#include <stdio.h>
#include <rtems.h>
#include <rtems/error.h>
#include <time.h>

#define TERMINATOR_TURTLE 0x01
#define TERMINATOR_RABBIT 0x02

static rtems_id tid_turtle;
static rtems_id tid_rabbit;


static char shadow_reg_led = 0x00;
static char *reg_led = 0x9fff0003; 
static char *reg_sw  = 0x9fff0101;

static char turtle_led = 0x01;
static char rabbit_led = 0x01;

static rtems_id procMutex;


static rtems_task turtle(rtems_task_argument ignored)
{
    char sw;
    struct timespec req, rem;
    req.tv_sec  = 0;
    req.tv_nsec = (1./4.) * 1000000000L;

    printf(">>>> start turtle <<<<\n");

    for(;;) {
        if(turtle_led == 0x80) turtle_led = 0x01;
        else turtle_led <<= 1;

        rtems_semaphore_obtain(procMutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT);
        shadow_reg_led = turtle_led | rabbit_led; 
        output_byte(reg_led, shadow_reg_led);
        rtems_semaphore_release(procMutex);

        sw = input_byte(reg_sw);
        if(!(sw & TERMINATOR_TURTLE)) break;
        
        nanosleep(&req, &rem);
    }

    printf(">>>> finish turtle <<<<\n");

    rtems_task_delete(RTEMS_SELF);

}

static rtems_task rabbit(rtems_task_argument ignored)
{
    char sw;
    struct timespec req, rem;
    req.tv_sec  = 0;
    req.tv_nsec = (1./16.) * 1000000000L;

    printf(">>>> start rabbit <<<<\n");

    for(;;) {
        if(rabbit_led == 0x80) rabbit_led = 0x01;
        else rabbit_led <<= 1;

        rtems_semaphore_obtain(procMutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT);
        shadow_reg_led = turtle_led | rabbit_led;
        output_byte(reg_led, shadow_reg_led);
        rtems_semaphore_release(procMutex);

        sw = input_byte(reg_sw);
        if(!(sw & TERMINATOR_RABBIT)) break;

        nanosleep(&req, &rem);
    }

    printf(">>>> finish rabbit <<<<\n");

    rtems_task_delete(RTEMS_SELF);

}



rtems_task tr_init(rtems_task_argument ignored)
{
    printf(">>>> Init for turtle and rabbit <<<<\n");

    rtems_semaphore_create(rtems_build_name('M', 'U', 'T', 'X'),
                           1,
                           RTEMS_FIFO | RTEMS_BINARY_SEMAPHORE | RTEMS_INHERIT_PRIORITY |
                           RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL,
                           0,
                           &procMutex);

    rtems_task_create(rtems_build_name('T', 'U', 'R', 'T'),
                      200,
                      16*1024,
                      RTEMS_PREEMPT | RTEMS_TIMESLICE | RTEMS_NO_ASR | RTEMS_INTERRUPT_LEVEL(0),
                      RTEMS_FLOATING_POINT | RTEMS_LOCAL, 
                      &tid_turtle);
    rtems_task_start(tid_turtle, turtle, 0);

    rtems_task_create(rtems_build_name('R', 'A', 'B', 'T'),
                      200,
                      16*1024,
                      RTEMS_PREEMPT | RTEMS_TIMESLICE | RTEMS_NO_ASR | RTEMS_INTERRUPT_LEVEL(0),
                      RTEMS_FLOATING_POINT | RTEMS_LOCAL,
                      &tid_rabbit);
    rtems_task_start(tid_rabbit, rabbit, 0);



    printf(">>> Finish Init <<<<\n");
}