Messages in this thread |  | | | Date | Wed, 05 May 2010 10:30:18 +0300 | | From | Avi Kivity <> | | Subject | Re: [PATCH 1/2] x86: eliminate TS_XSAVE |
| |
On 05/04/2010 09:24 PM, H. Peter Anvin wrote: > > I would like to request one change, however. I would like to see the > alternatives code to be: > > movb $0,reg > movb $1,reg > > ... instead of using xor (which has to be padded with NOPs, which is of > course pointless since the slot is a fixed size.)
Right.
> I would suggest using > a byte-sized variable instead of a dword-size variable to save a few > bytes, too. >
I used a bool, and the code already compiles to a byte mov. Though it could be argued that a word instruction is better since it avoids a false dependency, and allows a preceding instruction that modifies %reg to be executed after the mov instruction.
> Once the jump label framework is integrated and has matured, I think we > should consider using it to save the mov/test/jump. >
IIRC that has an implied unlikely() which isn't suitable here?
Perhaps the immediate values patches.
-- error compiling committee.c: too many arguments to function
|  |