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Subject: Re: Arithmetic overflow checking
Date: Tue, 12 Jul 2011 13:20:15 -0700
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On 7/12/2011 12:38 PM, Patricia Shanahan wrote:

> It would not necessarily directly take time. It could be done in
> parallel with the stage that writes results back to register files, or
> bypasses them to other instructions.


A JO almost certainly would be executed in parallel with the ADD 
instruction.  Executing two instructions in parallel has been available 
on consumer CPU (x86) since about 1992.  It's two decade old technology. 
  Folks complaining about performance degradation due to overflow 
detection are frankly greatly out of date in their understanding of CPU 
architecture.