From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 In-Reply-To: References: <1411330.QJAbfBr5F9@blitz> Date: Sat, 5 May 2012 17:06:39 -0400 Message-ID: From: Comeau At9Fans To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Content-Type: multipart/alternative; boundary=14dae939986dc119d304bf50697a Subject: Re: [9fans] integer width on AMD64 (was: Re: AMD64 system) Topicbox-Message-UUID: 842ed588-ead7-11e9-9d60-3106f5b1d025 --14dae939986dc119d304bf50697a Content-Type: text/plain; charset=ISO-8859-1 On Sat, May 5, 2012 at 1:48 PM, Charles Forsyth wrote: > if it's performance you're worried about, for programs that don't care > about width, i'd expect 32 bits at least > to match performance with 64 bits (if there's a measurable difference). > for one thing, cache lines will contain > more values, and several will be fetched at once when cache lines are > filled. > And for programs that do care about this, C99 provides things such as int_fast64_t (which IIRC 8c et al does not currently support). In a way, expecting something out of 'int' is sloppy, despite it's wide use. -- Greg Comeau / 4.3.10.1 with C++0xisms now in beta! Comeau C/C++ ONLINE ==> http://www.comeaucomputing.com/tryitout World Class Compilers: Breathtaking C++, Amazing C99, Fabulous C90. Comeau C/C++ with Dinkumware's Libraries... Have you tried it? --14dae939986dc119d304bf50697a Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On Sat, May 5, 2012 at 1:48 PM, Charles Forsyth <charles.forsyth@g= mail.com> wrote:
if it's performance you're worried about, for programs that do= n't care about width, i'd expect 32 bits at least
to matc= h performance with 64 bits (if there's a measurable difference). for on= e thing, cache lines will contain
more values, and several will be fetched at once when cache lines are = filled.

And for programs that do = care about this, C99 provides things such as int_fast64_t (which IIRC 8c et= al does not currently support). =A0In a way, expecting something out of &#= 39;int' is sloppy, despite it's wide use.

--
Greg Comeau / 4.3.10.1 with C++0xisms now in beta!
Comeau C/C++ ONLINE =3D=3D> =A0 =A0 http://www.comeaucomputing.com/tr= yitout
World Class Compilers: =A0Breathtaking C++, Amazing C99, Fabulous C90.=
Comeau C/C++ with Dinkumware's Libraries... Have you tried i= t?

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