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20 * @brief xRAN BFP compression/decompression U-plane implementation and interface functions
22 * @file xran_compression.cpp
23 * @ingroup group_source_xran
24 * @author Intel Corporation
27 #include "xran_compression.hpp"
28 #include "xran_bfp_utils.hpp"
29 #include "xran_bfp_byte_packing_utils.hpp"
30 #include "xran_compression.h"
33 #include <immintrin.h>
38 /// Namespace constants
39 const int k_numREReal = 24; /// 12 IQ pairs
42 /// Compute exponent value for a set of 16 RB from the maximum absolute value.
43 /// Max Abs operates in a loop, executing 4 RB per iteration. The results are
44 /// packed into the final output register.
46 computeExponent_16RB(const BlockFloatCompander::ExpandedData& dataIn, const __m512i totShiftBits)
48 __m512i maxAbs = __m512i();
49 const __m512i* rawData = reinterpret_cast<const __m512i*>(dataIn.dataExpanded);
50 /// Max Abs loop operates on 4RB at a time
52 for (int n = 0; n < 4; ++n)
54 /// Re-order and vertical max abs
55 auto maxAbsVert = BlockFloatCompander::maxAbsVertical4RB(rawData[3 * n + 0], rawData[3 * n + 1], rawData[3 * n + 2]);
56 /// Horizontal max abs
57 auto maxAbsHorz = BlockFloatCompander::horizontalMax4x16(maxAbsVert);
58 /// Pack these 4 values into maxAbs
59 maxAbs = BlockFloatCompander::slidePermute(maxAbsHorz, maxAbs, n);
61 /// Calculate exponent
62 const auto maxAbs32 = BlockFloatCompander::maskUpperWord(maxAbs);
63 return BlockFloatCompander::expLzCnt(maxAbs32, totShiftBits);
67 /// Compute exponent value for a set of 4 RB from the maximum absolute value.
68 /// Note that we do not need to perform any packing of result as we are only
69 /// computing 4 RB. The appropriate offset is taken later when extracting the
72 computeExponent_4RB(const BlockFloatCompander::ExpandedData& dataIn, const __m512i totShiftBits)
74 const __m512i* rawData = reinterpret_cast<const __m512i*>(dataIn.dataExpanded);
75 /// Re-order and vertical max abs
76 const auto maxAbsVert = BlockFloatCompander::maxAbsVertical4RB(rawData[0], rawData[1], rawData[2]);
77 /// Horizontal max abs
78 const auto maxAbsHorz = BlockFloatCompander::horizontalMax4x16(maxAbsVert);
79 /// Calculate exponent
80 const auto maxAbs = BlockFloatCompander::maskUpperWord(maxAbsHorz);
81 return BlockFloatCompander::expLzCnt(maxAbs, totShiftBits);
85 /// Compute exponent value for 1 RB from the maximum absolute value.
86 /// This works with horizontal max abs only, and needs to include a
87 /// step to select the final exponent from the 4 lanes.
89 computeExponent_1RB(const BlockFloatCompander::ExpandedData& dataIn, const __m512i totShiftBits)
91 const __m512i* rawData = reinterpret_cast<const __m512i*>(dataIn.dataExpanded);
93 const auto rawDataAbs = _mm512_abs_epi16(rawData[0]);
94 /// No need to do a full horizontal max operation here, just do a max IQ step,
95 /// compute the exponents and then use a reduce max over all exponent values. This
96 /// is the fastest way to handle a single RB.
97 const auto rawAbsIQSwap = _mm512_rol_epi32(rawDataAbs, BlockFloatCompander::k_numBitsIQ);
98 const auto maxAbsIQ = _mm512_max_epi16(rawDataAbs, rawAbsIQSwap);
99 /// Calculate exponent
100 const auto maxAbsIQ32 = BlockFloatCompander::maskUpperWord(maxAbsIQ);
101 const auto exps = BlockFloatCompander::expLzCnt(maxAbsIQ32, totShiftBits);
102 /// At this point we have exponent values for the maximum of each IQ pair.
103 /// Run a reduce max step to compute the maximum exponent value in the first
104 /// three lanes - this will give the desired exponent for this RB.
