source: soft/giet_vm/sort/main.c @ 278

///////////////////////////////////////////////////////////////////////////////
// File :
//      
//      main.c
//
// Date :
//      
//      November 2013
//
// Author :
//
//      Cesar Fuguet Tortolero <cesar.fuguet-tortolero@lip6.fr>
//
// Description :
//
//      Sort application using the GIET-VM OS. This application uses the
//      barrier routines to apply a sort algorithm in several stages.
//
//      Considerations :
//
//          - It supports up to 256 processors and the number of processors
//            must be a power of 2.
//
//          - If there is only one TTY available, this application uses a spin
//            lock to avoid several threads writting at the same time.
//
//          - This application must be executed on a cache coherent
//            architecture. Otherwise some modifications must be applied
//
//          - The processors executing this application must have a contiguous
//            processor id and the first processor must have id 0.
//
///////////////////////////////////////////////////////////////////////////////

#include "stdio.h"
#include "hard_config.h"
#include "barrier.h"

//////////////////////////////////////////////////////////////////////////
// The NTHREADS constant must be modified depending on the desired number of
// threads

#define NTHREADS        8
#define ARRAY_LENGTH    (NTHREADS * 128)
#define IPT             (ARRAY_LENGTH / NTHREADS) // ITEMS PER THREAD

////////////////////////////////////////////////////////////////////////////////
// Processors other than 0 display algorithm state
// The processor 0 always displays some information so this does not affect him 

#define VERBOSE         1

///////////////////////////////////////////////////////////////////////
// Define printf according to verbosity option and number of available
// TTY

#if (VERBOSE == 1)
#   define printf(...)     giet_tty_printf(__VA_ARGS__)
#   define puts(...)       giet_tty_puts(__VA_ARGS__)
#else       // VERBOSE == 0
#   define printf(...)
#   define puts(...)
#endif

#define task0_printf(...) if(thread_id == 0) giet_tty_printf(__VA_ARGS__)

#define exit    giet_exit
#define procid  giet_procid
#define rand    giet_rand

int array0[ARRAY_LENGTH];
int array1[ARRAY_LENGTH];

volatile int init_ok = 0;

void bubbleSort(
        int * array,
        unsigned int length,
        unsigned int init_pos);

void merge(
        int * array,
        int * result,
        int length,
        int init_pos_a,
        int init_pos_b,
        int init_pos_result);

///////////////////////////////////////////////////
// This application support at most 256 processors
// Number of barriers = log2(NTHREADS)

giet_barrier_t barrier[8];

__attribute__ ((constructor)) void sort()
{
    int thread_id = giet_thread_id();

    int * src_array;
    int * dst_array;
    int i;

    printf("[ Thread %d ] Initializing vector and barriers...\n\r", thread_id);

    ///////////////////////////
    // Barriers Initialization

    for (i = 0; i < __builtin_ctz(NTHREADS); i++)
    {
        barrier_init(&barrier[i], NTHREADS >> i);
    }

    ////////////////////////
    // Array Initialization

    for (i = IPT * thread_id; i < IPT * (thread_id + 1); i++)
    {
        array0[i] = rand();
    }

    ///////////////////////////////////
    // Parallel sort of array elements

    printf("[ Thread %d ] Stage 0: Processor Sorting...\n\r", thread_id);

    bubbleSort(array0, IPT, IPT * thread_id);

    printf("[ Thread %d ] Finishing Stage 0\n\r", thread_id);

    for (i = 0; i < __builtin_ctz(NTHREADS); i++)
    {
        asm volatile ("sync");
        barrier_wait(&barrier[i]);

        if((thread_id % (2 << i)) != 0)
        {
            printf("[ Thread %d ] Quits\n\r", thread_id);
            exit();
        }

        printf("[ Thread %d ] Stage %d: Starting...\n\r", thread_id, i+1);

        if((i % 2) == 0)
        {
            src_array = &array0[0];
            dst_array = &array1[0];
        }
        else
        {
            src_array = &array1[0];
            dst_array = &array0[0];
        }

        merge(src_array, dst_array
                , IPT << i
                , IPT * thread_id
                , IPT * (thread_id + (1 << i))
                , IPT * thread_id
                );

        printf("[ Thread %d ] Finishing Stage %d\n\r", thread_id, i + 1);
    }

    int success;
    int failure_index;

    //////////////////////////////
    // Verify the resulting array

    if(thread_id == 0)
    {
        success = 1;

        for(i=0; i<(ARRAY_LENGTH-1); i++)
        {
            if(dst_array[i] > dst_array[i+1])
            {

                success = 0;
                failure_index = i;
                break;
            }
        }

        if (success)
        {
            printf("[ Thread 0 ] Success!!\n\r");
        }
        else
        {
            printf("[ Thread 0 ] Failure!! Incorrect element: %d\n\r", failure_index);


            for(i=0; i<ARRAY_LENGTH; i++)
            {
                printf("array[%d] = %d\n", i, dst_array[i]);
            }
        }
    }

    exit();
}

void bubbleSort(
        int * array,
        unsigned int length,
        unsigned int init_pos)
{
    int i;
    int j;
    int aux;

    for(i = 0; i < length; i++)
    {
        for(j = init_pos; j < (init_pos + length - i - 1); j++)
        {
            if(array[j] > array[j + 1])
            {
                aux          = array[j + 1];
                array[j + 1] = array[j];
                array[j]     = aux;
            }
        }
    }
}

void merge(
        int * array,
        int * result,
        int length,
        int init_pos_a,
        int init_pos_b,
        int init_pos_result)
{
    int i;
    int j;
    int k;

    i = 0;
    j = 0;
    k = init_pos_result;

    while((i < length) || (j < length))
    {
        if((i < length) && (j < length))
        {
            if(array[init_pos_a + i] < array[init_pos_b + j])
            {
                result[k++] = array[init_pos_a + i];
                i++;
            }
            else
            {
                result[k++] = array[init_pos_b + j];
                j++;
            }
        }
        else if(i < length)
        {
            result[k++] = array[init_pos_a + i];
            i++;
        }
        else
        {
            result[k++] = array[init_pos_b + j];
            j++;
        }
    }
}

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*/