On Fri, Jan 04, 2013 at 10:39:05PM +0100, Leif Ekblad wrote:
I just tried the patch, but it seems to produce some problems for
me. The other patch which used a 64-bit specific register (r15)
instead of rbx was easier to adapt to. The problem for me is that
syscalls might clobber higher-half of
hjl.to...@gmail.com
Sent: Friday, January 04, 2013 10:42 PM
Subject: Re: [RFC PATCH, i386]: Use %r15 for REAL_PIC_OFFSET_TABLE_REGNUM on
x86_64
On Fri, Jan 04, 2013 at 10:39:05PM +0100, Leif Ekblad wrote:
I just tried the patch, but it seems to produce some problems for
me. The other patch which
On Fri, Dec 28, 2012 at 9:27 PM, Richard Henderson r...@redhat.com wrote:
On 12/27/2012 12:08 AM, Uros Bizjak wrote:
The alternative approach is changing cpuid definition in cpuid.h (as
in attached patch) to preserve %rbx, but we can't detect various code
model settings there. Since the change
On 12/27/2012 12:08 AM, Uros Bizjak wrote:
The alternative approach is changing cpuid definition in cpuid.h (as
in attached patch) to preserve %rbx, but we can't detect various code
model settings there. Since the change depends on the definition of
__PIC__, we unnecessary preserve %rbx also
On Wed, Dec 26, 2012 at 9:16 PM, Andi Kleen a...@firstfloor.org wrote:
Can you please post a real-world example, where using %r15 would break
existing code?
I used to run into problems like this when porting code to gcc from icc or VC.
A lot of hyper optimized inline assembler snippets wants
On Thu, Dec 27, 2012 at 9:08 AM, Uros Bizjak ubiz...@gmail.com wrote:
On Wed, Dec 26, 2012 at 9:16 PM, Andi Kleen a...@firstfloor.org wrote:
Can you please post a real-world example, where using %r15 would break
existing code?
I used to run into problems like this when porting code to gcc
* Uros Bizjak:
+#elif defined(__x86_64__)
+#define __cpuid(level, a, b, c, d) \
+ __asm__ (xchg{q}\t{%%}rbx, %q1\n\t \
+cpuid\n\t \
+xchg{q}\t{%%}rbx, %q1\n\t \
+: =a (a), =r
On Thu, Dec 27, 2012 at 10:10 AM, Florian Weimer f...@deneb.enyo.de wrote:
* Uros Bizjak:
+#elif defined(__x86_64__)
+#define __cpuid(level, a, b, c, d) \
+ __asm__ (xchg{q}\t{%%}rbx, %q1\n\t \
+cpuid\n\t \
+
On Tue, Dec 25, 2012 at 8:27 PM, Mike Frysinger vap...@gentoo.org wrote:
In the case of cpuid, the code is hardly performance sensitive, and
probably runs only at startup. An alternative solution for the broken
code here is to move the result from rbx to another register, and to
Can you please post a real-world example, where using %r15 would break
existing code?
I used to run into problems like this when porting code to gcc from icc or VC.
A lot of hyper optimized inline assembler snippets wants to use all registers
and icc/VC support that. With gcc usually had to add
On Tue, Dec 25, 2012 at 6:54 AM, Mike Frysinger vap...@gentoo.org wrote:
On Monday 24 December 2012 17:26:47 Leif Ekblad wrote:
In the case of cpuid, the code is hardly performance sensitive, and
probably runs only at startup. An alternative solution for the broken code
here is to move the
On Tuesday 25 December 2012 14:12:09 Uros Bizjak wrote:
On Tue, Dec 25, 2012 at 6:54 AM, Mike Frysinger vap...@gentoo.org wrote:
On Monday 24 December 2012 17:26:47 Leif Ekblad wrote:
In the case of cpuid, the code is hardly performance sensitive, and
probably runs only at startup. An
Hello!
Currently, we use %rbx as REAL_PIC_OFFSET_TABLE_REGNUM on x86_64.
Since this register gets marked as fixed reg in
ix86_conditional_register_usage, we get into troubles with insns that
use %rbx (cmpxchg, cpuid). According to x86_64 psABI, we are free to
use any register, so attached patch
Uros Bizjak ubiz...@gmail.com writes:
Hello!
Currently, we use %rbx as REAL_PIC_OFFSET_TABLE_REGNUM on x86_64.
Since this register gets marked as fixed reg in
ix86_conditional_register_usage, we get into troubles with insns that
use %rbx (cmpxchg, cpuid). According to x86_64 psABI, we are
10:32 PM
Subject: Re: [RFC PATCH, i386]: Use %r15 for REAL_PIC_OFFSET_TABLE_REGNUM on
x86_64
Uros Bizjak ubiz...@gmail.com writes:
Hello!
Currently, we use %rbx as REAL_PIC_OFFSET_TABLE_REGNUM on x86_64.
Since this register gets marked as fixed reg in
ix86_conditional_register_usage, we get
On Monday 24 December 2012 17:26:47 Leif Ekblad wrote:
In the case of cpuid, the code is hardly performance sensitive, and
probably runs only at startup. An alternative solution for the broken code
here is to move the result from rbx to another register, and to
save/restore rbx. Currently,
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