1dnl  Alpha time stamp counter access routine.
2
3dnl  Copyright 2000, 2005 Free Software Foundation, Inc.
4
5dnl  This file is part of the GNU MP Library.
6dnl
7dnl  The GNU MP Library is free software; you can redistribute it and/or modify
8dnl  it under the terms of either:
9dnl
10dnl    * the GNU Lesser General Public License as published by the Free
11dnl      Software Foundation; either version 3 of the License, or (at your
12dnl      option) any later version.
13dnl
14dnl  or
15dnl
16dnl    * the GNU General Public License as published by the Free Software
17dnl      Foundation; either version 2 of the License, or (at your option) any
18dnl      later version.
19dnl
20dnl  or both in parallel, as here.
21dnl
22dnl  The GNU MP Library is distributed in the hope that it will be useful, but
23dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
24dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
25dnl  for more details.
26dnl
27dnl  You should have received copies of the GNU General Public License and the
28dnl  GNU Lesser General Public License along with the GNU MP Library.  If not,
29dnl  see https://www.gnu.org/licenses/.
30
31include(`../config.m4')
32
33
34C void speed_cyclecounter (unsigned int p[2]);
35C
36
37C The rpcc instruction returns a 64-bit value split into two 32-bit fields.
38C The lower 32 bits are set by the hardware, and the upper 32 bits are set
39C by the operating system.  The real per-process cycle count is the sum of
40C these halves.
41
42C Unfortunately, some operating systems don't get this right.  NetBSD 1.3 is
43C known to sometimes put garbage in the upper half.  Whether newer NetBSD
44C versions get it right, is unknown to us.
45
46C rpcc measures cycles elapsed in the user program and hence should be very
47C accurate even on a busy system.  Losing cache contents due to task
48C switching may have an effect though.
49
50ASM_START()
51PROLOGUE(speed_cyclecounter)
52	rpcc	r0
53	srl	r0,32,r1
54	addq	r1,r0,r0
55	stl	r0,0(r16)
56	stl	r31,4(r16)		C zero upper return word
57	ret	r31,(r26),1
58EPILOGUE(speed_cyclecounter)
59ASM_END()
60