2.9BSD - /usr/src/lib/ape/gcd.c

   1: #ifndef lint
   2: static char sccs_id[] = "@(#)gcd.c	2.2	8/13/82";
   3: #endif lint
   4: #include <ape.h>
   5: gcd(a,b,c)
   6: MINT *a,*b,*c; /* c = gcd of a and b; computed by
   7: 		the Euclidean algorithm */
   8: {   MINT x,y,z,w;
   9:     x.len=y.len=z.len=w.len=0;
  10: 
  11:     move(a,&x);
  12:     move(b,&y);
  13: 
  14:     while(y.len!=0)
  15:     {   mdiv(&x,&y,&w,&z);
  16:         move(&y,&x);
  17:         move(&z,&y);
  18:     }
  19:     move(&x,c);
  20:     xfree(&x);
  21:     xfree(&y);
  22:     xfree(&z);
  23:     xfree(&w);
  24:     return;
  25: }
  26: 
  27: /* Until I know what this ought to do I'm leaving it out
  28: 
  29: invert(a, b, c)
  30: MINT *a, *b, *c;
  31: {	MINT x, y, z, w, Anew, Aold;
  32: 	int i = 0;
  33: 	x.len = y.len = z.len = w.len = Aold.len = 0;
  34: 	Anew.len = 1;
  35: 	Anew.val = xalloc(1,"invert");
  36: 	*Anew.val = 1;
  37: 	move(b, &x);
  38: 	move(a, &y);
  39: 	while(y.len != 0)
  40: 	{	mdiv(&x, &y, &w, &z);
  41: 		move(&Anew, &x);
  42: 		mult(&w, &Anew, &Anew);
  43: 		madd(&Anew, &Aold, &Anew);
  44: 		move(&x, &Aold);
  45: 		move(&y, &x);
  46: 		move(&z, &y);
  47: 		i++;
  48: 	}
  49: 	move(&Aold, c);
  50: 	if( (i&01) == 0) msub(b, c, c);
  51: 	xfree(&x);
  52: 	xfree(&y);
  53: 	xfree(&z);
  54: 	xfree(&w);
  55: 	xfree(&Aold);
  56: 	xfree(&Anew);
  57: }
  58: 	I'm adding this, which is sort of an ``invert''! */
  59: 
  60: reciprocal(a,n,b)
  61: PMINT a,b;      /* b = 10^n / a -- i.e., gives n decimal places
  62: 			 * of 1/a. */
  63: int n;
  64: {
  65:     PMINT x;
  66: 
  67:     new(&x);
  68:     lpow(10,(long)n,x);
  69:     mdiv(x,a,b,x);
  70:     afree(x);
  71:     return;
  72: }

Defined functions

Defined variables