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dnl Alpha time stamp counter access routine.
dnl Copyright 2000, 2005 Free Software Foundation, Inc.
dnl
dnl This file is part of the GNU MP Library.
dnl
dnl The GNU MP Library is free software; you can redistribute it and/or
dnl modify it under the terms of the GNU Lesser General Public License as
dnl published by the Free Software Foundation; either version 3 of the
dnl License, or (at your option) any later version.
dnl
dnl The GNU MP Library is distributed in the hope that it will be useful,
dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
dnl Lesser General Public License for more details.
dnl
dnl You should have received a copy of the GNU Lesser General Public License
dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/.
include(`../config.m4')
C void speed_cyclecounter (unsigned int p[2]);
C
C The rpcc instruction returns a 64-bit value split into two 32-bit fields.
C The lower 32 bits are set by the hardware, and the upper 32 bits are set
C by the operating system. The real per-process cycle count is the sum of
C these halves.
C Unfortunately, some operating systems don't get this right. NetBSD 1.3 is
C known to sometimes put garbage in the upper half. Whether newer NetBSD
C versions get it right, is unknown to us.
C rpcc measures cycles elapsed in the user program and hence should be very
C accurate even on a busy system. Losing cache contents due to task
C switching may have an effect though.
ASM_START()
PROLOGUE(speed_cyclecounter)
rpcc r0
srl r0,32,r1
addq r1,r0,r0
stl r0,0(r16)
stl r31,4(r16) C zero upper return word
ret r31,(r26),1
EPILOGUE(speed_cyclecounter)
ASM_END()
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