64 lines
1.8 KiB
NASM
64 lines
1.8 KiB
NASM
dnl Pentium-4 mpn_copyd -- copy limb vector, decrementing.
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dnl
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dnl Copyright 1999, 2000, 2001 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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dnl The std/rep/movsl/cld is very slow for small blocks on pentium4. Its
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dnl startup time seems to be about 165 cycles. It then needs 2.6 c/l.
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dnl We therefore use an open-coded 2 c/l copying loop.
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dnl Ultimately, we may want to use 64-bit movq or 128-bit movdqu in some
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dnl nifty unrolled arrangement. Clearly, that could reach much higher
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dnl speeds, at least for large blocks.
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include(`../config.m4')
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defframe(PARAM_SIZE, 12)
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defframe(PARAM_SRC, 8)
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defframe(PARAM_DST, 4)
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TEXT
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ALIGN(8)
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PROLOGUE(mpn_copyd)
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deflit(`FRAME',0)
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movl PARAM_SIZE, %ecx
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movl PARAM_SRC, %eax
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movl PARAM_DST, %edx
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movl %ebx, PARAM_SIZE
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addl $-1, %ecx
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js L(end)
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L(loop):
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movl (%eax,%ecx,4), %ebx
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movl %ebx, (%edx,%ecx,4)
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addl $-1, %ecx
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jns L(loop)
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L(end):
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movl PARAM_SIZE, %ebx
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ret
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EPILOGUE()
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