[Cbe-oss-dev] [PATCH 1/2]MARS/core: Tick counter api

[Yuji Mano]

Arnd Bergmann wrote:
> On Friday 21 November 2008, Yuji Mano wrote:
>> +uint32_t mars_get_ticks(void) +{ +       return __mftb() &
>> 0xffffffff; +}
> 
> Where does the definition of __mftb come from?

It's defined in <ppu_intrinsics.h>
Documented in Language_Extensions_for_CBEA_2.4.pdf - page 90

#ifdef __powerpc64__
#define __mftb() __extension__			\
  ({ unsigned long long result;			\
  __asm__ volatile ("mftb %0" : "=r" (result));	\
  result; })
#else
#define __mftb() __extension__			\
  ({ unsigned long long result;			\
  unsigned long t;				\
  __asm__ volatile ("1:\n"			\
		    "\tmftbu %0\n"		\
		    "\tmftb %L0\n"		\
		    "\tmftbu %1\n"		\
		    "\tcmpw %0,%1\n"		\
		    "\tbne 1b"			\
		    : "=r" (result), "=r" (t));	\
  result; })
#endif /* __powerpc64__ */


> Does it have the fixup for the cell erratum reading the time base?

Maybe Andrew Pinski or someone more familiar with this has the answer?

Regards,
Yuji