diff options
Diffstat (limited to 'arm_compute/core/NEON/NEMath.inl')
| -rw-r--r-- | arm_compute/core/NEON/NEMath.inl | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/arm_compute/core/NEON/NEMath.inl b/arm_compute/core/NEON/NEMath.inl new file mode 100644 index 0000000000..a31a4c0dc5 --- /dev/null +++ b/arm_compute/core/NEON/NEMath.inl @@ -0,0 +1,141 @@ +/* + * Copyright (c) 2016, 2017 ARM Limited. + * + * SPDX-License-Identifier: MIT + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to + * deal in the Software without restriction, including without limitation the + * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or + * sell copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in all + * copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +namespace arm_compute +{ +/* Exponent polynomial coefficients */ +const std::array<float32x4_t, 8> exp_tab = +{ + { + vdupq_n_f32(1.f), + vdupq_n_f32(0.0416598916054f), + vdupq_n_f32(0.500000596046f), + vdupq_n_f32(0.0014122662833f), + vdupq_n_f32(1.00000011921f), + vdupq_n_f32(0.00833693705499f), + vdupq_n_f32(0.166665703058f), + vdupq_n_f32(0.000195780929062f), + } +}; + +/* Logarithm polynomial coefficients */ +const std::array<float32x4_t, 8> log_tab = +{ + { + vdupq_n_f32(-2.29561495781f), + vdupq_n_f32(-2.47071170807f), + vdupq_n_f32(-5.68692588806f), + vdupq_n_f32(-0.165253549814f), + vdupq_n_f32(5.17591238022f), + vdupq_n_f32(0.844007015228f), + vdupq_n_f32(4.58445882797f), + vdupq_n_f32(0.0141278216615f), + } +}; + +inline float32x4_t vinvsqrtq_f32(float32x4_t x) +{ + float32x4_t sqrt_reciprocal = vrsqrteq_f32(x); + sqrt_reciprocal = vmulq_f32(vrsqrtsq_f32(vmulq_f32(x, sqrt_reciprocal), sqrt_reciprocal), sqrt_reciprocal); + sqrt_reciprocal = vmulq_f32(vrsqrtsq_f32(vmulq_f32(x, sqrt_reciprocal), sqrt_reciprocal), sqrt_reciprocal); + + return sqrt_reciprocal; +} + +inline float32x4_t vinvq_f32(float32x4_t x) +{ + float32x4_t recip = vrecpeq_f32(x); + recip = vmulq_f32(vrecpsq_f32(x, recip), recip); + recip = vmulq_f32(vrecpsq_f32(x, recip), recip); + return recip; +} + +inline float32x4_t vtaylor_polyq_f32(float32x4_t x, const std::array<float32x4_t, 8> &coeffs) +{ + float32x4_t A = vmlaq_f32(coeffs[0], coeffs[4], x); + float32x4_t B = vmlaq_f32(coeffs[2], coeffs[6], x); + float32x4_t C = vmlaq_f32(coeffs[1], coeffs[5], x); + float32x4_t D = vmlaq_f32(coeffs[3], coeffs[7], x); + float32x4_t x2 = vmulq_f32(x, x); + float32x4_t x4 = vmulq_f32(x2, x2); + float32x4_t res = vmlaq_f32(vmlaq_f32(A, B, x2), vmlaq_f32(C, D, x2), x4); + return res; +} + +inline float32x4_t vexpq_f32(float32x4_t x) +{ + static const float32x4_t CONST_LN2 = vdupq_n_f32(0.6931471805f); // ln(2) + static const float32x4_t CONST_INV_LN2 = vdupq_n_f32(1.4426950408f); // 1/ln(2) + + // Perform range reduction [-log(2),log(2)] + int32x4_t m = vcvtq_s32_f32(vmulq_f32(x, CONST_INV_LN2)); + float32x4_t val = vmlsq_f32(x, vcvtq_f32_s32(m), CONST_LN2); + + // Polynomial Approximation + float32x4_t poly = vtaylor_polyq_f32(val, exp_tab); + + // Reconstruct + poly = vreinterpretq_f32_s32(vaddq_s32(vreinterpretq_s32_f32(poly), vshlq_n_s32(m, 23))); + + return poly; +} + +inline float32x4_t vlogq_f32(float32x4_t x) +{ + static const int32x4_t CONST_127 = vdupq_n_s32(127); // 127 + static const float32x4_t CONST_LN2 = vdupq_n_f32(0.6931471805f); // ln(2) + + // Extract exponent + int32x4_t m = vsubq_s32(vreinterpretq_s32_u32(vshrq_n_u32(vreinterpretq_u32_f32(x), 23)), CONST_127); + float32x4_t val = vreinterpretq_f32_s32(vsubq_s32(vreinterpretq_s32_f32(x), vshlq_n_s32(m, 23))); + + // Polynomial Approximation + float32x4_t poly = vtaylor_polyq_f32(val, log_tab); + + // Reconstruct + poly = vmlaq_f32(poly, vcvtq_f32_s32(m), CONST_LN2); + + return poly; +} + +inline float32x4_t vtanhq_f32(float32x4_t val) +{ + static const float32x4_t CONST_1 = vdupq_n_f32(1.f); + static const float32x4_t CONST_2 = vdupq_n_f32(2.f); + static const float32x4_t CONST_MIN_TANH = vdupq_n_f32(-10.f); + static const float32x4_t CONST_MAX_TANH = vdupq_n_f32(10.f); + + float32x4_t x = vminq_f32(vmaxq_f32(val, CONST_MIN_TANH), CONST_MAX_TANH); + float32x4_t exp2x = vexpq_f32(vmulq_f32(CONST_2, x)); + float32x4_t num = vsubq_f32(exp2x, CONST_1); + float32x4_t den = vaddq_f32(exp2x, CONST_1); + float32x4_t tanh = vmulq_f32(num, vinvq_f32(den)); + return tanh; +} + +inline float32x4_t vpowq_f32(float32x4_t val, float32x4_t n) +{ + return vexpq_f32(vmulq_f32(n, vlogq_f32(val))); +} +}
\ No newline at end of file |