mirror of https://github.com/openXC7/prjxray.git
70 lines
1.5 KiB
C++
70 lines
1.5 KiB
C++
/*
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* Copyright (C) 2017-2020 The Project X-Ray Authors.
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*
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* Use of this source code is governed by a ISC-style
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* license that can be found in the LICENSE file or at
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* https://opensource.org/licenses/ISC
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*
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* SPDX-License-Identifier: ISC
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*/
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#include <prjxray/xilinx/xc7series/ecc.h>
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#include <cassert>
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#include <cstdio>
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namespace prjxray {
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namespace xilinx {
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namespace xc7series {
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constexpr size_t kECCFrameNumber = 0x32;
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uint32_t icap_ecc(uint32_t idx, uint32_t data, uint32_t ecc) {
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uint32_t val = idx * 32; // bit offset
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if (idx > 0x25) // avoid 0x800
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val += 0x1360;
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else if (idx > 0x6) // avoid 0x400
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val += 0x1340;
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else // avoid lower
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val += 0x1320;
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if (idx == 0x32) // mask ECC
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data &= 0xFFFFE000;
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for (int i = 0; i < 32; i++) {
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if (data & 1)
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ecc ^= val + i;
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data >>= 1;
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}
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if (idx == 0x64) { // last index
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uint32_t v = ecc & 0xFFF;
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v ^= v >> 8;
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v ^= v >> 4;
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v ^= v >> 2;
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v ^= v >> 1;
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ecc ^= (v & 1) << 12; // parity
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}
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return ecc;
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}
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static uint32_t calculateECC(const std::vector<uint32_t>& data) {
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uint32_t ecc = 0;
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for (size_t ii = 0; ii < data.size(); ++ii) {
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ecc = xc7series::icap_ecc(ii, data[ii], ecc);
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}
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return ecc;
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}
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void updateECC(std::vector<uint32_t>& data) {
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assert(data.size() >= kECCFrameNumber);
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// Replace the old ECC with the new.
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data[kECCFrameNumber] &= 0xFFFFE000;
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data[kECCFrameNumber] |= (calculateECC(data) & 0x1FFF);
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}
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} // namespace xc7series
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} // namespace xilinx
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} // namespace prjxray
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