Date: Thu, 1 Nov 2007 01:39:11 +0300 From: Andrey Chernov <ache@nagual.pp.ru> To: Bruce Evans <brde@optusnet.com.au> Cc: cvs-src@FreeBSD.ORG, Christoph Mallon <christoph.mallon@gmx.de>, src-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/include _ctype.h Message-ID: <20071031223911.GC90994@nagual.pp.ru> In-Reply-To: <20071101024451.T4289@delplex.bde.org> References: <200710272232.l9RMWSbK072082@repoman.freebsd.org> <47264710.2000500@gmx.de> <20071101024451.T4289@delplex.bde.org>
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On Thu, Nov 01, 2007 at 03:23:56AM +1100, Bruce Evans wrote: > In fact, one of the cleanups/optimizations in rev.1.5 and 1.6 by ache > and me was to get rid of the mask. There was already a check for _c > < 0, so the mask cost even more. The top limit was 256 instead of > 128, so the point about 8bit immediates didn't apply, but I don't know > of any machines where the mask is faster (didn't look hard :-). OTOH, > _c is often a char or a u_char (it is declared as mumble_rune_t, but > the functions are inline so the compiler can see the original type. > If _c is u_char and u_char is uint8_t, then (_c < 0 || c >= 256) is > always false, so the compiler should generate no code for it. The top > limit of 256 was preferred so that this optimization is possible. A > top limit of 128 doesn't work so well. Please see the tests posted in this thread. -- http://ache.pp.ru/
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