int postime(int dist) /* distance in sectors */
{
    int i, add = 0;
    int np = sizeof(postime_data) / sizeof(postime_data[0]) - 1;

    if (dist < 0) dist = -dist;
    if (dist <= postime_data[0].dist) return postime_data[0].time;
    if (dist > postime_data[np].dist) return postime_data[np].time;

    for (i = 0; i < np; i++)
	if (dist <= postime_data[i+1].dist) {
	    return add +
		    (((quad_t)(postime_data[i+1].dist-dist)) * postime_data[i].time +
		     ((quad_t)(dist-postime_data[i].dist)) * postime_data[i+1].time) /
		    (postime_data[i+1].dist - postime_data[i].dist);
	}
    printf("boom!\n");
    return 0;
}