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Re: bitrotate
From: |
Paolo Bonzini |
Subject: |
Re: bitrotate |
Date: |
Mon, 01 Sep 2008 09:43:01 +0200 |
User-agent: |
Thunderbird 2.0.0.16 (Macintosh/20080707) |
> I suspect the rotation part is the sarl+sall and or. Either we could
> experiment with changing the code, or we could try to make gcc detect
> that this code actually is a rotate... Possibly gcc already does that
> right thing, with today's CPU architectures it can be difficult to know
> which ops are the most efficient choice.
I don't know, GCC already has plenty of rotate-detection code. It might
be that for 16-bit it does not like to give a rotate to your machine.
Usually, trying with -mtune=i386 is a way to see if it has taken its
decision based on the hardware.
Paolo
- Re: bitrotate, Simon Josefsson, 2008/09/01
- Re: bitrotate,
Paolo Bonzini <=
- Re: bitrotate, Bruno Haible, 2008/09/01
- Re: bitrotate, Simon Josefsson, 2008/09/01
- Re: bitrotate, Simon Josefsson, 2008/09/01
- Re: bitrotate, Ben Pfaff, 2008/09/01
- Re: bitrotate, Bruno Haible, 2008/09/01
- Re: bitrotate, Simon Josefsson, 2008/09/02
- Re: bitrotate, Eric Blake, 2008/09/02
- Re: bitrotate, Simon Josefsson, 2008/09/02