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Date: Sat, 26 May 2012 20:51:22 -0400
From: Tim Prince <n8tm AT aol DOT com>
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Subject: Re: Is the Latest Release of Cygwin supported on Windows Server 8/2012
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On 05/26/2012 07:40 PM, Linda Walsh wrote:
>
>
>     Every time you fetch a word or instruction that is not 8-byte 
> aligned,
> you force a fatal (but caught by the processor and/or OS) signal for 
> unaligned
> data.  That forces execution out of the pipeline (though not likely 
> out of
> cache, sadly, due to frequency of occurrence).  That's not counting 
> the extra
> cycles to fetch the rest of the data.  On some machines that can 
> easily amount
> to several dozen instructions worth.
>
There have been compilers for 32-bit Windows for 20 years which gave 
8-byte alignments by default.  cygwin changed the default configure 
parameter in binutils so as to support alignment about 8 years ago.  It 
was tolerable to some before then as it matters only for 64-bit and 
larger objects (doubles, and SSE, after that was introduced).  The 
characteristics of the worst compiler (with respect to alignment) 
available outside of cygwin don't have a bearing on this list.
If the powers that be have decided that 64-bit mode should be supported 
on cygwin setup.exe only by mingw cross compilers, I'll accept that.

-- 
Tim Prince


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