigen, a lightweight C++ template library 2 // for linear algebra. 3 // 4 // This Source Code Form is subject to the terms of the Mozilla 5 // Public License v. 2.0. If a copy of the MPL was not distributed 6 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/. 7 8 /* The sin, cos, exp, and log functions of this file come from 9 * Julien Pommier's sse math library: http://gruntthepeon.free.fr/ssemath/ 10 */ 11 12 #ifndef EIGEN_MATH_FUNCTIONS_NEON_H 13 #define EIGEN_MATH_FUNCTIONS_NEON_H 14 15 namespace Eigen { 16 17 namespace internal { 18 19 template<> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED 20 Packet4f pexp<Packet4f>(const Packet4f& _x) 21 { 22 Packet4f x = _x; 23 Packet4f tmp, fx; 24 25 _EIGEN_DECLARE_CONST_Packet4f(1 , 1.0f); 26 _EIGEN_DECLARE_CONST_Packet4f(half, 0.5f); 27 _EIGEN_DECLARE_CONST_Packet4i(0x7f, 0x7f); 28 _EIGEN_DECLARE_CONST_Packet4f(exp_hi, 88.3762626647950f); 29 _EIGEN_DECLARE_CONST_Packet4f(exp_lo, -88.3762626647949f); 30 _EIGEN_DECLARE_CONST_Packet4f(cephes_LOG2EF, 1.44269504088896341f); 31 _EIGEN_DECLARE_CONST_Packet4f(cephes_exp_C1, 0.693359375f); 32 _EIGEN_DECLARE_CONST_Packet4f(cephes_exp_C2, -2.12194440e-4f); 33 _EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p0, 1.9875691500E-4f); 34 _EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p1, 1.3981999507E-3f); 35 _EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p2, 8.3334519073E-3f); 36 _EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p3, 4.1665795894E-2f); 37 _EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p4, 1.6666665459E-1f); 38 _EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p5, 5.0000001201E-1f); 39 40 x = vminq_f32(x, p4f_exp_hi); 41 x = vmaxq_f32(x, p4f_exp_lo); 42 43 /* express exp(x) as exp(g + n*log(2)) */ 44 fx = vmlaq_f32(p4f_half, x, p4f_cephes_LOG2EF); 45 46 /* perform a floorf */ 47 tmp = vcvtq_f32_s32(vcvtq_s32_f32(fx)); 48 49 /* if greater, substract 1 */ 50 Packet4ui mask = vcgtq_f32(tmp, fx); 51 mask = vandq_u32(mask, vreinterpretq_u32_f32(p4f_1)); 52 53 fx = vsubq_f32(tmp, vreinterpretq_f32_u32(mask)); 54 55 tmp = vmulq_f32(fx, p4f_cephes_exp_C1); 56 Packet4f z = vmulq_f32(fx, p4f_cephes_exp_C2); 57 x = vsubq_f32(x, tmp); 58 x = vsubq_f32(x, z); 59 60 Packet4f y = vmulq_f32(p4f_cephes_exp_p0, x); 61 z = vmulq_f32(x, x); 62 y = vaddq_f32(y, p4f_cephes_exp_p1); 63 y = vmulq_f32(y, x); 64 y = vaddq_f32(y, p4f_cephes_exp_p2); 65 y = vmulq_f32(y, x); 66 y = vaddq_f32(y, p4f_cephes_exp_p3); 67 y = vmulq_f32(y, x); 68 y = vaddq_f32(y, p4f_cephes_exp_p4); 69 y = vmulq_f32(y, x); 70 y = vaddq_f32(y, p4f_cephes_exp_p5); 71 72 y = vmulq_f32(y, z); 73 y = vaddq_f32(y, x); 74 y = vaddq_f32(y, p4f_1); 75 76 /* build 2^n */ 77 int32x4_t mm; 78 mm = vcvtq_s32_f32(fx); 79 mm = vaddq_s32(mm, p4i_0x7f); 80 mm = vshlq_n_s32(mm, 23); 81 Packet4f pow2n = vreinterpretq_f32_s32(mm); 82 83 y = vmulq_f32(y, pow2n); 84 return y; 85 } 86 87 } // end namespace internal 88 89 } // end namespace Eigen 90 91 #endif // EIGEN_MATH_FUNCTIONS_NEON_H 92
