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diff --git a/compute/cker/include/cker/gemmlowp/FixedPoint.h b/compute/cker/include/cker/gemmlowp/FixedPoint.h
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+/*
+ * Copyright (c) 2019 Samsung Electronics Co., Ltd. All Rights Reserved
+ * Copyright 2015 The Gemmlowp Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __NNFW_CKER_GEMMLOWP_FIXED_POINT_H__
+#define __NNFW_CKER_GEMMLOWP_FIXED_POINT_H__
+
+#include <algorithm>
+#include <cassert>
+
+namespace nnfw
+{
+namespace cker
+{
+namespace gemmlowp
+{
+
+inline int32_t RoundingHalfSum(int32_t a, int32_t b)
+{
+ int64_t a64 = a;
+ int64_t b64 = b;
+ int64_t sum = a64 + b64;
+ int64_t sign = sum >= 0 ? 1 : -1;
+ return static_cast<int32_t>((sum + sign) / 2);
+}
+
+inline int32_t SaturatingRoundingDoublingHighMul(int32_t a, int32_t b)
+{
+ bool overflow = a == b && a == std::numeric_limits<int32_t>::min();
+ int64_t a_64(a);
+ int64_t b_64(b);
+ int64_t ab_64 = a_64 * b_64;
+ int32_t nudge = ab_64 >= 0 ? (1 << 30) : (1 - (1 << 30));
+ int32_t ab_x2_high32 = static_cast<int32_t>((ab_64 + nudge) / (1ll << 31));
+ return overflow ? std::numeric_limits<int32_t>::max() : ab_x2_high32;
+}
+
+// Correctly-rounded-to-nearest division by a power-of-two.
+// Also known as a rounding arithmetic right shift.
+inline int32_t RoundingDivideByPOT(int32_t x, int exponent)
+{
+ assert(exponent >= 0);
+ assert(exponent <= 31);
+ const int32_t mask = ((1ll << exponent) - 1);
+ const int32_t zero = 0;
+ const int32_t one = 1;
+ const int32_t remainder = x & mask;
+ const int32_t threshold = (mask >> 1) + ((x < zero) ? one : zero);
+ return ((x >> exponent) + ((remainder > threshold) ? one : zero));
+}
+
+// Returns the product of a run-time integer value by a compile-time 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).
+template <int Exponent, int ExponentSign = (Exponent > 0 ? 1 : Exponent < 0 ? -1 : 0)>
+struct ImplSaturatingRoundingMultiplyByPOT
+{
+};
+
+template <int Exponent> struct ImplSaturatingRoundingMultiplyByPOT<Exponent, 0>
+{
+ static int32_t eval(int32_t x) { return x; }
+};
+
+template <int Exponent> struct ImplSaturatingRoundingMultiplyByPOT<Exponent, 1>
+{
+ static int32_t eval(int32_t x)
+ {
+ const int32_t min = (std::numeric_limits<int32_t>::min());
+ const int32_t max = (std::numeric_limits<int32_t>::max());
+ const int32_t threshold = ((1 << (31 - Exponent)) - 1);
+ const int32_t zero = 0;
+ const int32_t one = 1;
+
+ const int32_t positive_mask = ((x > threshold) ? ~zero : zero);
+ const int32_t negative_mask = ((x < -threshold) ? ~zero : zero);
+
+ int32_t result = (x * (one << Exponent));
+ result = (positive_mask ? max : result);
+ result = (negative_mask ? min : result);
+ return result;
+ }
+};
+
+template <int Exponent> struct ImplSaturatingRoundingMultiplyByPOT<Exponent, -1>
+{
+ static int32_t eval(int32_t x) { return RoundingDivideByPOT(x, -Exponent); }
+};
+
+template <int Exponent> int32_t SaturatingRoundingMultiplyByPOT(int32_t x)
+{
+ return ImplSaturatingRoundingMultiplyByPOT<Exponent>::eval(x);
+}
+
+template <int tIntegerBits> class FixedPoint
+{
+public:
+ static constexpr int kTotalBits = 8 * sizeof(int32_t);
+ static constexpr int kIntegerBits = tIntegerBits;
+ static constexpr int kFractionalBits = kTotalBits - 1 - kIntegerBits;
+ static_assert(kIntegerBits >= 0 && kIntegerBits < kTotalBits, "bad IntegerBits");
+
+ static int32_t ScalarRawMax() { return std::numeric_limits<int32_t>::max(); }
+
+ static FixedPoint FromRaw(int32_t x)
+ {
+ FixedPoint retval;
+ retval.raw() = x;
+ return retval;
+ }
+
+ static FixedPoint FromScalarRaw(int32_t x) { return FromRaw(x); }
+
+ template <int Exponent> static FixedPoint ConstantPOT()
+ {
+ static constexpr int kOffset = kFractionalBits + Exponent;
+ static_assert(kOffset < 31, "Constant not exactly representable in this fixed-point format");
+ return FromScalarRaw((int32_t)1 << kOffset);
+ }
+
+ static FixedPoint Zero() { return FromScalarRaw(0); }
+
+ static FixedPoint One()
+ {
+ return FromScalarRaw(kIntegerBits == 0 ? ScalarRawMax() : ((int32_t)1 << kFractionalBits));
+ }
+
+ int32_t raw() const { return i_; }
+ int32_t &raw() { return i_; }
+
+private:
+ int32_t i_;
+};
+
+// A FixedPoint multiplication is just a
+// SaturatingRoundingDoublingHighMul operation on the underlying
+// raw integer values. The IntegerBits simply add up, as is obvious
+// from the fact that the range is [-2^IntegerBits, 2^IntegerBits).
