cuda-samples/Samples/simpleVoteIntrinsics/simpleVote_kernel.cuh

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/* Copyright (c) 2018, NVIDIA CORPORATION. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
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* * Redistributions of source code must retain the above copyright
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* * Redistributions in binary form must reproduce the above copyright
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* documentation and/or other materials provided with the distribution.
* * Neither the name of NVIDIA CORPORATION nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
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#ifndef SIMPLEVOTE_KERNEL_CU
#define SIMPLEVOTE_KERNEL_CU
////////////////////////////////////////////////////////////////////////////////
// Vote Any/All intrinsic kernel function tests are supported only by CUDA
// capable devices that are CUDA hardware that has SM1.2 or later
// Vote Functions (refer to section 4.4.5 in the CUDA Programming Guide)
////////////////////////////////////////////////////////////////////////////////
// Kernel #1 tests the across-the-warp vote(any) intrinsic.
// If ANY one of the threads (within the warp) of the predicated condition
// returns a non-zero value, then all threads within this warp will return a
// non-zero value
__global__ void VoteAnyKernel1(unsigned int *input, unsigned int *result,
int size) {
int tx = threadIdx.x;
int mask = 0xffffffff;
result[tx] = __any_sync(mask, input[tx]);
}
// Kernel #2 tests the across-the-warp vote(all) intrinsic.
// If ALL of the threads (within the warp) of the predicated condition returns
// a non-zero value, then all threads within this warp will return a non-zero
// value
__global__ void VoteAllKernel2(unsigned int *input, unsigned int *result,
int size) {
int tx = threadIdx.x;
int mask = 0xffffffff;
result[tx] = __all_sync(mask, input[tx]);
}
// Kernel #3 is a directed test for the across-the-warp vote(all) intrinsic.
// This kernel will test for conditions across warps, and within half warps
__global__ void VoteAnyKernel3(bool *info, int warp_size) {
int tx = threadIdx.x;
unsigned int mask = 0xffffffff;
bool *offs = info + (tx * 3);
// The following should hold true for the second and third warp
*offs = __any_sync(mask, (tx >= (warp_size * 3) / 2));
// The following should hold true for the "upper half" of the second warp,
// and all of the third warp
*(offs + 1) = (tx >= (warp_size * 3) / 2 ? true : false);
// The following should hold true for the third warp only
if (__all_sync(mask, (tx >= (warp_size * 3) / 2))) {
*(offs + 2) = true;
}
}
#endif