Date: Thu, 27 Aug 92 15:39:14 +0100
From: buers AT dg1 DOT chemie DOT uni-konstanz DOT de (Dieter Buerssner)
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Cc: dj AT ctron DOT com
Subject: doprnt bug and patch

doprnt can't print Infs and NaNs (not a number). If you try to print these
'numbers', go32 reports an Exception 14. This can be shown with the 
following program:

#include <stdio.h>
#include <math.h>
#include <stdlib.h>

main()
{
    printf(" 1.0/0.0  = % f\n-1.0/0.0  = % f\n", 1.0/0.0, -1.0/0.0);
    printf("asin(2.0) = % f\n", asin(2.0));
    exit(0);
} 

compile with
%gcc -o print print.c -lm

The following patch solves the problem. I suggest to apply this patch
after the patch sent by David M. Ronis (ronis AT ronis DOT chem DOT mcgill DOT ca).
(I think the patches are orthogonal, but I'm not sure).

Dieter

*** doprnt.org	Wed Aug 26 08:03:36 1992
--- doprnt.c	Thu Aug 27 07:13:06 1992
***************
*** 51,56 ****
--- 51,58 ----
  	    flags&SHORTINT ? (short basetype)va_arg(argp, int) : \
  	    va_arg(argp, int)
  
+ static int nan = 0; 
+ 
  #if 0
  #define	todigit(c)	((c) - '0')
  #define	tochar(n)	((n) + '0')
***************
*** 264,271 ****
  			*buf = NULL;
  			size = cvt(_double, prec, flags, &softsign, *fmt, buf,
  			    buf + sizeof(buf));
! 			if (softsign)
  				sign = '-';
  			t = *buf ? buf : buf + 1;
  			goto pforw;
  		case 'n':
--- 266,274 ----
  			*buf = NULL;
  			size = cvt(_double, prec, flags, &softsign, *fmt, buf,
  			    buf + sizeof(buf));
! 			if (softsign && !nan) /* it's not a number, so it doesn't need a sign */
  				sign = '-';
+ 			nan = 0;
  			t = *buf ? buf : buf + 1;
  			goto pforw;
  		case 'n':
***************
*** 452,457 ****
--- 455,464 ----
  	if (expcnt = isspecial(number, startp, signp))
  		return(expcnt);
  #endif
+ #ifdef __GO32__
+ 	if (expcnt = isspecial(number, startp))
+ 		return(expcnt);
+ #endif
  
  	dotrim = expcnt = gformat = 0;
  	fract = modf(number, &integer);
***************
*** 714,718 ****
--- 721,751 ----
  	else
  		(void)strcpy(bufp, "Inf");
  	return(3);
+ }
+ #endif
+ 
+ #ifdef __GO32__
+ isspecial(d, bufp)
+ 	double d;
+ 	char *bufp;
+ {
+     	register struct IEEEdp {
+         	unsigned manl:32;
+         	unsigned manh:20;
+         	unsigned exp:11;
+         	unsigned sign:1;
+ 	} *ip = (struct IEEEdp *)&d;
+ 
+ 	if (ip->exp != 0x7ff)
+ 		return(0);
+ 	if (ip->manh || ip->manl)
+     	{
+ 		strcpy(bufp, "NaN");
+         	nan = 1; /* kludge: we don't need the sign,  it's not nice
+ 		            but it should work */
+     	}
+ 	else
+ 		(void)strcpy(bufp, "Inf");
+     	return(3);
  }
  #endif