מערכת ההפעלה XINU

/*------------------------------------------------------------------------

 * Format of each entry is:

 *

 * device number, device name,

 * init, open, close,

 * read, write, seek,

 * getc, putc, cntl,

 * port addr, device input vector, device output vector,

 * input interrupt routine, output interrupt routine,

 * device i/o block, minor device number

 *------------------------------------------------------------------------

 */

/* Device table declarations */

struct devsw  {                    /* device table entry             */

       int    dvnum;

       char   dvnam[8];

       int    (*dvinit)();

       int    (*dvopen)();

       int    (*dvclose)();

       int    (*dvread)();

       int    (*dvwrite)();

       int    (*dvseek)();

       int    (*dvgetc)();

       int    (*dvputc)();

       int    (*dvcntl)();

       int    dvport;

       int    dvivec;

       int    dvovec;

       int    (*dviint)();

       int    (*dvoint)();

       char   *dvioblk;

       int    dvminor;

       };

read(descrp, buff, count)

int descrp, count;

char *buff;

{

       struct devsw  *devptr;

       if (isbaddev(descrp) )

              return(SYSERR);

       devptr = &devtab[descrp];

       return(       (*devptr->dvread)(devptr,buff,count) );

}