105 constexpr uint16_t k_expMsk = 0x0FFF;
106 return (uint8_t)_mm512_mask_reduce_max_epi32(k_expMsk, exps);
110 /// Apply compression to 1 RB
111 template<BlockFloatCompander::PackFunction networkBytePack>
113 applyCompressionN_1RB(const BlockFloatCompander::ExpandedData& dataIn, BlockFloatCompander::CompressedData* dataOut,
114 const int numREOffset, const uint8_t thisExp, const int thisRBExpAddr, const uint16_t rbWriteMask)
116 /// Get AVX512 pointer aligned to desired RB
117 const __m512i* rawDataIn = reinterpret_cast<const __m512i*>(dataIn.dataExpanded + numREOffset);
118 /// Apply the exponent shift
119 const auto compData = _mm512_srai_epi16(*rawDataIn, thisExp);
120 /// Pack compressed data network byte order
121 const auto compDataBytePacked = networkBytePack(compData);
122 /// Store exponent first
123 dataOut->dataCompressed[thisRBExpAddr] = thisExp;
124 /// Now have 1 RB worth of bytes separated into 3 chunks (1 per lane)
125 /// Use three offset stores to join
126 _mm_mask_storeu_epi8(dataOut->dataCompressed + thisRBExpAddr + 1, rbWriteMask, _mm512_extracti64x2_epi64(compDataBytePacked, 0));
127 _mm_mask_storeu_epi8(dataOut->dataCompressed + thisRBExpAddr + 1 + dataIn.iqWidth, rbWriteMask, _mm512_extracti64x2_epi64(compDataBytePacked, 1));
128 _mm_mask_storeu_epi8(dataOut->dataCompressed + thisRBExpAddr + 1 + (2 * dataIn.iqWidth), rbWriteMask, _mm512_extracti64x2_epi64(compDataBytePacked, 2));
132 /// Apply 9, 10, or 12bit compression to 16 RB
133 template<BlockFloatCompander::PackFunction networkBytePack>
135 compressN_16RB(const BlockFloatCompander::ExpandedData& dataIn, BlockFloatCompander::CompressedData* dataOut,
136 const __m512i totShiftBits, const int totNumBytesPerRB, const uint16_t rbWriteMask)
138 const auto exponents = computeExponent_16RB(dataIn, totShiftBits);
140 for (int n = 0; n < 16; ++n)
142 applyCompressionN_1RB<networkBytePack>(dataIn, dataOut, n * k_numREReal, ((uint8_t*)&exponents)[n * 4], n * totNumBytesPerRB, rbWriteMask);
147 /// Apply 9, 10, or 12bit compression to 4 RB
148 template<BlockFloatCompander::PackFunction networkBytePack>
150 compressN_4RB(const BlockFloatCompander::ExpandedData& dataIn, BlockFloatCompander::CompressedData* dataOut,
151 const __m512i totShiftBits, const int totNumBytesPerRB, const uint16_t rbWriteMask)
153 const auto exponents = computeExponent_4RB(dataIn, totShiftBits);
155 for (int n = 0; n < 4; ++n)
157 applyCompressionN_1RB<networkBytePack>(dataIn, dataOut, n * k_numREReal, ((uint8_t*)&exponents)[n * 16], n * totNumBytesPerRB, rbWriteMask);
162 /// Apply 9, 10, or 12bit compression to 1 RB
163 template<BlockFloatCompander::PackFunction networkBytePack>
165 compressN_1RB(const BlockFloatCompander::ExpandedData& dataIn, BlockFloatCompander::CompressedData* dataOut,
166 const __m512i totShiftBits, const int totNumBytesPerRB, const uint16_t rbWriteMask)
168 const auto thisExponent = computeExponent_1RB(dataIn, totShiftBits);
169 applyCompressionN_1RB<networkBytePack>(dataIn, dataOut, 0, thisExponent, 0, rbWriteMask);
173 /// Calls compression function specific to the number of RB to be executed. For 9, 10, or 12bit iqWidth.
