BSD 4 release

[unix-history] / usr / src / cmd / lisp / pbignum.c

static char *sccsid = "@(#)pbignum.c    34.1 10/3/80";

#include "global.h"

pbignum(current, useport)
register lispval current;
register FILE *useport;
{
       int  *top, *bot, *work, negflag = 0, *sp(), *alloca();
       register int *digitp, *binp;
       register lispval last;

       /* copy bignum onto stack */
       top = sp() - 1;
       do {
               stack(current->s.I);
       } while(current = current->s.CDR);

       bot = sp();
       if (top==bot) {
               fprintf(useport,"%d",*bot);
               return;
       }

       /* save space for printed digits*/
       work = alloca((top-bot)*2*sizeof(int));
       if( *bot < 0) {
               negflag = 1;
               dsneg(top,bot);
       }

       /* figure out nine digits at a time by destructive division*/
       for(digitp = work; bot <= top; digitp++) {
               *digitp = dodiv(top,bot);
               if(*bot==0) bot += 1;
       }
       
       /* print them out */

       if(negflag) putc('-',useport);
       fprintf(useport,"%d",*--digitp);
       while ( digitp > work) fprintf(useport,"%09d",*--digitp);
}