I tend to use MVCL like Tony does. The reason that I tend to not like doing
a EX of an MVC is because the MVC needs to be out-of-line. (and is the MVC
in the i-cache or the d-cache?) Also, this requires a base register to
address the area containing the MVC. Which is generally not a problem,
because I would guess that the MVC would be in the "constants" area of the
program. But that moves the MVC far away from the EX instruction. Unless
you use LOCTR a lot to section up the program. Which can lead to novice
programmers getting confused. Yes, I know about the "new" EXRL to avoid the
need of a base register.


On Tue, May 20, 2014 at 10:44 PM, Robin Vowels <[email protected]> wrote:

> From: "Tony Harminc" <[email protected]>
> Sent: Friday, May 16, 2014 8:44 AM
>
>
>  I use MVCL a lot even for very small moves where the length is not
>> known at assembly time. But I know my environment and its performance
>> requirements, and often judge the relative elegance, generality, and
>> programmer-readability of such an instruction to override what small
>> performance gain there might be to multipathing and/or loops.
>>
>
> Sounds like overkill.
> MVC with EX would be simpler.
>
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