SpuDoubleBuffer.h

#ifndef DOUBLE_BUFFER_H
#define DOUBLE_BUFFER_H
 
#include "SpuFakeDma.h"
 

template<class T, int size>
class DoubleBuffer
{
#ifdef __CELLOS_LV2__
    T m_buffer0[size] __attribute__ ((aligned (128)));
    T m_buffer1[size] __attribute__ ((aligned (128)));
#else
    T m_buffer0[size];
    T m_buffer1[size];
#endif
    
    T *m_frontBuffer;
    T *m_backBuffer;
 
    unsigned int m_dmaTag;
    bool m_dmaPending;
public:
    bool    isPending() const { return m_dmaPending;}
    DoubleBuffer();
 
    void init ();
 
    // dma get and put commands
    void backBufferDmaGet(uint64_t ea, unsigned int numBytes, unsigned int tag);
    void backBufferDmaPut(uint64_t ea, unsigned int numBytes, unsigned int tag);
 
    // gets pointer to a buffer
    T *getFront();
    T *getBack();
 
    // if back buffer dma was started, wait for it to complete
    // then move back to front and vice versa
    T *swapBuffers();
};
 
template<class T, int size>
DoubleBuffer<T,size>::DoubleBuffer()
{
    init ();
}
 
template<class T, int size>
void DoubleBuffer<T,size>::init()
{
    this->m_dmaPending = false;
    this->m_frontBuffer = &this->m_buffer0[0];
    this->m_backBuffer = &this->m_buffer1[0];
}
 
template<class T, int size>
void
DoubleBuffer<T,size>::backBufferDmaGet(uint64_t ea, unsigned int numBytes, unsigned int tag)
{
    m_dmaPending = true;
    m_dmaTag = tag;
    cellDmaLargeGet(m_backBuffer, ea, numBytes, tag, 0, 0);
}
 
template<class T, int size>
void
DoubleBuffer<T,size>::backBufferDmaPut(uint64_t ea, unsigned int numBytes, unsigned int tag)
{
    m_dmaPending = true;
    m_dmaTag = tag;
    cellDmaLargePut(m_backBuffer, ea, numBytes, tag, 0, 0);
}
 
template<class T, int size>
T *
DoubleBuffer<T,size>::getFront()
{
    return m_frontBuffer;
}
 
template<class T, int size>
T *
DoubleBuffer<T,size>::getBack()
{
    return m_backBuffer;
}
 
template<class T, int size>
T *
DoubleBuffer<T,size>::swapBuffers()
{
    if (m_dmaPending)
    {
        cellDmaWaitTagStatusAll(1<<m_dmaTag);
        m_dmaPending = false;
    }
 
    T *tmp = m_backBuffer;
    m_backBuffer = m_frontBuffer;
    m_frontBuffer = tmp;
 
    return m_frontBuffer;
}
 
#endif