Newsgroups: comp.lang.c++
Path: utzoo!henry
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Add-with-carry operator
Message-ID: <1991Feb7.163024.7601@zoo.toronto.edu>
Organization: U of Toronto Zoology
References: <1991Feb3.202530.14874@julius.cs.uiuc.edu> <3189@ux.acs.umn.edu> <1991Feb6.210332.12826@julius.cs.uiuc.edu>
Date: Thu, 7 Feb 1991 16:30:24 GMT

In article <1991Feb6.210332.12826@julius.cs.uiuc.edu> zweig@cs.uiuc.edu writes:
>	WHY SHOULD I HAVE TO WRITE CODE THAT PERFORMS OPERATIONS THAT ARE
>	UNNECESSARY ON EVERY MICROPROCESSOR PRODUCED WITHIN THE LAST 10
>	YEARS?

The fast answer is "because there are machines on which they are necessary".
Standards committees hesitate to require features that are flat-out
unimplementable on some machines, like a carry bit.  Admittedly, such
machines are not common, but they do exist; my MSc thesis involved work
on one.

The right answer to such a requirement is probably a subroutine library
written in assembler.
-- 
"Maybe we should tell the truth?"      | Henry Spencer at U of Toronto Zoology
"Surely we aren't that desperate yet." |  henry@zoo.toronto.edu   utzoo!henry