For things that do mftb with high frequency, maybe you should
also add a
builtin that does just an mftb, i.e. returns a 32-bit result on
32-bit
implementations.
Are you thinking in a function that returns only the TBL?
On 32-bit, just TBL; on 64-bit, the whole TB (there is no machine
instr
On Wed, Aug 29, 2012 at 3:09 PM, Segher Boessenkool
wrote:
>>> For things that do mftb with high frequency, maybe you should also add a
>>> builtin that does just an mftb, i.e. returns a 32-bit result on 32-bit
>>> implementations.
>>
>> Are you thinking in a function that returns only the TBL?
>
Point being, for simulator environments, you may not want the
loop that was suggested later. On the other hand, that might
not be an observable period, either.
I don't think looping a million times would be too slow for the
testsuite: there are many tests that do a lot more work than that,
alre
Segher Boessenkool writes:
For things that do mftb with high frequency, maybe you should
also add a
builtin that does just an mftb, i.e. returns a 32-bit result
on 32-
bit
implementations.
Are you thinking in a function that returns only the TBL?
On 32-bit, just TBL; on 64-bit, the whole
On Wed, 29 Aug 2012, Michael Meissner wrote:
> On Wed, Aug 29, 2012 at 01:56:05PM -0400, Hans-Peter Nilsson wrote:
> > On Wed, 29 Aug 2012, Segher Boessenkool wrote:
> > > On some systems the timebase runs at a rather low frequency, say 20MHz.
> > > This test will spuriously fail there. Waste a mi
For things that do mftb with high frequency, maybe you should also
add a
builtin that does just an mftb, i.e. returns a 32-bit result on 32-
bit
implementations.
Are you thinking in a function that returns only the TBL?
On 32-bit, just TBL; on 64-bit, the whole TB (there is no machine
instr
On some systems the timebase runs at a rather low frequency, say
20MHz.
This test will spuriously fail there. Waste a million CPU cycles
before
reading TB the second time?
Waste said million cycles portably by calling sched_yield()?
(Available only on POSIX systems. :)
I was thinking more
Hi Segher,
Segher Boessenkool writes:
Add __builtin_ppc_get_timebase to read the time base register
on PowerPC.
This is required for applications that measure time at high
frequencies
with high precision that can't afford a syscall.
For things that do mftb with high frequency, maybe you sh
On Wed, Aug 29, 2012 at 01:56:05PM -0400, Hans-Peter Nilsson wrote:
> On Wed, 29 Aug 2012, Segher Boessenkool wrote:
> > On some systems the timebase runs at a rather low frequency, say 20MHz.
> > This test will spuriously fail there. Waste a million CPU cycles before
> > reading TB the second tim
On Wed, 29 Aug 2012, Segher Boessenkool wrote:
> > +++ b/gcc/testsuite/gcc.target/powerpc/ppc-get-timebase.c
> > @@ -0,0 +1,22 @@
> > +/* { dg-do run { target { powerpc*-*-* } } } */
> > +
> > +/* Test if __builtin_ppc_get_timebase() is compatible with the current
> > + processor and if it's chan
On Wed, Aug 29, 2012 at 6:56 AM, Tulio Magno Quites Machado Filho
wrote:
> Add __builtin_ppc_get_timebase to read the time base register on PowerPC.
> This is required for applications that measure time at high frequencies
> with high precision that can't afford a syscall.
>
> [gcc]
> 2012-08-29 T
Hi Tulio,
Add __builtin_ppc_get_timebase to read the time base register on
PowerPC.
This is required for applications that measure time at high
frequencies
with high precision that can't afford a syscall.
For things that do mftb with high frequency, maybe you should also add a
builtin that
Add __builtin_ppc_get_timebase to read the time base register on PowerPC.
This is required for applications that measure time at high frequencies
with high precision that can't afford a syscall.
[gcc]
2012-08-29 Tulio Magno Quites Machado Filho
* config/rs6000/rs6000-builtin.def: Add __b
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