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Re: Pentium4 branch hints


On Wed, Jun 06, 2001 at 06:53:38AM -0700, Doug Evans wrote:
> Alan Modra writes:
>  > Inspired by Jan Hubicka's recent patches to teach gcc about Pentium4
>  > branch hints, I decided to teach gas about them too.  Allows a line
>  > like:
>  > 
>  >         cs je dest
>  > 
>  > Of course, you can still do this sort of thing by
>  > 
>  >         cs
>  >         je dest
>  > 
>  > but if multiple prefixes are involved, it's better to give them to gas
>  > on one line.  gas will make sure they are emitted in the proper order.
> 
> While using `cs' is ok implementation-wise, at the assembly level ... blech.
> There's no mnemonic for remembering which is which.
> 
> Don't suppose you want to also accept something like "taken", "not-taken",
> as well (or some abbreviation thereof), and have those printed
> for disassembly, do you?

E.g. Sparc v9 style which could look like je,pt or je,pn (Predict Taken,
Predict Not taken) is pretty easy to write, or IA-64 style je.sptk or
je.spnt.

	Jakub


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