174 template<BlockFloatCompander::PackFunction networkBytePack>
176 compressByAllocN(const BlockFloatCompander::ExpandedData& dataIn, BlockFloatCompander::CompressedData* dataOut,
177 const __m512i totShiftBits, const int totNumBytesPerRB, const uint16_t rbWriteMask)
179 switch (dataIn.numBlocks)
182 compressN_16RB<networkBytePack>(dataIn, dataOut, totShiftBits, totNumBytesPerRB, rbWriteMask);
186 compressN_4RB<networkBytePack>(dataIn, dataOut, totShiftBits, totNumBytesPerRB, rbWriteMask);
190 compressN_1RB<networkBytePack>(dataIn, dataOut, totShiftBits, totNumBytesPerRB, rbWriteMask);
196 /// Apply compression to 1 RB
198 applyCompression8_1RB(const BlockFloatCompander::ExpandedData& dataIn, BlockFloatCompander::CompressedData* dataOut,
199 const int numREOffset, const uint8_t thisExp, const int thisRBExpAddr)
201 /// Get AVX512 pointer aligned to desired RB
202 const __m512i* rawDataIn = reinterpret_cast<const __m512i*>(dataIn.dataExpanded + numREOffset);
203 /// Apply the exponent shift
204 const auto compData = _mm512_srai_epi16(*rawDataIn, thisExp);
205 /// Store exponent first
206 dataOut->dataCompressed[thisRBExpAddr] = thisExp;
207 /// Now have 1 RB worth of bytes separated into 3 chunks (1 per lane)
208 /// Use three offset stores to join
209 constexpr uint32_t k_rbMask = 0x00FFFFFF; // Write mask for 1RB (24 values)
210 _mm256_mask_storeu_epi8(dataOut->dataCompressed + thisRBExpAddr + 1, k_rbMask, _mm512_cvtepi16_epi8(compData));
214 /// 8bit RB compression loop for 16 RB
216 compress8_16RB(const BlockFloatCompander::ExpandedData& dataIn, BlockFloatCompander::CompressedData* dataOut, const __m512i totShiftBits)
218 const auto exponents = computeExponent_16RB(dataIn, totShiftBits);
220 for (int n = 0; n < 16; ++n)
222 applyCompression8_1RB(dataIn, dataOut, n * k_numREReal, ((uint8_t*)&exponents)[n * 4], n * (k_numREReal + 1));
227 /// 8bit RB compression loop for 4 RB
229 compress8_4RB(const BlockFloatCompander::ExpandedData& dataIn, BlockFloatCompander::CompressedData* dataOut, const __m512i totShiftBits)
231 const auto exponents = computeExponent_4RB(dataIn, totShiftBits);
233 for (int n = 0; n < 4; ++n)
235 applyCompression8_1RB(dataIn, dataOut, n * k_numREReal, ((uint8_t*)&exponents)[n * 16], n * (k_numREReal + 1));
240 /// 8bit RB compression loop for 4 RB
242 compress8_1RB(const BlockFloatCompander::ExpandedData& dataIn, BlockFloatCompander::CompressedData* dataOut, const __m512i totShiftBits)
244 const auto thisExponent = computeExponent_1RB(dataIn, totShiftBits);
245 applyCompression8_1RB(dataIn, dataOut, 0, thisExponent, 0);
249 /// Calls compression function specific to the number of RB to be executed. For 8 bit iqWidth.
251 compressByAlloc8(const BlockFloatCompander::ExpandedData& dataIn, BlockFloatCompander::CompressedData* dataOut, const __m512i totShiftBits)
253 switch (dataIn.numBlocks)
256 compress8_16RB(dataIn, dataOut, totShiftBits);
260 compress8_4RB(dataIn, dataOut, totShiftBits);
264 compress8_1RB(dataIn, dataOut, totShiftBits);
270 /// Apply compression to 1 RB
271 template<BlockFloatCompander::UnpackFunction networkByteUnpack>
273 applyExpansionN_1RB(const BlockFloatCompander::CompressedData& dataIn, BlockFloatCompander::ExpandedData* dataOut,
274 const int expAddr, const int thisRBAddr, const int maxExpShift)
276 /// Unpack network order packed data
277 const auto dataUnpacked = networkByteUnpack(dataIn.dataCompressed + expAddr + 1);
278 /// Apply exponent scaling (by appropriate arithmetic shift right)
279 const auto dataExpanded = _mm512_srai_epi16(dataUnpacked, maxExpShift - *(dataIn.dataCompressed + expAddr));
280 /// Write expanded data to output
281 static constexpr uint32_t k_WriteMask = 0x00FFFFFF;
282 _mm512_mask_storeu_epi16(dataOut->dataExpanded + thisRBAddr, k_WriteMask, dataExpanded);
286 /// Calls compression function specific to the number of RB to be executed. For 9, 10, or 12bit iqWidth.
287 template<BlockFloatCompander::UnpackFunction networkByteUnpack>
289 expandByAllocN(const BlockFloatCompander::CompressedData& dataIn, BlockFloatCompander::ExpandedData* dataOut,
290 const int totNumBytesPerRB, const int maxExpShift)
292 switch (dataIn.numBlocks)
296 for (int n = 0; n < 16; ++n)
298 applyExpansionN_1RB<networkByteUnpack>(dataIn, dataOut, n * totNumBytesPerRB, n * k_numREReal, maxExpShift);
304 for (int n = 0; n < 4; ++n)
306 applyExpansionN_1RB<networkByteUnpack>(dataIn, dataOut, n * totNumBytesPerRB, n * k_numREReal, maxExpShift);
311 applyExpansionN_1RB<networkByteUnpack>(dataIn, dataOut, 0, 0, maxExpShift);
317 /// Apply expansion to 1 RB and store
319 applyExpansion8_1RB(const BlockFloatCompander::CompressedData& dataIn, BlockFloatCompander::ExpandedData* dataOut,
320 const int expAddr, const int thisRBAddr)
322 const __m256i* rawDataIn = reinterpret_cast<const __m256i*>(dataIn.dataCompressed + expAddr + 1);
323 const auto compData16 = _mm512_cvtepi8_epi16(*rawDataIn);
324 const auto expData = _mm512_slli_epi16(compData16, *(dataIn.dataCompressed + expAddr));
325 constexpr uint8_t k_rbMask64 = 0b00111111; // 64b write mask for 1RB (24 int16 values)
326 _mm512_mask_storeu_epi64(dataOut->dataExpanded + thisRBAddr, k_rbMask64, expData);
330 /// Calls expansion function specific to the number of RB to be executed. For 8 bit iqWidth.
