4.3BSD - /usr/src/ucb/lisp/franz/68k/calqhat.c

   1: /* Copyright (c) 1982, Regents, University of California */
   2: struct vl   { long high; long low; };
   3: calqhat(uj,v1)
   4: register long *uj, *v1;
   5: {
   6:     struct vl work1, work2;
   7:     register handy, handy2;
   8:     register qhat, rhat;
   9:     char err;
  10:     if(*v1==*uj) {
  11:         /* set qhat to b-1
  12: 		 * rhat is easily calculated since if we substite b-1
  13: 		 * for qhat in the formula below, one gets (u[j+1] + v[1])
  14: 		 */
  15:          qhat = 0x3fffffff;
  16:          rhat = uj[1] + *v1;
  17:     } else {
  18:         /* work1 = u[j]b + u[j+1]; */
  19:         handy2 = uj[1];
  20:         handy = *uj;
  21:         if(handy & 1) handy2 |= 0x40000000;
  22:         if(handy & 2) handy2 |= 0x80000000;
  23:         handy >>= 2;
  24:         work1.low = handy2; work1.high = handy;
  25:         qhat = ediv(&work1,*v1,&err);
  26:         /* rhat = work1 - qhat*v[1]; */
  27:         rhat = work1.high;
  28:     }
  29: again:
  30:     /* check if v[2]*qhat > rhat*b+u[j+2] */
  31:     emul(qhat,v1[1],0,&work1);
  32:     /* work2 = rhat*b+u[j+2]; */
  33:     { handy2 = uj[2]; handy = rhat;
  34:     if(handy & 1) handy2 |= 0x40000000;
  35:     if(handy & 2) handy2 |= 0x80000000;
  36:     handy >>= 2; work2.low = handy2; work2.high = handy; }
  37:     vlsub(&work1,&work2);
  38:     if(work1.high <= 0) return(qhat);
  39:     qhat--; rhat += *v1;
  40:     goto again;
  41: }

Defined functions

Defined struct's