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Diffstat (limited to 'src/core/CL/cl_kernels/asymm_helper.h')
-rw-r--r-- | src/core/CL/cl_kernels/asymm_helper.h | 278 |
1 files changed, 0 insertions, 278 deletions
diff --git a/src/core/CL/cl_kernels/asymm_helper.h b/src/core/CL/cl_kernels/asymm_helper.h deleted file mode 100644 index 10169a98ab..0000000000 --- a/src/core/CL/cl_kernels/asymm_helper.h +++ /dev/null @@ -1,278 +0,0 @@ -/* - * Copyright (c) 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. - */ -#ifndef ARM_COMPUTE_ASYMM_HELPER_H -#define ARM_COMPUTE_ASYMM_HELPER_H - -// TODO These functions were implemented to be used in softmax-uint8 kernel and therefore process only vectors of length 16. -// But they can be managed to process arbitrary vector length using VEC_DATA_TYPE(int, size) definition to be more reusable. - -// Algoriths for these functions were taken from -// https://github.com/google/gemmlowp/blob/master/fixedpoint/fixedpoint.h -// and adapted to operate on integer vectors. - -/** For each element of input vector, the corresponding bits of the result item are set - * if the input item is zero. - * - * @param[in] a Input vector whose zero bits define which corresponding bits in result will be set. - * - * @returns Output vector with bits set when corresponding bit in @p a is zero. - */ -inline int16 asymm_mask_if_zero(int16 a) -{ - const int16 all_zeros = 0; - const int16 all_ones = ~0; - return select(all_zeros, all_ones, a == 0); -} - -/** For each element of input vector, the corresponding bits of the result item are set - * if the input item is non-zero. - * - * @param[in] a Input vector whose non-zero bits define which corresponding bits in result will be set. - * - * @returns Output vector with bits set when corresponding bit in @p a is non zero. - */ -inline int16 asymm_mask_if_non_zero(int16 a) -{ - const int16 all_zeros = 0; - const int16 all_ones = ~0; - return select(all_zeros, all_ones, a != 0); -} - -/** Each bit of the result is set to the corresponding bit of either then_val or - * else_val depending on whether the corresponding bit of if_mask is set. - * Equivalent to the VBSL instruction in ARM NEON. - * - * @param[in] if_mask Mask defines will bit be taken from @p then_val or @p else_val depending on corresponding bit in mask is set or not. - * @param[in] then_val Value whose bit will be used for result when corresponding bit in @p if_mask is set. - * @param[in] else_val Value whose bit will be used for result when corresponding bit in @p if_mask is not set. - * - * @returns Result contaning bits from @p then_val or from @p else_val depending on corresponding bit in @p if_mask is set or not. - */ -inline int16 asymm_select_using_mask(int16 if_mask, int16 then_val, int16 else_val) -{ - return (if_mask & then_val) ^ (~if_mask & else_val); -} - -/** Correctly rounded to nearest division by a power of two. - * Also known as a rounding arithmetic right shift. - * - * @param[in] x Value needed to be divided by power of two. - * @param[in] exponent Power of two, must be positive number. - * - * @return Arithmetic right shift. - */ -inline int16 asymm_rounding_divide_by_pow2(int16 x, int exponent) -{ - int16 mask = (1 << exponent) - 1; - const int16 zero = 0; - const int16 one = 1; - int16 threshold = (mask >> 1) + select(zero, one, x < 0); - return (x >> exponent) + select(zero, one, (x & mask) > threshold); -} - -/** Calculates