grab header file from glibc

libc/sysdeps/linux/common/hp-timing.h

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+/* High precision, low overhead timing functions.  Generic version.
+   Copyright (C) 1998, 2000 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
+
+   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
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   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
+
+
+/* There are no generic definitions for the times.  We could write something
+   using the `gettimeofday' system call where available but the overhead of
+   the system call might be too high.
+
+   In case a platform supports timers in the hardware the following macros
+   and types must be defined:
+
+   - 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
+     values.
+
+   - HP_TIMING_ZERO: clear `hp_timing_t' object.
+
+   - HP_TIMING_NOW: place timestamp for current time in variable given as
+     parameter.
+
+   - HP_TIMING_DIFF_INIT: do whatever is necessary to be able to use the
+     HP_TIMING_DIFF macro.
+
+   - 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.
+
+*/
+
+/* Provide dummy definitions.  */
+#define HP_TIMING_AVAIL		(0)
+#define HP_TIMING_INLINE	(0)
+typedef int hp_timing_t;
+#define HP_TIMING_ZERO(Var)
+#define HP_TIMING_NOW(var)
+#define HP_TIMING_DIFF_INIT()
+#define HP_TIMING_DIFF(Diff, Start, End)
+#define HP_TIMING_ACCUM(Sum, Diff)
+#define HP_TIMING_ACCUM_NT(Sum, Diff)
+#define HP_TIMING_PRINT(Buf, Len, Val)
+
+/* Since this implementation is not available we tell the user about it.  */
+#define HP_TIMING_NONAVAIL	1
+
+#endif	/* hp-timing.h */