Xref: utzoo comp.sources.games.bugs:22 rec.games.hack:2075
Path: utzoo!utgpu!water!watmath!clyde!rutgers!sri-spam!ames!sdcsvax!ucsdhub!hp-sdd!hplabs!sdcrdcf!sdcsmb!sea!eggert
From: eggert@sea.sm.unisys.com (Paul Eggert)
Newsgroups: comp.sources.games.bugs,rec.games.hack
Subject: nethack bug fix: 16-bit hosts can send you to heaven involuntarily
Message-ID: <4@sea.sm.unisys.com>
Date: 29 Jan 88 17:25:02 GMT
Reply-To: eggert@sea.sm.unisys.com (Paul Eggert)
Organization: Unisys Santa Monica
Lines: 36

A portability bug in nethack's rnd.c can affect adventurers on 16-bit hosts.
The bug caused an adventurer deep in the dungeon to be sent to heaven
involuntarily by a teleport trap.  His screams of disappointment caused me to
investigate the problem.  Here is a fix that makes integer overflow (and thus
heaven) less likely by a factor of 2^32 on such machines.

***************
*** 43,55 ****
  	return(tmp);
  }
  
! rnz(x)
! register x;
  {
!         register tmp = 1000;
  	tmp += rn2(1000);
  	tmp *= rne(4);
  	if (rn2(2)) { x *= tmp; x /= 1000; }
  	else { x *= 1000; x /= tmp; }
! 	return(x);
  }
--- 43,56 ----
  	return(tmp);
  }
  
! rnz(i)
! int i;
  {
! 	register long x = i;
! 	register long tmp = 1000;
  	tmp += rn2(1000);
  	tmp *= rne(4);
  	if (rn2(2)) { x *= tmp; x /= 1000; }
  	else { x *= 1000; x /= tmp; }
! 	return((int)x);
  }