dnl
Alpha time stamp counter access routine.
dnl Copyright 2000, 2005 Free Software Foundation,
Inc.
dnl
This file is part of the GNU MP Library.
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; you can redistribute it and/or modify
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Public License as published by the Free
dnl Software Foundation
; either version 3 of the License, or (at your
dnl
option) any later
version.
dnl
dnl
or
dnl
dnl * the GNU General
Public License as published by the Free Software
dnl Foundation
; either version 2 of the License, or (at your option) any
dnl later
version.
dnl
dnl
or both in parallel, as here.
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dnl
or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General
Public License
dnl
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dnl You should have received copies of the GNU General
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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()
