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/*
Copyright (C) 2001 Paul Davis
Code derived from various headers from the Linux kernel
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
$Id: cycles.h,v 1.4.2.1 2006/06/20 14:44:00 letz Exp $
*/
#ifndef __jack_cycles_h__
#define __jack_cycles_h__
/*
* Standard way to access the cycle counter on i586+ CPUs.
* Currently only used on SMP.
*
* If you really have a SMP machine with i486 chips or older,
* compile for that, and this will just always return zero.
* That's ok, it just means that the nicer scheduling heuristics
* won't work for you.
*
* We only use the low 32 bits, and we'd simply better make sure
* that we reschedule before that wraps. Scheduling at least every
* four billion cycles just basically sounds like a good idea,
* regardless of how fast the machine is.
*/
#ifdef __linux__
#ifdef __PPC__
/* PowerPC */
#define CPU_FTR_601 0x00000100
typedef unsigned long cycles_t;
/* For the "cycle" counter we use the timebase lower half. */
extern cycles_t cacheflush_time;
static inline cycles_t get_cycles(void)
{
cycles_t ret = 0;
__asm__ __volatile__(
"98: mftb %0\n"
"99:\n"
".section __ftr_fixup,\"a\"\n"
" .long %1\n"
" .long 0\n"
" .long 98b\n"
" .long 99b\n"
".previous"
: "=r" (ret) : "i" (CPU_FTR_601));
return ret;
}
#endif
#ifdef __i386__
typedef unsigned long long cycles_t;
extern cycles_t cacheflush_time;
#define rdtscll(val) \
__asm__ __volatile__("rdtsc" : "=A" (val))
static inline cycles_t get_cycles (void)
{
unsigned long long ret;
rdtscll(ret);
return ret;
}
#endif
#endif
#endif /* __jack_cycles_h__ */
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