cub/block/block_shuffle.cuh
File members: cub/block/block_shuffle.cuh
/******************************************************************************
* Copyright (c) 2011, Duane Merrill. All rights reserved.
* Copyright (c) 2011-2018, NVIDIA CORPORATION. All rights reserved.
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#pragma once
#include <cub/config.cuh>
#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
# pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
# pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
# pragma system_header
#endif // no system header
#include <cub/util_ptx.cuh>
#include <cub/util_type.cuh>
CUB_NAMESPACE_BEGIN
template <typename T, int BLOCK_DIM_X, int BLOCK_DIM_Y = 1, int BLOCK_DIM_Z = 1, int LEGACY_PTX_ARCH = 0>
class BlockShuffle
{
private:
enum
{
BLOCK_THREADS = BLOCK_DIM_X * BLOCK_DIM_Y * BLOCK_DIM_Z,
LOG_WARP_THREADS = CUB_LOG_WARP_THREADS(0),
WARP_THREADS = 1 << LOG_WARP_THREADS,
WARPS = (BLOCK_THREADS + WARP_THREADS - 1) / WARP_THREADS,
};
using _TempStorage = T[BLOCK_THREADS];
public:
struct TempStorage : Uninitialized<_TempStorage>
{};
private:
_TempStorage& temp_storage;
unsigned int linear_tid;
_CCCL_DEVICE _CCCL_FORCEINLINE _TempStorage& PrivateStorage()
{
__shared__ _TempStorage private_storage;
return private_storage;
}
public:
_CCCL_DEVICE _CCCL_FORCEINLINE BlockShuffle()
: temp_storage(PrivateStorage())
, linear_tid(RowMajorTid(BLOCK_DIM_X, BLOCK_DIM_Y, BLOCK_DIM_Z))
{}
_CCCL_DEVICE _CCCL_FORCEINLINE BlockShuffle(TempStorage& temp_storage)
: temp_storage(temp_storage.Alias())
, linear_tid(RowMajorTid(BLOCK_DIM_X, BLOCK_DIM_Y, BLOCK_DIM_Z))
{}
_CCCL_DEVICE _CCCL_FORCEINLINE void Offset(T input, T& output, int distance = 1)
{
temp_storage[linear_tid] = input;
CTA_SYNC();
const int offset_tid = static_cast<int>(linear_tid) + distance;
if ((offset_tid >= 0) && (offset_tid < BLOCK_THREADS))
{
output = temp_storage[static_cast<size_t>(offset_tid)];
}
}
_CCCL_DEVICE _CCCL_FORCEINLINE void Rotate(T input, T& output, unsigned int distance = 1)
{
temp_storage[linear_tid] = input;
CTA_SYNC();
unsigned int offset = linear_tid + distance;
if (offset >= BLOCK_THREADS)
{
offset -= BLOCK_THREADS;
}
output = temp_storage[offset];
}
template <int ITEMS_PER_THREAD>
_CCCL_DEVICE _CCCL_FORCEINLINE void Up(T (&input)[ITEMS_PER_THREAD], T (&prev)[ITEMS_PER_THREAD])
{
temp_storage[linear_tid] = input[ITEMS_PER_THREAD - 1];
CTA_SYNC();
#pragma unroll
for (int ITEM = ITEMS_PER_THREAD - 1; ITEM > 0; --ITEM)
{
prev[ITEM] = input[ITEM - 1];
}
if (linear_tid > 0)
{
prev[0] = temp_storage[linear_tid - 1];
}
}
template <int ITEMS_PER_THREAD>
_CCCL_DEVICE _CCCL_FORCEINLINE void Up(T (&input)[ITEMS_PER_THREAD], T (&prev)[ITEMS_PER_THREAD], T& block_suffix)
{
Up(input, prev);
block_suffix = temp_storage[BLOCK_THREADS - 1];
}
template <int ITEMS_PER_THREAD>
_CCCL_DEVICE _CCCL_FORCEINLINE void Down(T (&input)[ITEMS_PER_THREAD], T (&prev)[ITEMS_PER_THREAD])
{
temp_storage[linear_tid] = input[0];
CTA_SYNC();
#pragma unroll
for (int ITEM = 0; ITEM < ITEMS_PER_THREAD - 1; ITEM++)
{
prev[ITEM] = input[ITEM + 1];
}
if (linear_tid < BLOCK_THREADS - 1)
{
prev[ITEMS_PER_THREAD - 1] = temp_storage[linear_tid + 1];
}
}
template <int ITEMS_PER_THREAD>
_CCCL_DEVICE _CCCL_FORCEINLINE void Down(T (&input)[ITEMS_PER_THREAD], T (&prev)[ITEMS_PER_THREAD], T& block_prefix)
{
Down(input, prev);
block_prefix = temp_storage[0];
}
};
CUB_NAMESPACE_END