51 lines
1.8 KiB
NASM
51 lines
1.8 KiB
NASM
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dnl Alpha time stamp counter access routine.
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dnl Copyright 2000, 2005 Free Software Foundation, Inc.
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dnl
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dnl This file is part of the GNU MP Library.
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dnl
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dnl The GNU MP Library is free software; you can redistribute it and/or
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dnl modify it under the terms of the GNU Lesser General Public License as
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dnl published by the Free Software Foundation; either version 2.1 of the
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dnl License, or (at your option) any later version.
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dnl
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dnl The GNU MP Library is distributed in the hope that it will be useful,
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dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
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dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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dnl Lesser General Public License for more details.
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dnl
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dnl You should have received a copy of the GNU Lesser General Public
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dnl License along with the GNU MP Library; see the file COPYING.LIB. If
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dnl not, write to the Free Software Foundation, Inc., 51 Franklin Street,
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dnl Fifth Floor, Boston, MA 02110-1301, USA.
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include(`../config.m4')
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C void speed_cyclecounter (unsigned int p[2]);
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C
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C The rpcc instruction returns a 64-bit value split into two 32-bit fields.
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C The lower 32 bits are set by the hardware, and the upper 32 bits are set
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C by the operating system. The real per-process cycle count is the sum of
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C these halves.
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C Unfortunately, some operating systems don't get this right. NetBSD 1.3 is
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C known to sometimes put garbage in the upper half. Whether newer NetBSD
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C versions get it right, is unknown to us.
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C rpcc measures cycles elapsed in the user program and hence should be very
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C accurate even on a busy system. Losing cache contents due to task
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C switching may have an effect though.
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ASM_START()
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PROLOGUE(speed_cyclecounter)
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rpcc r0
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srl r0,32,r1
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addq r1,r0,r0
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stl r0,0(r16)
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stl r31,4(r16) C zero upper return word
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ret r31,(r26),1
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EPILOGUE(speed_cyclecounter)
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ASM_END()
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