void* oldvbr;

unsigned short rwd;
unsigned short rwa;
unsigned int evt;
#pragma interrupt(gray_interrupt)

void gray_interrupt()
{
int evt = INTC.INTEVT;
if (evt != 0x400)
{
   Keyboard_TimerHandler();
   INTX.IPRD.WORD = 0x0000;
   return ;
}
TMU0.TCR.BIT.UNF = 0;
TMU.TSTR.BIT.STR0 = 0;
if(screen->which == 1)
    {
        draw_all(screen->DD1);
        screen->which = 2;
        TMU0.TCNT = TMU0.TCOR = screen->time1;
    } else {
        draw_all(screen->DD2);
        screen->which = 1;
        TMU0.TCNT = TMU0.TCOR = screen->time2;
    }
    TMU.TSTR.BIT.STR0 = 1;
}


void change_rw()
{
        rwa = INTC.IPRA.WORD;
    rwd = INTX.IPRD.WORD;
        INTC.IPRA.WORD = 0xf000;
    INTX.IPRD.WORD = 0x0000;
}
void reset_rw()
{
        INTC.IPRA.WORD = rwa;
    INTX.IPRD.WORD =rwd;
    Keyboard_TimerHandler();
}

int gray_init()
{    
         change_rw();

        screen = malloc(sizeof(Screen));
    if(!screen) return 0;
        contrast_gray();
    screen->VRAM1 = VRAM[0]; // partie à adapter à votre gestion du gris (voir aussi dans l'interruption)
    screen->VRAM2 = VRAM[1];
    screen->DD1 = VRAM[2];
    screen->DD2 = VRAM[3];
    screen->time1 = 3269;
    screen->time2 = 6987;
    screen->which = 1;
    oldvbr = _builtin_get_vbr();
    set_vbr((void *)((unsigned int)gray_interrupt - INT_OFFSET));

TMU0.TCR.WORD = 0x0022;
    TMU0.TCNT = TMU0.TCOR = screen->time1;
    TMU.TSTR.BIT.STR0 = 1;
    gray_was_used = 1;
    gray_clearBuffers();
        gray_refresh();
    return 1;
}


void gray_quit()
{

        TMU.TSTR.BIT.STR0 = 0;
        TMU0.TCR.WORD = 0x0000;
    TMU0.TCNT = TMU0.TCOR = 0xFFFFFFFF;
    set_vbr(oldvbr);
        reset_rw();
        gray_clearBuffers();
        gray_refresh();
        ML_display_vram(VRAM[0]);

    // code gestion du contraste
    free(screen);
}