// Copyright 2008 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include <cstring>

#include "Common/ChunkFile.h"
#include "Common/CommonFuncs.h"
#include "Common/CommonTypes.h"
#include "Core/HW/GPFifo.h"
#include "Core/HW/Memmap.h"
#include "Core/HW/ProcessorInterface.h"
#include "Core/PowerPC/JitInterface.h"
#include "VideoCommon/CommandProcessor.h"

namespace GPFifo
{
// 32 Byte gather pipe with extra space
// Overfilling is no problem (up to the real limit), CheckGatherPipe will blast the
// contents in nicely sized chunks
//
// Other optimizations to think about:
// - If the GP is NOT linked to the FIFO, just blast to memory byte by word
// - If the GP IS linked to the FIFO, use a fast wrapping buffer and skip writing to memory
//
// Both of these should actually work! Only problem is that we have to decide at run time,
// the same function could use both methods. Compile 2 different versions of each such block?

// More room for the fastmodes
alignas(32) u8 m_gatherPipe[GATHER_PIPE_SIZE * 16];

// pipe counter
u32 m_gatherPipeCount = 0;

void DoState(PointerWrap& p)
{
  p.Do(m_gatherPipe);
  p.Do(m_gatherPipeCount);
}

void Init()
{
  ResetGatherPipe();
  memset(m_gatherPipe, 0, sizeof(m_gatherPipe));
}

bool IsEmpty()
{
  return m_gatherPipeCount == 0;
}

void ResetGatherPipe()
{
  m_gatherPipeCount = 0;
}

static void UpdateGatherPipe()
{
  u32 cnt;
  u8* curMem = Memory::GetPointer(ProcessorInterface::Fifo_CPUWritePointer);
  for (cnt = 0; m_gatherPipeCount >= GATHER_PIPE_SIZE; cnt += GATHER_PIPE_SIZE)
  {
    // copy the GatherPipe
    memcpy(curMem, m_gatherPipe + cnt, GATHER_PIPE_SIZE);
    m_gatherPipeCount -= GATHER_PIPE_SIZE;

    // increase the CPUWritePointer
    if (ProcessorInterface::Fifo_CPUWritePointer == ProcessorInterface::Fifo_CPUEnd)
    {
      ProcessorInterface::Fifo_CPUWritePointer = ProcessorInterface::Fifo_CPUBase;
      curMem = Memory::GetPointer(ProcessorInterface::Fifo_CPUWritePointer);
    }
    else
    {
      curMem += GATHER_PIPE_SIZE;
      ProcessorInterface::Fifo_CPUWritePointer += GATHER_PIPE_SIZE;
    }

    CommandProcessor::GatherPipeBursted();
  }

  // move back the spill bytes
  memmove(m_gatherPipe, m_gatherPipe + cnt, m_gatherPipeCount);
}

void FastCheckGatherPipe()
{
  if (m_gatherPipeCount >= GATHER_PIPE_SIZE)
  {
    UpdateGatherPipe();
  }
}

void CheckGatherPipe()
{
  if (m_gatherPipeCount >= GATHER_PIPE_SIZE)
  {
    UpdateGatherPipe();

    // Profile where slow FIFO writes are occurring.
    JitInterface::CompileExceptionCheck(JitInterface::ExceptionType::EXCEPTIONS_FIFO_WRITE);
  }
}

void Write8(const u8 value)
{
  FastWrite8(value);
  CheckGatherPipe();
}

void Write16(const u16 value)
{
  FastWrite16(value);
  CheckGatherPipe();
}

void Write32(const u32 value)
{
  FastWrite32(value);
  CheckGatherPipe();
}

void Write64(const u64 value)
{
  FastWrite64(value);
  CheckGatherPipe();
}

void FastWrite8(const u8 value)
{
  m_gatherPipe[m_gatherPipeCount] = value;
  ++m_gatherPipeCount;
}

void FastWrite16(u16 value)
{
  value = Common::swap16(value);
  std::memcpy(&m_gatherPipe[m_gatherPipeCount], &value, sizeof(u16));
  m_gatherPipeCount += sizeof(u16);
}

void FastWrite32(u32 value)
{
  value = Common::swap32(value);
  std::memcpy(&m_gatherPipe[m_gatherPipeCount], &value, sizeof(u32));
  m_gatherPipeCount += sizeof(u32);
}

void FastWrite64(u64 value)
{
  value = Common::swap64(value);
  std::memcpy(&m_gatherPipe[m_gatherPipeCount], &value, sizeof(u64));
  m_gatherPipeCount += sizeof(u64);
}

}  // end of namespace GPFifo