the product of a integer value by a power of two, with either a positive exponent - * (equivalent to an arithmetic left shift, saturating) or a negative exponent - * (equivalent to an arithmetic right shift, rounding to nearest). - * - * @param[in] x Value needed to be multiplied or divided by power of two depending on sign of @p exponent. - * @param[in] exponent Power of two, can be positive or negative number. - * - * @return Arithmetic left or right shift. - */ -inline int16 asymm_saturating_rounding_mult_by_pow2(int16 x, int exponent) -{ - if(exponent < 0) - { - return asymm_rounding_divide_by_pow2(x, -exponent); - } - - const int16 min = INT_MIN; - const int16 max = INT_MAX; - int threshold = ((1 << (31 - exponent)) - 1); - int16 positive_mask = asymm_mask_if_non_zero(x > threshold); - int16 negative_mask = asymm_mask_if_non_zero(x < -threshold); - int16 result = x << exponent; - result = asymm_select_using_mask(positive_mask, max, result); - result = asymm_select_using_mask(negative_mask, min, result); - return result; -} - -/** Calculates (a+b)/2, rounded to the nearest integer. - * Equivalent to VRHADD in the ARM NEON instruction set. - * - * @param[in] a First term of half-sum. - * @param[in] b Second term of half-sum. - * - * @return (a+b)/2, rounded to the nearest integer. - */ -inline int16 asymm_rounding_half_sum(int16 a, int16 b) -{ - long16 a64 = convert_long16(a); - long16 b64 = convert_long16(b); - long16 sum = a64 + b64; - const long16 one = 1; - const long16 minus_one = -1; - long16 sign = select(minus_one, one, sum >= 0); - return convert_int16((sum + sign) / 2); -} - -/** Product of two numbers, interpreting them as fixed-point values in the interval [-1, 1), - * rounding to the nearest value, and saturating -1 * -1 to the maximum value. - * This is equivalent to the VQRDMULH instruction in ARM NEON. - * - * @param[in] a First term of product. - * @param[in] b Second term of product. - * - * @return Product of two numbers. - */ -inline int16 asymm_saturating_rounding_doubling_high_mul(int16 a, int16 b) -{ - int16 overflow = (a == b) && (a == INT_MIN); - long16 a_64 = convert_long16(a); - long16 b_64 = convert_long16(b); - long16 ab_64 = a_64 * b_64; - long16 mask1 = 1 << 30; - long16 mask2 = 1 - (1 << 30); - long16 nudge = select(mask2, mask1, ab_64 >= 0); - long16 mask = 1ll << 31; - int16 ab_x2_high32 = convert_int16((ab_64 + nudge) / mask); - return select(ab_x2_high32, INT_MAX, overflow); -} - -/** Fixed-point multiplication. - * - * @param[in] a Argument 1 in fixed-point format Q(a). - * @param[in] b Argument 2 in fixed-point format Q(b). - * - * @return Result in fixed-point format Q(a+b). - */ -inline int16 asymm_mult(int16 a, int16 b) -{ - return asymm_saturating_rounding_doubling_high_mul(a, b); -} - -/** Calculates \f$ exp(x) \f$ for x in [-1/4, 0). - * - * @param[in] a Argument in fixed-point format Q0. - * - * @return Result in fixed-point format Q0. - */ -inline int16 asymm_exp_on_interval_between_negative_one_quarter_and_0_excl(int16 a) -{ - const int16 constant_term = 1895147668; - const int16 constant_1_over_3 = 715827883; - const int k_fractional_bits = 31; - int16 x = a + (1 << (k_fractional_bits - 3)); - int16 x2 = asymm_mult(x, x); - int16 x3 = asymm_mult(x2, x); - int16 x4 = asymm_mult(x2, x2); - int16 x4_over_4 = asymm_rounding_divide_by_pow2(x4, 2); - int16 x4_over_24_plus_x3_over_6_plus_x2 = asymm_mult((x4_over_4 + x3), constant_1_over_3) + x2; - int16 x4_over_24_plus_x3_over_6_plus_x2_over_2 = asymm_rounding_divide_by_pow2(x4_over_24_plus_x3_over_6_plus_x2, 1); - return constant_term + asymm_mult(constant_term, x + x4_over_24_plus_x3_over_6_plus_x2_over_2); -} - -/** Calculates \f$ exp(x) \f$ for x < 0. - * - * @param[in] a Argument in fixed-point format Q(k_integer_bits). - * @param[in] k_integer_bits Number of integer bit in argument. - * - * @return Result in fixed-point format Q0. - */ -inline int16 asymm_exp_on_negative_values(int16 a, int k_integer_bits) -{ - const int k_fractional_bits = 31 - k_integer_bits; - int16 k_one_quarter = 1 << (k_fractional_bits - 2); - int16 mask = k_one_quarter - 1; - int16 a_mod_quarter_minus_one_quarter = (a & mask) - k_one_quarter; - int16 a_mod_quarter_minus_one_quarter_scaled = a_mod_quarter_minus_one_quarter << k_integer_bits; - int16 result = asymm_exp_on_interval_between_negative_one_quarter_and_0_excl(a_mod_quarter_minus_one_quarter_scaled); - int16 remainder = a_mod_quarter_minus_one_quarter - a; - -#define EXP_BARREL_SHIFTER(Exponent, FixedPointMultiplier) \ - if(k_integer_bits > Exponent) \ - { \ - const int k_shift_amount = k_integer_bits > Exponent ? k_fractional_bits + Exponent : 0; \ - result = asymm_select_using_mask( \ - asymm_mask_if_non_zero(remainder & (1 << k_shift_amount)), \ - asymm_mult(result, FixedPointMultiplier), result); \ - } - EXP_BARREL_SHIFTER(-2, 1672461947); - EXP_BARREL_SHIFTER(-1, 1302514674); - EXP_BARREL_SHIFTER(+0, 790015084); - EXP_BARREL_SHIFTER(+1, 290630308); - EXP_BARREL_SHIFTER(+2, 39332535); - EXP_BARREL_SHIFTER(+3, 720401); - EXP_BARREL_SHIFTER(+4, 242); -#undef EXP_BARREL_SHIFTER - - if(k_integer_bits > 5) - { - const int16 clamp = -(1 << (k_fractional_bits + 5)); - result = asymm_select_using_mask(asymm_mask_if_non_zero(a < clamp), 0, result); - } - - const int16 Q0_one = INT_MAX; - return asymm_select_using_mask(asymm_mask_if_zero(a), Q0_one, result); -} - -/** Calculates \f$ 1 / (1 + x) \f$ for x in (0, 1). - * - * @param[in] a Argument in fixed-point format Q0. - * - * @return Result in fixed-point format Q0. - */ -inline int16 asymm_one_over_one_plus_x_for_x_in_0_1(int16 a) -{ - const int16 Q0_one = INT_MAX; - const int16 Q2_one = 1 << (31 - 2); - int16 half_denominator = asymm_rounding_half_sum(a, Q0_one); - const int16 Q2_48_over_17 = 1515870810; - const int16 Q2_neg_32_over_17 = -1010580540; - int16 x = Q2_48_over_17 + asymm_mult(half_denominator, Q2_neg_32_over_17); - for(int i = 0; i < 3; i++) - { - int16 half_denominator_times_x = asymm_mult(half_denominator, x); - int16 one_minus_half_denominator_times_x = Q2_one - half_denominator_times_x; - int16 tmp = asymm_mult(x, one_minus_half_denominator_times_x); - x = x + asymm_saturating_rounding_mult_by_pow2(tmp, 2); - } - return asymm_saturating_rounding_mult_by_pow2(x, 1); -} - -/** Considering the integer value as fixed-point, change the number of integer bits and update value accordingly. - * - * @param[in] value Value to be rescaled. - * @param[in] src_integer_bits Old number of integer bits. - * @param[in] dst_integer_bits New number of integer bits. - * - * @return Rescaled value. - */ -inline int16 asymm_rescale(int16 value, int src_integer_bits, int dst_integer_bits) -{ - int exponent = src_integer_bits - dst_integer_bits; - return asymm_saturating_rounding_mult_by_pow2(value, exponent); -} - -#endif // ARM_COMPUTE_ASYMM_HELPER_H |