Author: Gerd Isenberg
Date: 03:34:39 11/27/03
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On November 27, 2003 at 06:05:04, Daniel Clausen wrote: >On November 27, 2003 at 05:54:15, Gerd Isenberg wrote: > >>On November 27, 2003 at 05:33:17, Gian-Carlo Pascutto wrote: >> >>>On November 27, 2003 at 05:29:43, Gerd Isenberg wrote: >>> >>>>Be aware of the "signed extension" penalty if using signed 32-bit variables as >>>>array indicies, "long" is still 32-bit with msc but 64-bit in gcc: >>> >>>Ugh, that sucks! Of course all indexes are int here... >> >>Yes, the point is to avoid signed 32-bit int as index, due to the additional >>sign extension instruction. A signed 64-bit register variable as index register >>don't has this problem, but of course that should not imply to use explicitely >>64-bit long (gcc) or long long (gcc) or __int64 (msc) as index variables, unless >>your arrays are that huge ;-) >> >>Gerd >> >>> >>>-- >>>GCP > >So using unsigned 32-bit would be a good idea, right? > >Sargon Yes. I don't have such a box so far to try it by myself and to look at the generated code. But if i understand the amd-manual right that's the point. Gerd
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