332 expandByAlloc8(const BlockFloatCompander::CompressedData& dataIn, BlockFloatCompander::ExpandedData* dataOut)
334 switch (dataIn.numBlocks)
338 for (int n = 0; n < 16; ++n)
340 applyExpansion8_1RB(dataIn, dataOut, n * (k_numREReal + 1), n * k_numREReal);
346 for (int n = 0; n < 4; ++n)
348 applyExpansion8_1RB(dataIn, dataOut, n * (k_numREReal + 1), n * k_numREReal);
353 applyExpansion8_1RB(dataIn, dataOut, 0, 0);
361 /// Main kernel function for compression.
362 /// Starts by determining iqWidth specific parameters and functions.
364 BlockFloatCompander::BFPCompressUserPlaneAvx512(const ExpandedData& dataIn, CompressedData* dataOut)
366 /// Compensation for extra zeros in 32b leading zero count when computing exponent
367 const auto totShiftBits8 = _mm512_set1_epi32(25);
368 const auto totShiftBits9 = _mm512_set1_epi32(24);
369 const auto totShiftBits10 = _mm512_set1_epi32(23);
370 const auto totShiftBits12 = _mm512_set1_epi32(21);
372 /// Total number of compressed bytes per RB for each iqWidth option
373 constexpr int totNumBytesPerRB9 = 28;
374 constexpr int totNumBytesPerRB10 = 31;
375 constexpr int totNumBytesPerRB12 = 37;
377 /// Compressed data write mask for each iqWidth option
378 constexpr uint16_t rbWriteMask9 = 0x01FF;
379 constexpr uint16_t rbWriteMask10 = 0x03FF;
380 constexpr uint16_t rbWriteMask12 = 0x0FFF;
382 switch (dataIn.iqWidth)
385 BFP_UPlane::compressByAlloc8(dataIn, dataOut, totShiftBits8);
389 BFP_UPlane::compressByAllocN<BlockFloatCompander::networkBytePack9b>(dataIn, dataOut, totShiftBits9, totNumBytesPerRB9, rbWriteMask9);
393 BFP_UPlane::compressByAllocN<BlockFloatCompander::networkBytePack10b>(dataIn, dataOut, totShiftBits10, totNumBytesPerRB10, rbWriteMask10);
397 BFP_UPlane::compressByAllocN<BlockFloatCompander::networkBytePack12b>(dataIn, dataOut, totShiftBits12, totNumBytesPerRB12, rbWriteMask12);
404 /// Main kernel function for expansion.
405 /// Starts by determining iqWidth specific parameters and functions.
407 BlockFloatCompander::BFPExpandUserPlaneAvx512(const CompressedData& dataIn, ExpandedData* dataOut)
409 constexpr int k_totNumBytesPerRB9 = 28;
410 constexpr int k_totNumBytesPerRB10 = 31;
411 constexpr int k_totNumBytesPerRB12 = 37;
413 constexpr int k_maxExpShift9 = 7;
414 constexpr int k_maxExpShift10 = 6;
415 constexpr int k_maxExpShift12 = 4;
417 switch (dataIn.iqWidth)
420 BFP_UPlane::expandByAlloc8(dataIn, dataOut);
424 BFP_UPlane::expandByAllocN<BlockFloatCompander::networkByteUnpack9b>(dataIn, dataOut, k_totNumBytesPerRB9, k_maxExpShift9);
428 BFP_UPlane::expandByAllocN<BlockFloatCompander::networkByteUnpack10b>(dataIn, dataOut, k_totNumBytesPerRB10, k_maxExpShift10);
432 BFP_UPlane::expandByAllocN<BlockFloatCompander::networkByteUnpack12b>(dataIn, dataOut, k_totNumBytesPerRB12, k_maxExpShift12);