mirror of https://github.com/status-im/leopard.git
160 lines
4.9 KiB
C++
160 lines
4.9 KiB
C++
/*
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Copyright (c) 2017 Christopher A. Taylor. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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* Neither the name of Leopard-RS nor the names of its contributors may be
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used to endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include "LeopardCommon.h"
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#ifdef LEO_HAS_FF8
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/*
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8-bit Finite Field Math
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This finite field contains 256 elements and so each element is one byte.
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This library is designed for data that is a multiple of 64 bytes in size.
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Algorithms are described in LeopardCommon.h
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*/
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namespace leopard { namespace ff8 {
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//------------------------------------------------------------------------------
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// Datatypes and Constants
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// Finite field element type
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typedef uint8_t ffe_t;
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// Number of bits per element
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static const unsigned kBits = 8;
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// Finite field order: Number of elements in the field
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static const unsigned kOrder = 256;
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// Modulus for field operations
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static const ffe_t kModulus = 255;
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// LFSR Polynomial that generates the field elements
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static const unsigned kPolynomial = 0x11D;
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//------------------------------------------------------------------------------
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// Fast Walsh-Hadamard Transform (FWHT) (mod kModulus)
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// Transform for a variable number of elements
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// m_truncated: Number of elements that are non-zero at the front of data
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void FWHT(ffe_t* data, const unsigned m, const unsigned m_truncated);
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//------------------------------------------------------------------------------
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// Multiplies
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// x[] = exp(log(y[]) + log_m)
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// mul_mem
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void mul_mem(
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void * LEO_RESTRICT x, const void * LEO_RESTRICT y,
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ffe_t log_m, uint64_t bytes);
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//------------------------------------------------------------------------------
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// FFT Operations
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/*
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Precondition: log_m != kModulus
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x[] ^= exp(log(y[]) + log_m)
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y[] ^= x[]
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*/
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void fft_butterfly(
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void * LEO_RESTRICT x, void * LEO_RESTRICT y,
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ffe_t log_m, uint64_t bytes);
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#ifdef LEO_USE_VECTOR4_OPT
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// Unroll 4 rows at a time
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void fft_butterfly4(
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void * LEO_RESTRICT x_0, void * LEO_RESTRICT y_0,
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void * LEO_RESTRICT x_1, void * LEO_RESTRICT y_1,
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void * LEO_RESTRICT x_2, void * LEO_RESTRICT y_2,
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void * LEO_RESTRICT x_3, void * LEO_RESTRICT y_3,
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ffe_t log_m, uint64_t bytes);
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#endif // LEO_USE_VECTOR4_OPT
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//------------------------------------------------------------------------------
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// IFFT Operations
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/*
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Precondition: log_m != kModulus
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y[] ^= x[]
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x[] ^= exp(log(y[]) + log_m)
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*/
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void ifft_butterfly(
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void * LEO_RESTRICT x, void * LEO_RESTRICT y,
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ffe_t log_m, uint64_t bytes);
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//------------------------------------------------------------------------------
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// Reed-Solomon Encode
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void ReedSolomonEncode(
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uint64_t buffer_bytes,
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unsigned original_count,
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unsigned recovery_count,
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unsigned m, // = NextPow2(recovery_count) * 2 = work_count
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void* const * const data,
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void** work); // Size of GetEncodeWorkCount()
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//------------------------------------------------------------------------------
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// Reed-Solomon Decode
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void ReedSolomonDecode(
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uint64_t buffer_bytes,
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unsigned original_count,
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unsigned recovery_count,
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unsigned m, // = NextPow2(recovery_count)
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unsigned n, // = NextPow2(m + original_count) = work_count
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void* const * const original, // original_count entries
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void* const * const recovery, // recovery_count entries
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void** work); // n entries
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//------------------------------------------------------------------------------
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// API
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// Returns false if the self-test fails
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bool Initialize();
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}} // namespace leopard::ff8
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#endif // LEO_HAS_FF8
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