src/systemc/tests/systemc/misc/synth/synth-1.0/gcd/gcd.cpp

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  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  implied.  See the License for the specific language governing
  permissions and limitations under the License.

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/*****************************************************************************

  gcd.cpp -- 

  Original Author: Martin Janssen, Synopsys, Inc., 2002-02-15

 *****************************************************************************/

/*****************************************************************************

  MODIFICATION LOG - modifiers, enter your name, affiliation, date and
  changes you are making here.

      Name, Affiliation, Date:
  Description of Modification:

 *****************************************************************************/

#include "systemc.h"

struct gcd_cc : public sc_module {
    sc_in_clk        clk;
    sc_in<bool>      reset;
    sc_in<unsigned>  a;
    sc_in<unsigned>  b;
    sc_out<unsigned> c;
    sc_out<bool>     ready;

    void gcd_compute();

    SC_HAS_PROCESS( gcd_cc );

    gcd_cc( sc_module_name name )
    {
        SC_CTHREAD( gcd_compute, clk.pos() );
        reset_signal_is(reset,true);
    }
};

void
gcd_cc::gcd_compute()
{
    unsigned tmp_a = 0;
    wait();         // Note that this wait() is required, otherwise,
                    // the reset is wrong!  This is a problem with BC,
                    // not our frontend.

    while (true) {
        unsigned tmp_b;

        c = tmp_a;
        ready = true;
        wait();

        tmp_a = a;
        tmp_b = b;
        ready = false;
        wait();

        while (tmp_b != 0) {

            unsigned tmp_c = tmp_a;
            tmp_a = tmp_b;
            wait();

            while (tmp_c >= tmp_b) {
                tmp_c = tmp_c - tmp_b;
                wait();
            }

            tmp_b = tmp_c;
            wait();
        }
    }
}

static int numbers[] = { 49597, 41218, 20635, 40894, 16767, 17233, 36246, 28171, 60879, 49566, 10971, 24107, 30561, 49648, 50031, 12559, 23787, 35674, 43320, 37558, 840, 18689, 62466, 6308, 46271, 49801, 43433, 22683, 35494, 35259, 29020, 19555, 10941, 49656, 60450, 27709, 1353, 31160, 55880, 62232, 15190, 1315, 20803, 45751, 50963, 5298, 58311, 9215, 2378 };
static unsigned numbers_index = 0;

struct testbench : public sc_module {
    sc_in_clk          clk;
    sc_inout<bool>     reset;
    sc_in<bool>        ready;
    sc_inout<unsigned> a;
    sc_inout<unsigned> b;
    sc_in<unsigned>    c;

    void reset_gen();
    void stimu_gen();
    void display();

    SC_HAS_PROCESS( testbench );

    testbench( sc_module_name name )
    {
        SC_CTHREAD( reset_gen, clk.pos() );
        SC_CTHREAD( stimu_gen, clk.pos() );
        SC_METHOD( display );
        sensitive << ready;
    }
};

void
testbench::reset_gen()
{
    reset = 0;
    wait();
    reset = 1;
    wait();
    wait();
    reset = 0;
    wait();
    /* die */
}

void
testbench::stimu_gen()
{
    while (true) {
        do { wait(); } while (ready == 0);
        a = (unsigned) numbers[numbers_index++ % (sizeof(numbers)/sizeof(numbers[0]))];
        b = (unsigned) numbers[(numbers_index*numbers_index) % (sizeof(numbers)/sizeof(numbers[0]))];
        numbers_index++;
    }
}

void
testbench::display()
{
    if (ready) {
        cout << "reset = " << reset << " ready = " << ready
             << " a = " << a << " b = " << b << " c = " << c << endl;
    }
}

int sc_main(int argc, char* argv[] )
{
    sc_signal<unsigned> a("a"), b("b"), c("c");
    sc_clock            clk("clk", 20, SC_NS);
    sc_signal<bool>     reset("reset"), ready("ready");

    a = 0;
    b = 0;
    c = 0;
    reset = false;
    ready = false;

    gcd_cc gcd("gcd");
    gcd(clk, reset, a, b, c, ready);

    testbench tb("tb");
    tb(clk, reset, ready, a, b, c);

    sc_start(2000000, SC_NS);
    return 0;
}