+template <int tIntegerBits_a, int tIntegerBits_b>
+FixedPoint<tIntegerBits_a + tIntegerBits_b> operator*(FixedPoint<tIntegerBits_a> a,
+ FixedPoint<tIntegerBits_b> b)
+{
+ FixedPoint<tIntegerBits_a + tIntegerBits_b> c;
+ c.raw() = SaturatingRoundingDoublingHighMul(a.raw(), b.raw());
+ return c;
+}
+
+// Tweaking IntegerBits gives exact multiplication by a power of two.
+template <int tExponent, int tIntegerBits>
+FixedPoint<tExponent + tIntegerBits> ExactMulByPot(FixedPoint<tIntegerBits> a)
+{
+ FixedPoint<tExponent + tIntegerBits> c;
+ c.raw() = a.raw();
+ return c;
+}
+
+template <int tIntegerBits>
+FixedPoint<tIntegerBits> operator+(FixedPoint<tIntegerBits> a, FixedPoint<tIntegerBits> b)
+{
+ return FixedPoint<tIntegerBits>::FromRaw((a.raw() + b.raw()));
+}
+template <int tIntegerBits>
+FixedPoint<tIntegerBits> operator-(FixedPoint<tIntegerBits> a, FixedPoint<tIntegerBits> b)
+{
+ return FixedPoint<tIntegerBits>::FromRaw((a.raw() - b.raw()));
+}
+template <int tIntegerBits>
+FixedPoint<tIntegerBits> operator&(FixedPoint<tIntegerBits> a, FixedPoint<tIntegerBits> b)
+{
+ return FixedPoint<tIntegerBits>::FromRaw((a.raw() & b.raw()));
+}
+
+// Rescale changes the number of IntegerBits and updates the underlying
+// raw integer value accordingly.
+template <int tIntegerBitsDst, int tIntegerBitsSrc>
+FixedPoint<tIntegerBitsDst> Rescale(FixedPoint<tIntegerBitsSrc> x)
+{
+ static constexpr int kExponent = tIntegerBitsSrc - tIntegerBitsDst;
+ FixedPoint<tIntegerBitsDst> result;
+ result.raw() = SaturatingRoundingMultiplyByPOT<kExponent>(x.raw());
+ return result;
+}
+
+// Implementation of exponential function.
+
+// Returns exp(x) for x in [-1/4, 0).
+inline FixedPoint<0> exp_on_interval_between_negative_one_quarter_and_0_excl(FixedPoint<0> a)
+{
+ typedef FixedPoint<0> F;
+ const F constant_term = F::FromScalarRaw(RoundingDivideByPOT(1895147668, 0));
+ const F constant_1_over_3 = F::FromScalarRaw(RoundingDivideByPOT(715827883, 0));
+ // We're evaluating a Taylor expansion around -1/8, so we do the change of
+ // variable: x = a + 1/8.
+ // In fixed-point with 0 integer bits, 1/8 is represented by 1 << 28.
+ F x = a + F::template ConstantPOT<-3>();
+ F x2 = x * x;
+ F x3 = x2 * x;
+ F x4 = x2 * x2;
+ F x4_over_4 = F::FromScalarRaw(SaturatingRoundingMultiplyByPOT<-2>(x4.raw()));
+ F x4_over_24_plus_x3_over_6_plus_x2_over_2 = F::FromScalarRaw(
+ SaturatingRoundingMultiplyByPOT<-1>((((x4_over_4 + x3) * constant_1_over_3) + x2).raw()));
+ return (constant_term + constant_term * (x + x4_over_24_plus_x3_over_6_plus_x2_over_2));
+}
+
+// Returns exp(x) for x < 0.
