Date: Tue, 24 Jun 2003 08:51:31 -0300 From: "Daniel C. Sobral" <dcs@tcoip.com.br> To: Erik Trulsson <ertr1013@student.uu.se> Cc: freebsd-arch@freebsd.org Subject: Re: Message buffer and printf reentrancy patch Message-ID: <3EF83B43.3000100@tcoip.com.br> In-Reply-To: <20030615190209.GA75458@falcon.midgard.homeip.net> References: <200306151406.aa36218@salmon.maths.tcd.ie> <200306151826.h5FIPvM7046944@gw.catspoiler.org> <20030615190209.GA75458@falcon.midgard.homeip.net>
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Erik Trulsson wrote:
>
> With a C99 compiler it is always true. In C89 it was implementation
> defined if integer division rounded towards zero or towards
> negative-infinity. In C99 integer division always rounds towards zero.
> This combined with the fact that (a/b)*b + a%b == a is always true (for
> integer a,b and b!=0) means that (neg_int % pos_int <= 0 ) is always
> true in C99, while it wasn't always true in C89.
Heh. I recall when ANS Forth was being discussed that people found it
silly all the discussion around whether signed integer division was
symmetric or floored, when even C didn't bother with it. :-)
(And, if you are interested in such things, the problem was that
Forth-79 was symmetric, Forth-83 was floored (or vice versa -- I don't
know); the solution was to leave / as implementation defined and
creating two new operators: one symmetric and one floored. :)
--
Daniel C. Sobral (8-DCS)
Gerencia de Operacoes
Divisao de Comunicacao de Dados
Coordenacao de Seguranca
VIVO Centro Oeste Norte
Fones: 55-61-313-7654/Cel: 55-61-9618-0904
E-mail: Daniel.Capo@tco.net.br
Daniel.Sobral@tcoip.com.br
dcs@tcoip.com.br
Outros:
dcs@newsguy.com
dcs@freebsd.org
capo@notorious.bsdconspiracy.net
I finally got it all together ...
but I forgot where I put it.
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