Producing a simple multi-threaded CBE program

To produce a simple program for the CBE, you should follow the steps listed below (this example is included in the SDK in /opt/cell/sdk/src/tutorial/simple).

The project is called simple. For this example, the PPE code will be built in the project directory, instead of a ppu sub-directory.

Create a directory named simple.

In directory simple, create a file named Makefile using the following code:

########################################################################
#			Subdirectories
########################################################################

DIRS		:= 	spu

########################################################################
#                       Target
########################################################################

PROGRAM_ppu			:= 	simple

########################################################################
#                       Local Defines
########################################################################

IMPORTS         := spu/lib_simple_spu.a -lspe2 -lpthread
# imports the embedded simple_spu library
# allows consolidation of spu program into ppe binary

########################################################################
#			make.footer
########################################################################

# make.footer is in the top of the SDK
ifdef CELL_TOP
	include $(CELL_TOP)/buildutils/make.footer
else
	include ../../../../buildutils/make.footer
endif

In directory simple, create a file simple.c using the following code:

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <libspe2.h>
#include <pthread.h>

extern spe_program_handle_t simple_spu;

#define MAX_SPU_THREADS 	16


void *ppu_pthread_function(void *arg) {
	spe_context_ptr_t ctx;
	unsigned int entry = SPE_DEFAULT_ENTRY;
	
	ctx = *((spe_context_ptr_t *)arg);
	if (spe_context_run(ctx,&entry, 0, NULL, NULL, NULL) < 0) {
		perror ("Failed running context");
		exit (1);
	}
	pthread_exit(NULL);
}


int main()
{
	int i,spu_threads;
	spe_context_ptr_t ctxs[MAX_SPU_THREADS];
	pthread_t threads[MAX_SPU_THREADS];

/* Determine the number of SPE threads to create */
spu_threads = spe_cpu_info_get(SPE_COUNT_USABLE_SPES, -1);
if (spu_threads > MAX_SPU_THREADS) spu_threads = MAX_SPU_THREADS;

	/* Create several SPE-threads to execute 'simple_spu' */
	for(i=0; i<spu_threads; i++) {
		/* Create context */
		if ((ctxs[i] = spe_context_create (0, NULL)) == NULL) {
			perror ("Failed creating context");
			exit (1);
		}
		/* Load program into context */
		if (spe_program_load (ctxs[i],&simple_spu)) {
			perror ("Failed loading program");
			exit (1);
		}
			/* Create thread for each SPE context */
    		if (pthread_create (&threads[i], NULL,&ppu_pthread_function,&ctxs[i]))  {
			perror ("Failed creating thread");
			exit (1);
  		}
	
	/* Wait for SPU-thread to complete execution. */
	for (i=0; i<spu_threads; i++) {
		if (pthread_join (threads[i], NULL)) {
			perror("Failed pthread_join");
			exit (1);
		}
	}
	
	printf("\nThe program has successfully executed.\n");
	
	return (0);
}

Create a directory named spu.

In the directory spu, create a file named Makefile using the following code:

#######################################################################
#			Target
########################################################################

PROGRAMS_spu 			:= simple_spu

# created embedded library
LIBRARY_embed			:= lib_simple_spu.a

########################################################################
#			make.footer
########################################################################

# make.footer is in the top of the SDK
ifdef CELL_TOP
	include $(CELL_TOP)/buildutils/make.footer
else
	include ../../../../../buildutils/make.footer
endif

In the same directory, create a file simple_spu.c using the following code:

#include <stdio.h>

int main(unsigned long long id)
{

	/* The first parameter of an spu program will always be the spe_id of the spe
	 * thread that issued it.
	 */
	printf("Hello Cell (0x%llx)\n", id);

	return 0;
}

Compile the program by entering the following command at the command line while in the simple directory:
```
make
```

This CBE program then creates SPE threads that output "Hello Cell (#)\n" to the systemsim output window, where # is the spe_id of the SPE thread that issued the print.