UNIX 7th Ed. - /usr/src/libmp/msqrt.c

   1: #include <mp.h>
   2: msqrt(a,b,r) MINT *a,*b,*r;
   3: {   MINT x,junk,y;
   4:     int j;
   5:     x.len=junk.len=y.len=0;
   6:     if(a->len<0) fatal("msqrt: neg arg");
   7:     if(a->len==0)
   8:     {   b->len=0;
   9:         r->len=0;
  10:         return(0);
  11:     }
  12:     if(a->len%2==1) x.len=(1+a->len)/2;
  13:     else x.len=1+a->len/2;
  14:     x.val=xalloc(x.len,"msqrt");
  15:     for(j=0;j<x.len;x.val[j++]=0);
  16:     if(a->len%2==1) x.val[x.len-1]=0400;
  17:     else x.val[x.len-1]=1;
  18:     xfree(b);
  19:     xfree(r);
  20: loop:
  21:     mdiv(a,&x,&y,&junk);
  22:     xfree(&junk);
  23:     madd(&x,&y,&y);
  24:     sdiv(&y,2,&y,(short *)&j);
  25:     if(mcmp(&x,&y)>0)
  26:     {   xfree(&x);
  27:         move(&y,&x);
  28:         xfree(&y);
  29:         goto loop;
  30:     }
  31:     xfree(&y);
  32:     move(&x,b);
  33:     mult(&x,&x,&x);
  34:     msub(a,&x,r);
  35:     xfree(&x);
  36:     return(r->len);
  37: }

Defined functions