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/* High precision, low overhead timing functions. Alpha version.
Copyright (C) 2001 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson <>, 2001.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef _HP_TIMING_H
#define _HP_TIMING_H 1
#include <string.h>
#include <sys/param.h>
#include <stdio-common/_itoa.h>
/* The macros defined here use the timestamp counter in IA-64. They
provide a very accurate way to measure the time with very little
overhead. The time values themself have no real meaning, only
differences are interesting.
The list of macros we need includes the following:
- HP_TIMING_AVAIL: test for availability.
- HP_TIMING_INLINE: this macro is non-zero if the functionality is not
implemented using function calls but instead uses some inlined code
which might simply consist of a few assembler instructions. We have to
know this since we might want to use the macros here in places where we
cannot make function calls.
- hp_timing_t: This is the type for variables used to store the time
- HP_TIMING_ZERO: clear `hp_timing_t' object.
- HP_TIMING_NOW: place timestamp for current time in variable given as
- HP_TIMING_DIFF_INIT: do whatever is necessary to be able to use the
- HP_TIMING_DIFF: compute difference between two times and store it
in a third. Source and destination might overlap.
- HP_TIMING_ACCUM: add time difference to another variable. This might
be a bit more complicated to implement for some platforms as the
operation should be thread-safe and 64bit arithmetic on 32bit platforms
is not.
- HP_TIMING_ACCUM_NT: this is the variant for situations where we know
there are no threads involved.
- HP_TIMING_PRINT: write decimal representation of the timing value into
the given string. This operation need not be inline even though
HP_TIMING_INLINE is specified.
/* We always have the timestamp register, but it's got only a 4 second
range. Use it for profiling only. */
#define HP_TIMING_AVAIL (0)
/* We indeed have inlined functions. */
#define HP_TIMING_INLINE (1)
/* We use 32 bit values for the times. */
typedef unsigned int hp_timing_t;
/* Set timestamp value to zero. */
#define HP_TIMING_ZERO(VAR) (VAR) = (0)
/* The "rpcc" instruction returns a 32-bit counting half and a 32-bit
"virtual cycle counter displacement". Subtracting the two gives us
a virtual cycle count. */
#define HP_TIMING_NOW(VAR) \
do { \
unsigned long int x_; \
asm volatile ("rpcc %0" : "=r"(x_)); \
(VAR) = (int) (x_) - (int) (x_ >> 32); \
} while (0)
/* ??? Two rpcc instructions can be scheduled simultaneously. */
#define HP_TIMING_DIFF_INIT() do { } while (0)
/* It's simple arithmetic for us. */
#define HP_TIMING_DIFF(Diff, Start, End) (Diff) = ((End) - (Start))
/* ??? Don't bother, since we're only used for */
#define HP_TIMING_ACCUM(Sum, Diff) not implemented
/* No threads, no extra work. */
#define HP_TIMING_ACCUM_NT(Sum, Diff) (Sum) += (Diff)
/* Print the time value. */
#define HP_TIMING_PRINT(Buf, Len, Val) \
do { \
char __buf[20]; \
char *__cp = _itoa_word (Val, __buf + sizeof (__buf), 10, 0); \
int __len = (Len); \
char *__dest = (Buf); \
while (__len-- > 0 && __cp < __buf + sizeof (__buf)) \
*__dest++ = *__cp++; \
memcpy (__dest, " clock cycles", MIN (__len, sizeof (" clock cycles"))); \
} while (0)
#endif /* hp-timing.h */