[FFmpeg-devel] [PATCH] read_time() for SPARC

[Måns Rullgård]

Michael Kostylev <michael.kostylev at gmail.com> writes:

> On Tue Sep  7 22:21:56 2010
> M?ns Rullg?rd wrote:
>
>>> The attached patch provides access to a 63-bit tick counter which is
>>> available on the v9 cpus in the manner compatible with the v8+ abi.
>>>
>>> +#ifndef AVUTIL_SPARC_TIMER_H
>>> +#define AVUTIL_SPARC_TIMER_H
>>> +
>>> +#ifdef __sparc_v9__
>>> +
>>> +#include <stdint.h>
>>> +
>>> +#define AV_READ_TIME read_time
>>> +
>>> +static inline uint64_t read_time(void)
>>> +{
>>> +    uint64_t tc;
>>> +    __asm__ volatile("rd %%tick,%%g1\n\t"
>>> +                     "stx %%g1,%0\n\t"
>>> +                     : "=m" (tc) :: "g1");
>>> +    return tc;
>>> +}
>>
>>Why can't you read the counter directly to whatever register 'tc'
>>lives in?
>
> That will not work with v8+, tc will be filled with the least significant
> 32 bits.

Why?

-- 
M?ns Rullg?rd
mans at mansr.com