lkml.org 
[lkml]   [2011]   [Jan]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] ARM: vfp: Fix up exception location in Thumb mode
On Sun, Jan 16, 2011 at 11:49:21AM +0000, Catalin Marinas wrote:
> On Saturday, 15 January 2011, Russell King - ARM Linux
> <linux@arm.linux.org.uk> wrote:
> > It's a reveq, so I thought we should cover all the instructions with
> > an 'eq' conditional for thumb.
>
> If the it instruction doesn't cover all instructions, gas generates
> some more its. But in this case, for little endian, the it instruction
> covers more since reveq isn't included and having the beq not last in
> the block I think is unpredictable. If you really want to optimise the
> big endian case not to have an additional it generated by gas, you can
> write ittt so that beq is included with little endian but not with big
> endian. I wouldn't bother much for an extra it anyway.

I think the itttt is correct. Unless you wish to illustrate why you
think it's wrong by pasting the code and showing why you think the
beq isn't the last instruction...

> >         tst     r3, #PSR_T_BIT
> >         subeq   r4, r2, #4
> > 1:      ldreqt  r0, [r4]
> >         reveq   r0, r0
> >         beq     call_fpe
>
> You can have the T bit set but the instruction a 32-bit Thumb in which
> case r2 is in the middle of such instruction rather than the next.
> Unless you only refer to the ARM mode, in which case the comment is
> fine.

So? I'm confused why you're making a mountain out of apparantly
nothing.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2011-01-23 16:55    [W:0.090 / U:38.136 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site