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43 
44 #pragma once
45 
46 #ifndef __OPENCV_CUDEV_BLOCK_SCAN_HPP__
47 #define __OPENCV_CUDEV_BLOCK_SCAN_HPP__
48 
49 #include "../common.hpp"
50 #include "../warp/scan.hpp"
51 
52 namespace cv { namespace cudev {
53 
54 //! @addtogroup cudev
55 //! @{
56 
57 template <int THREADS_NUM, typename T>
blockScanInclusive(T data,volatile T * smem,uint tid)58 __device__ T blockScanInclusive(T data, volatile T* smem, uint tid)
59 {
60     if (THREADS_NUM > WARP_SIZE)
61     {
62         // bottom-level inclusive warp scan
63         T warpResult = warpScanInclusive(data, smem, tid);
64 
65         __syncthreads();
66 
67         // save top elements of each warp for exclusive warp scan
68         // sync to wait for warp scans to complete (because s_Data is being overwritten)
69         if ((tid & (WARP_SIZE - 1)) == (WARP_SIZE - 1))
70         {
71             smem[tid >> LOG_WARP_SIZE] = warpResult;
72         }
73 
74         __syncthreads();
75 
76         if (tid < (THREADS_NUM / WARP_SIZE))
77         {
78             // grab top warp elements
79             T val = smem[tid];
80 
81             // calculate exclusive scan and write back to shared memory
82             smem[tid] = warpScanExclusive(val, smem, tid);
83         }
84 
85         __syncthreads();
86 
87         // return updated warp scans with exclusive scan results
88         return warpResult + smem[tid >> LOG_WARP_SIZE];
89     }
90     else
91     {
92         return warpScanInclusive(data, smem, tid);
93     }
94 }
95 
96 template <int THREADS_NUM, typename T>
blockScanExclusive(T data,volatile T * smem,uint tid)97 __device__ __forceinline__ T blockScanExclusive(T data, volatile T* smem, uint tid)
98 {
99     return blockScanInclusive<THREADS_NUM>(data, smem, tid) - data;
100 }
101 
102 //! @}
103 
104 }}
105 
106 #endif
107