Function DEV9runFIFO

pcsx2/DEV9/DEV9.cpp:390–435

FIFO counters operate based on the direction set in SPD_R_XFR_CTRL Both might have to set to the same direction for (SPEED <-> HDD) to work

// FIFO counters operate based on the direction set in SPD_R_XFR_CTRL
// Both might have to set to the same direction for (SPEED <-> HDD) to work
void DEV9runFIFO()
{
	const bool iopWrite = dev9.xfr_ctrl & SPD_XFR_WRITE; // IOP writes to FIFO
	const bool hddRead = dev9.if_ctrl & SPD_IF_READ; // HDD writes to FIFO

	const bool iopXfer = (dev9.dma_iop_ptr != nullptr) && (dev9.xfr_ctrl & SPD_XFR_DMAEN);
	const bool hddXfer = dev9.ata->dmaReady && (dev9.if_ctrl & SPD_IF_ATA_DMAEN);

	// Order operations based on iopWrite to ensure DMA has data/space to work with.
	if (iopWrite)
	{
		// Perform DMA from IOP.
		if (iopXfer)
			IOPWriteFIFO();

		// Drain the FIFO
		if (hddXfer && !hddRead)
		{
			HDDReadFIFO();
		}
	}
	else
	{
		// Ensure FIFO has data.
		if (hddXfer && hddRead)
		{
			HDDWriteFIFO();
		}

		if (iopXfer)
		{
			// Perform DMA to IOP.
			IOPReadFIFO();

			// Refill FIFO after DMA.
			// Need to recheck dmaReady incase prior
			// HDDWriteFIFO competed the transfer from HDD
			if (hddXfer && hddRead && dev9.ata->dmaReady)
			{
				HDDWriteFIFO();
			}
		}
	}

	FIFOIntr();
}

u16 SpeedRead(u32 addr, int width)
{