UNIX 6th Ed. - /usr/sys/dmr/cat.c

   1: #
   2: /*
   3:  */
   4: 
   5: /*
   6:  * GP DR11C driver used for C/A/T
   7:  */
   8: 
   9: #include "../param.h"
  10: #include "../user.h"
  11: #include "../tty.h"
  12: 
  13: #define CATADDR 0167750
  14: #define PCAT    9
  15: #define CATHIWAT    60
  16: #define CATLOWAT    15
  17: 
  18: struct {
  19:     int catlock;
  20:     struct  clist   oq;
  21: } cat;
  22: 
  23: struct {
  24:     int catcsr;
  25:     int catbuf;
  26: };
  27: 
  28: ctopen(dev)
  29: {
  30:     if (cat.catlock==0) {
  31:         cat.catlock++;
  32:         CATADDR->catcsr =| IENABLE;
  33:     } else
  34:         u.u_error = ENXIO;
  35: }
  36: 
  37: ctclose()
  38: {
  39:     cat.catlock = 0;
  40: }
  41: 
  42: ctwrite(dev)
  43: {
  44:     register c;
  45:     extern lbolt;
  46: 
  47:     while ((c=cpass()) >= 0) {
  48:         spl5();
  49:         while (cat.oq.c_cc > CATHIWAT)
  50:             sleep(&cat.oq, PCAT);
  51:         while (putc(c, &cat.oq) < 0)
  52:             sleep(&lbolt, PCAT);
  53:         catintr();
  54:         spl0();
  55:     }
  56: }
  57: 
  58: catintr()
  59: {
  60:     register int c;
  61: 
  62:     if (CATADDR->catcsr&DONE && (c=getc(&cat.oq))>=0) {
  63:         CATADDR->catbuf = c;
  64:         if (cat.oq.c_cc==0 || cat.oq.c_cc==CATLOWAT)
  65:             wakeup(&cat.oq);
  66:     } else {
  67:         if (cat.catlock==0)
  68:             CATADDR->catcsr = 0;
  69:     }
  70: }

Defined functions

Defined macros