[Qemu-devel] [4597] CRIS: Re-add the X flag to the tb flags, it allows for better code generation and is practially always cleared.

[Qemu-devel] [4597] CRIS: Re-add the X flag to the tb flags, it allows for better code generation and is practially always cleared.

[Edgar E. Iglesias]

Revision: 4597
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=4597
Author:   edgar_igl
Date:     2008-05-27 21:15:56 +0000 (Tue, 27 May 2008)

Log Message:
-----------
CRIS: Re-add the X flag to the tb flags, it allows for better code generation and is practially always cleared.

Modified Paths:
--------------
    trunk/cpu-exec.c

Modified: trunk/cpu-exec.c
===================================================================
--- trunk/cpu-exec.c	2008-05-27 21:13:40 UTC (rev 4596)
+++ trunk/cpu-exec.c	2008-05-27 21:15:56 UTC (rev 4597)
@@ -218,7 +218,7 @@
     cs_base = 0;
     pc = env->pc;
 #elif defined(TARGET_CRIS)
-    flags = env->pregs[PR_CCS] & U_FLAG;
+    flags = env->pregs[PR_CCS] & (U_FLAG | X_FLAG);
     flags |= env->dslot;
     cs_base = 0;
     pc = env->pc;

Re: [Qemu-devel] [4597] CRIS: Re-add the X flag to the tb flags, it allows for better code generation and is practially always cleared.

[Paul Brook]

On Tuesday 27 May 2008, Edgar E. Iglesias wrote:
> Revision: 4597
>           http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=4597
> Author:   edgar_igl
> Date:     2008-05-27 21:15:56 +0000 (Tue, 27 May 2008)
>
> Log Message:
> -----------
> CRIS: Re-add the X flag to the tb flags, it allows for better code
> generation and is practially always cleared.

Are you sure this is safe? It means you shouldn't do TB chaining from any 
block that modifies the X flag, and I don't see any code for that.

Paul

Re: [Qemu-devel] [4597] CRIS: Re-add the X flag to the tb flags, it allows for better code generation and is practially always cleared.

[Edgar E. Iglesias]

On Tue, May 27, 2008 at 11:30:02PM +0100, Paul Brook wrote:
> On Tuesday 27 May 2008, Edgar E. Iglesias wrote:
> > Revision: 4597
> >           http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=4597
> > Author:   edgar_igl
> > Date:     2008-05-27 21:15:56 +0000 (Tue, 27 May 2008)
> >
> > Log Message:
> > -----------
> > CRIS: Re-add the X flag to the tb flags, it allows for better code
> > generation and is practially always cleared.
> 
> Are you sure this is safe? It means you shouldn't do TB chaining from any 
> block that modifies the X flag, and I don't see any code for that.

I wouldn't expect the cris translator to handle broken X sequences (it's a TODO). I'll look into it when adding proper X flag support.

Thanks for the hint, I didn't know the target specific code was responsible for assuring flag consistency at tb chaining.

Best regards
-- 
Edgar E. Iglesias
Axis Communications AB