/*****************************************************************************************************
		Example code showing the DMA transfer from linkport 0 to internal memory and then a transfer
		from internal memory back out to link port 0.

******************************************************************************************************/
#define __NOUNDERSCORES__							// Depending on the compiler patch installed, the register names as defined in sysreg.h 
													// may now have two underscores prepended so that they do not restrict the namespace 
													// of user programs. If the old names are required as in this example(without the 
													// underscores prepended), 
													// define the preprocessor macro __NOUNDERSCORES__ before including sysreg.h.
													// Only required with compiler patch 6.1.7 or later

#include "sysreg.h"
#include "signal.h"
#include "stdio.h"

#define N 64										// Number of words to transfer

int dm data_rx_tx[N];								// Data to be received and transmitted back through link port

struct TCB {
	int *DI;										// index
	int DX;											// count and stride in x direction
	int DY;											// count and stride in y direction
	int DP;											// DMA control word
};

struct TCB TCB_temp;								// Temp structure for programming TCBs

__builtin_quad q;									// Temp quad for programming TCBs

void dma4_int();									// Prototype for interrupt service routine
void dma8_int();

void main(void)
{
	int i=0;	
		
	interrupt(SIGDMA4, dma4_int);					// Assign isr to DMA channel 4 (Link port 0 transmit)
	interrupt(SIGDMA8, dma8_int);					// Assign isr to DMA channel 8 (Link port 0 receive)
													
	TCB_temp.DI = data_rx_tx;						// index points to source buffer
	TCB_temp.DX = 4 | (N << 16);					// modify is 4 for quad-word transfers, count is N and must be shifted to upper half 
	TCB_temp.DY = 0;								// only a 1 dimension DMA
	TCB_temp.DP = 0x47000000;						// control word set for quad-word transfers to internal memory with interrupt enabled
	
	__builtin_sysreg_write(LCTL0, 0x000004DA);

	q = __builtin_compose_128((long long)TCB_temp.DI | (long long)TCB_temp.DX << 32, (long long)(TCB_temp.DY | (long long)TCB_temp.DP << 32));
	__builtin_sysreg_write4(DC8, q);				// program the TCBs

	while(1)										// Endless loop
		i=i-i;
}


/*********************************************************************************************************************************************/
/*	DMA8 Interrupt Service Routine ***********************************************************************************************************/
/*********************************************************************************************************************************************/
void dma8_int()										// ISR for DMA channel 8
{		
	interrupt(SIGDMA4, dma4_int);					// Assign isr to DMA channel 4
	
	TCB_temp.DI = data_rx_tx;						// index points to source buffer in external memory
	TCB_temp.DP = 0x47000000;						// control word set for quad-word transfers to internal memory with interrupt enabled

	q = __builtin_compose_128((long long)TCB_temp.DI | (long long)TCB_temp.DX << 32, (long long)(TCB_temp.DY | (long long)TCB_temp.DP << 32));
	__builtin_sysreg_write4(DC4, q);				// program the TCBs

return;
}

/*********************************************************************************************************************************************/
/*	DMA4 Interrupt Service Routine ***********************************************************************************************************/
/*********************************************************************************************************************************************/
void dma4_int()										// ISR for DMA channel 4
{		
	printf("\nLink port DMAs completed\n"); 
	return;
}