| // |
| // Copyright © 2017 Arm Ltd. All rights reserved. |
| // SPDX-License-Identifier: MIT |
| // |
| |
| #include "ConvImpl.hpp" |
| |
| #include <boost/assert.hpp> |
| |
| #include <cmath> |
| #include <limits> |
| |
| namespace armnn |
| { |
| |
| QuantizedMultiplierSmallerThanOne::QuantizedMultiplierSmallerThanOne(float multiplier) |
| { |
| BOOST_ASSERT(multiplier >= 0.0f && multiplier < 1.0f); |
| if (multiplier == 0.0f) |
| { |
| m_Multiplier = 0; |
| m_RightShift = 0; |
| } |
| else |
| { |
| const double q = std::frexp(multiplier, &m_RightShift); |
| m_RightShift = -m_RightShift; |
| int64_t qFixed = static_cast<int64_t>(std::round(q * (1ll << 31))); |
| BOOST_ASSERT(qFixed <= (1ll << 31)); |
| if (qFixed == (1ll << 31)) |
| { |
| qFixed /= 2; |
| --m_RightShift; |
| } |
| BOOST_ASSERT(m_RightShift >= 0); |
| BOOST_ASSERT(qFixed <= std::numeric_limits<int32_t>::max()); |
| m_Multiplier = static_cast<int32_t>(qFixed); |
| } |
| } |
| |
| int32_t QuantizedMultiplierSmallerThanOne::operator*(int32_t rhs) const |
| { |
| int32_t x = SaturatingRoundingDoublingHighMul(rhs, m_Multiplier); |
| return RoundingDivideByPOT(x, m_RightShift); |
| } |
| |
| int32_t QuantizedMultiplierSmallerThanOne::SaturatingRoundingDoublingHighMul(int32_t a, int32_t b) |
| { |
| // Check for overflow. |
| if (a == b && a == std::numeric_limits<int32_t>::min()) |
| { |
| return std::numeric_limits<int32_t>::max(); |
| } |
| 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<std::int32_t>((ab_64 + nudge) / (1ll << 31)); |
| return ab_x2_high32; |
| } |
| |
| int32_t QuantizedMultiplierSmallerThanOne::RoundingDivideByPOT(int32_t x, int exponent) |
| { |
| BOOST_ASSERT(exponent >= 0 && exponent <= 31); |
| int32_t mask = (1 << exponent) - 1; |
| int32_t remainder = x & mask; |
| int32_t threshold = (mask >> 1) + (x < 0 ? 1 : 0); |
| return (x >> exponent) + (remainder > threshold ? 1 : 0); |
| } |
| |
| } //namespace armnn |