Re: [PATCH] Handle sparc compare-and-branch

[David Miller <davem@davemloft.net>]

From: Mark Kettenis <mark.kettenis@xs4all.nl>
Date: Sat, 21 Apr 2012 12:11:34 +0200 (CEST)

>> Date: Fri, 20 Apr 2012 20:34:08 -0400 (EDT)
>> From: David Miller <davem@davemloft.net>
>> 
>> SPARC-T4 adds a "compare and branch" instruction which fuses
>> a compare and a branch instruction into one.  The branch
>> is non-delayed, there are no anulling facilities, and the
>> displacement is 10-bits.
> 
> Is this new instruction documented anywhere?

Not publicly at the current time, but such documents will be available
soon.

I've posted binutils patches the other day if you're interested in the
opcodes :-)

>> This also corrects the existing bit test for Branch on
>> Integer Register.  The distinguising characteristic between
>> Branch on Integer Register and Compare-and-Branch is bit
>> 28.  The existing code was checking bit 24 for zero, but
>> that's pointless because bit 24 is already covered by
>> the "X_OP2 (insn) == 3" test.
>> 
>> Ok to commit?
> 
> Makes sense to me, so please go ahead.

Thanks.