+template <int tIntegerBits> FixedPoint<0> exp_on_negative_values(FixedPoint<tIntegerBits> a)
+{
+ typedef FixedPoint<tIntegerBits> InputF;
+ typedef FixedPoint<0> ResultF;
+ static constexpr int kFractionalBits = InputF::kFractionalBits;
+ static constexpr int kIntegerBits = InputF::kIntegerBits;
+ const InputF kOneQuarter = InputF::template ConstantPOT<-2>();
+ InputF mask = kOneQuarter - InputF::FromScalarRaw(1);
+ InputF a_mod_quarter_minus_one_quarter = (a & mask) - kOneQuarter;
+ ResultF result = exp_on_interval_between_negative_one_quarter_and_0_excl(
+ Rescale<0>(a_mod_quarter_minus_one_quarter));
+ int32_t remainder = (a_mod_quarter_minus_one_quarter - a).raw();
+
+#define GEMMLOWP_EXP_BARREL_SHIFTER(Exponent, FixedPointMultiplier) \
+ if (kIntegerBits > Exponent) \
+ { \
+ const ResultF kMultiplier = \
+ ResultF::FromScalarRaw(RoundingDivideByPOT(FixedPointMultiplier, 0)); \
+ static constexpr int kShiftAmount = \
+ ((kIntegerBits > Exponent) ? (kFractionalBits + Exponent) : 0); \
+ result = ((remainder & (1 << kShiftAmount)) ? (result * kMultiplier) : result); \
+ }
+
+ GEMMLOWP_EXP_BARREL_SHIFTER(-2, 1672461947);
+ GEMMLOWP_EXP_BARREL_SHIFTER(-1, 1302514674);
+ GEMMLOWP_EXP_BARREL_SHIFTER(+0, 790015084);
+ GEMMLOWP_EXP_BARREL_SHIFTER(+1, 290630308);
+ GEMMLOWP_EXP_BARREL_SHIFTER(+2, 39332535);
+ GEMMLOWP_EXP_BARREL_SHIFTER(+3, 720401);
+ GEMMLOWP_EXP_BARREL_SHIFTER(+4, 242);
+
+#undef GEMMLOWP_EXP_BARREL_SHIFTER
+
+ static constexpr int clampB = ((kIntegerBits > 5) ? (36 - kIntegerBits) : 0);
+ if (kIntegerBits > 5)
+ {
+ const InputF clamp = InputF::FromScalarRaw(RoundingDivideByPOT(-(1 << clampB), 0));
+ result.raw() = ((a.raw() < clamp.raw()) ? ResultF::Zero().raw() : result.raw());
+ }
+
+ result.raw() = (a.raw() ? result.raw() : ResultF::One().raw());
+ return result;
+}
+
+// Returns 1 / (1 + x) for x in (0, 1).
+inline FixedPoint<0> one_over_one_plus_x_for_x_in_0_1(FixedPoint<0> a)
+{
+ typedef FixedPoint<0> F0;
+ typedef FixedPoint<2> F2;
+ F0 half_denominator = F0::FromScalarRaw(RoundingHalfSum(a.raw(), F0::One().raw()));
+ // Newton-Raphson division
+ // https://en.wikipedia.org/wiki/Division_algorithm#Newton.E2.80.93Raphson_division
+ // Refer to that page for the logic behind the 48/17 and 32/17 constants.
+ const F2 constant_48_over_17 = F2::FromScalarRaw(RoundingDivideByPOT(1515870810, 0));
+ const F2 constant_neg_32_over_17 = F2::FromScalarRaw(RoundingDivideByPOT(-1010580540, 0));
+ F2 x = constant_48_over_17 + half_denominator * constant_neg_32_over_17;
+ for (int i = 0; i < 3; i++)
+ {
+ F2 half_denominator_times_x = half_denominator * x;
+ F2 one_minus_half_denominator_times_x = F2::One() - half_denominator_times_x;
+ x = x + Rescale<2>(x * one_minus_half_denominator_times_x);
+ }
+ return Rescale<0>(ExactMulByPot<-1>(x));
+}
+
+} // namespace gemmlowp
+} // namespace cker
+} // namespace nnfw
+
+#endif // __NNFW_CKER_GEMMLOWP_FIXED_POINT_H__
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