src/gallium/drivers/swr/rasterizer/core/fifo.hpp

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  23 * @file fifo.hpp
  24 *
  25 * @brief Definitions for our fifos used for thread communication.
  26 *
  27 ******************************************************************************/
  28 #pragma once
  29
  30
  31 #include "common/os.h"
  32 #include "arena.h"
  33
  34 #include <vector>
  35 #include <cassert>
  36
  37 template<class T>
  38 struct QUEUE
  39 {
  40     OSALIGNLINE(volatile uint32_t) mLock{ 0 };
  41     OSALIGNLINE(volatile uint32_t) mNumEntries{ 0 };
  42     std::vector<T*> mBlocks;
  43     T* mCurBlock{ nullptr };
  44     uint32_t mHead{ 0 };
  45     uint32_t mTail{ 0 };
  46     uint32_t mCurBlockIdx{ 0 };
  47
  48     // power of 2
  49     static const uint32_t mBlockSizeShift = 6;
  50     static const uint32_t mBlockSize = 1 << mBlockSizeShift;
  51
  52     void clear(Arena& arena)
  53     {
  54         mHead = 0;
  55         mTail = 0;
  56         mBlocks.clear();
  57         T* pNewBlock = (T*)arena.Alloc(sizeof(T)*mBlockSize);
  58         mBlocks.push_back(pNewBlock);
  59         mCurBlock = pNewBlock;
  60         mCurBlockIdx = 0;
  61
  62         mNumEntries = 0;
  63         _ReadWriteBarrier();
  64         mLock = 0;
  65     }
  66
  67     uint32_t getNumQueued()
  68     {
  69         return mNumEntries;
  70     }
  71
  72     bool tryLock()
  73     {
  74         if (mLock)
  75         {
  76             return false;
  77         }
  78
  79         // try to lock the FIFO
  80         LONG initial = InterlockedCompareExchange(&mLock, 1, 0);
  81         return (initial == 0);
  82     }
  83
  84     void unlock()
  85     {
  86         mLock = 0;
  87     }
  88
  89     T* peek()
  90     {
  91         if (mNumEntries == 0)
  92         {
  93             return nullptr;
  94         }
  95         uint32_t block = mHead >> mBlockSizeShift;
  96         return &mBlocks[block][mHead & (mBlockSize-1)];
  97     }
  98
  99     void dequeue_noinc()
 100     {
 101         mHead ++;
 102         mNumEntries --;
 103     }
 104
 105     bool enqueue_try_nosync(Arena& arena, const T* entry)
 106     {
 107         memcpy(&mCurBlock[mTail], entry, sizeof(T));
 108
 109         mTail ++;
 110         if (mTail == mBlockSize)
 111         {
 112             if (++mCurBlockIdx < mBlocks.size())
 113             {
 114                 mCurBlock = mBlocks[mCurBlockIdx];
 115             }
 116             else
 117             {
 118                 T* newBlock = (T*)arena.Alloc(sizeof(T)*mBlockSize);
 119                 SWR_ASSERT(newBlock);
 120
 121                 mBlocks.push_back(newBlock);
 122                 mCurBlock = newBlock;
 123             }
 124
 125             mTail = 0;
 126         }
 127
 128         mNumEntries ++;
 129         return true;
 130     }
 131
 132     void destroy()
 133     {
 134     }
 135
 136 };