Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!husc6!cmcl2!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: Reason for using BCD arithmetic
Message-ID: <8737@smoke.BRL.MIL>
Date: 23 Oct 88 00:40:37 GMT
References: <8810211335.AA19348@ucbvax.Berkeley.EDU>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 11

In article <8810211335.AA19348@ucbvax.Berkeley.EDU> BBUXEIPD@UIAMVS.BITNET (Robert Pearson) writes:
>     You are quite correct that BCD arithmetic has 'roundoff error', as all
>'floating point' representations will have 'roundoff error' if the 'mantissa'
>is exceeded.

That is incorrect.  Not all so-called "floating point" schemes have fixed
significand size, and some (including those using variable-length BCD
strings) are able to represent results of arithmetic operations exactly.
A BCD-based one will have problems with division, but that is not usually
commercially significant (whereas the errors introduced by use of normal
flotaing-point hardware is).