SharedMemory.h

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/*
 * Copyright 1993-2015 NVIDIA Corporation.  All rights reserved.
 *
 * Please refer to the NVIDIA end user license agreement (EULA) associated
 * with this source code for terms and conditions that govern your use of
 * this software. Any use, reproduction, disclosure, or distribution of
 * this software and related documentation outside the terms of the EULA
 * is strictly prohibited.
 *
 */
 
#ifndef _SHAREDMEM_H_
#define _SHAREDMEM_H_
 
//****************************************************************************
// Because dynamically sized shared memory arrays are declared "extern",
// we can't templatize them directly.  To get around this, we declare a
// simple wrapper struct that will declare the extern array with a different
// name depending on the type.  This avoids compiler errors about duplicate
// definitions.
//
// To use dynamically allocated shared memory in a templatized __global__ or
// __device__ function, just replace code like this:
//
//
//  template<class T>
//  __global__ void
//  foo( T* g_idata, T* g_odata)
//  {
//      // Shared mem size is determined by the host app at run time
//      extern __shared__  T sdata[];
//      ...
//      doStuff(sdata);
//      ...
//   }
//
//   With this
//  template<class T>
//  __global__ void
//  foo( T* g_idata, T* g_odata)
//  {
//      // Shared mem size is determined by the host app at run time
//      SharedMemory<T> smem;
//      T* sdata = smem.getPointer();
//      ...
//      doStuff(sdata);
//      ...
//   }
//****************************************************************************
 
// This is the un-specialized struct.  Note that we prevent instantiation of this
// struct by putting an undefined symbol in the function body so it won't compile.
template <typename T>
struct SharedMemory
{
    // Ensure that we won't compile any un-specialized types
    __device__ T *getPointer()
    {
        extern __device__ void error(void);
        error();
        return NULL;
    }
};
 
// Following are the specializations for the following types.
// int, uint, char, uchar, short, ushort, long, ulong, bool, float, and double
// One could also specialize it for user-defined types.
 
template <>
struct SharedMemory <int>
{
    __device__ int *getPointer()
    {
        extern __shared__ int s_int[];
        return s_int;
    }
};
 
template <>
struct SharedMemory <unsigned int>
{
    __device__ unsigned int *getPointer()
    {
        extern __shared__ unsigned int s_uint[];
        return s_uint;
    }
};
 
template <>
struct SharedMemory <char>
{
    __device__ char *getPointer()
    {
        extern __shared__ char s_char[];
        return s_char;
    }
};
 
template <>
struct SharedMemory <unsigned char>
{
    __device__ unsigned char *getPointer()
    {
        extern __shared__ unsigned char s_uchar[];
        return s_uchar;
    }
};
 
template <>
struct SharedMemory <short>
{
    __device__ short *getPointer()
    {
        extern __shared__ short s_short[];
        return s_short;
    }
};
 
template <>
struct SharedMemory <unsigned short>
{
    __device__ unsigned short *getPointer()
    {
        extern __shared__ unsigned short s_ushort[];
        return s_ushort;
    }
};
 
template <>
struct SharedMemory <long>
{
    __device__ long *getPointer()
    {
        extern __shared__ long s_long[];
        return s_long;
    }
};
 
template <>
struct SharedMemory <unsigned long>
{
    __device__ unsigned long *getPointer()
    {
        extern __shared__ unsigned long s_ulong[];
        return s_ulong;
    }
};
 
template <>
struct SharedMemory <bool>
{
    __device__ bool *getPointer()
    {
        extern __shared__ bool s_bool[];
        return s_bool;
    }
};
 
template <>
struct SharedMemory <float>
{
    __device__ float *getPointer()
    {
        extern __shared__ float s_float[];
        return s_float;
    }
};
 
template <>
struct SharedMemory <double>
{
    __device__ double *getPointer()
    {
        extern __shared__ double s_double[];
        return s_double;
    }
};
 
 
#endif //_SHAREDMEM_H_