4.3BSD - /usr/src/usr.lib/libmp/pow.c

   1: /*
   2:  * Copyright (c) 1980 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  */
   6: 
   7: #ifndef lint
   8: static char sccsid[] = "@(#)pow.c	5.1 (Berkeley) 4/30/85";
   9: #endif not lint
  10: 
  11: #include <mp.h>
  12: pow(a,b,c,d) MINT *a,*b,*c,*d;
  13: {   int i,j,n;
  14:     MINT x,y;
  15:     x.len=y.len=0;
  16:     xfree(d);
  17:     d->len=1;
  18:     d->val=xalloc(1,"pow");
  19:     *d->val=1;
  20:     for(j=0;j<b->len;j++)
  21:     {   n=b->val[b->len-j-1];
  22:         for(i=0;i<15;i++)
  23:         {   mult(d,d,&x);
  24:             mdiv(&x,c,&y,d);
  25:             if((n=n<<1)&0100000)
  26:             {   mult(a,d,&x);
  27:                 mdiv(&x,c,&y,d);
  28:             }
  29:         }
  30:     }
  31:     xfree(&x);
  32:     xfree(&y);
  33:     return;
  34: }
  35: rpow(a,n,b) MINT *a,*b;
  36: {   MINT x,y;
  37:     int i;
  38:     x.len=1;
  39:     x.val=xalloc(1,"rpow");
  40:     *x.val=n;
  41:     y.len=n*a->len+4;
  42:     y.val=xalloc(y.len,"rpow2");
  43:     for(i=0;i<y.len;i++) y.val[i]=0;
  44:     y.val[y.len-1]=010000;
  45:     xfree(b);
  46:     pow(a,&x,&y,b);
  47:     xfree(&x);
  48:     xfree(&y);
  49:     return;
  50: }

Defined functions

Defined variables