util/int/text.c

   1 /*
   2         Manipulating the Program Counter
   3 */
   4
   5 /* $Id: text.c,v 2.3 1994/06/24 10:49:22 ceriel Exp $ */
   6
   7 #include        <em_abs.h>
   8 #include        "global.h"
   9 #include        "alloc.h"
  10 #include        "trap.h"
  11 #include        "text.h"
  12 #include        "read.h"
  13 #include        "proctab.h"
  14 #include        "warn.h"
  15
  16 init_text() {
  17         DB = i2p(NTEXT);                /* set Descriptor Base */
  18         NProc = NPROC;                  /* set Number of Proc. Descriptors */
  19         PI = -1;                        /* initialize Procedure Identifier */
  20         PC = 0;                         /* initialize Program Counter */
  21
  22         text = Malloc((size)p2i(DB), "text space");
  23 }
  24
  25
  26 /************************************************************************
  27  *      Program Counter division                                        *
  28  ************************************************************************
  29  *                                                                      *
  30  *      newPC(p)        - check and adjust PC.                          *
  31  *                                                                      *
  32  ************************************************************************/
  33
  34 newPC(p)
  35         register ptr p;
  36 {
  37         register struct proc *pr = &proctab[PI];
  38
  39         if (p >= DB) {
  40                 wtrap(WPCOVFL, EBADPC);
  41         }
  42         if (p < pr->pr_ep || p >= pr->pr_ff) {
  43                 wtrap(WPCPROC, EBADPC);
  44         }
  45         PC = p;
  46 }
  47