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dnl Intel P5 mpn_popcount -- mpn bit population count.
dnl Copyright 2001, 2002 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 P5: 8.0 cycles/limb
C unsigned long mpn_popcount (mp_srcptr src, mp_size_t size);
C
C An arithmetic approach has been found to be slower than the table lookup,
C due to needing too many instructions.
C The slightly strange quoting here helps the renaming done by tune/many.pl.
deflit(TABLE_NAME,
m4_assert_defined(`GSYM_PREFIX')
GSYM_PREFIX`'mpn_popcount``'_table')
RODATA
ALIGN(8)
GLOBL TABLE_NAME
TABLE_NAME:
forloop(i,0,255,
` .byte m4_popcount(i)
')
defframe(PARAM_SIZE,8)
defframe(PARAM_SRC, 4)
TEXT
ALIGN(8)
PROLOGUE(mpn_popcount)
deflit(`FRAME',0)
movl PARAM_SIZE, %ecx
pushl %esi FRAME_pushl()
ifdef(`PIC',`
pushl %ebx FRAME_pushl()
pushl %ebp FRAME_pushl()
call L(here)
L(here):
popl %ebp
shll %ecx C size in byte pairs
addl $_GLOBAL_OFFSET_TABLE_+[.-L(here)], %ebp
movl PARAM_SRC, %esi
xorl %eax, %eax C total
xorl %ebx, %ebx C byte
movl TABLE_NAME@GOT(%ebp), %ebp
xorl %edx, %edx C byte
define(TABLE,`(%ebp,$1)')
',`
dnl non-PIC
shll %ecx C size in byte pairs
movl PARAM_SRC, %esi
pushl %ebx FRAME_pushl()
xorl %eax, %eax C total
xorl %ebx, %ebx C byte
xorl %edx, %edx C byte
define(TABLE,`TABLE_NAME`'($1)')
')
ALIGN(8) C necessary on P55 for claimed speed
L(top):
C eax total
C ebx byte
C ecx counter, 2*size to 2
C edx byte
C esi src
C edi
C ebp [PIC] table
addl %ebx, %eax
movb -1(%esi,%ecx,2), %bl
addl %edx, %eax
movb -2(%esi,%ecx,2), %dl
movb TABLE(%ebx), %bl
decl %ecx
movb TABLE(%edx), %dl
jnz L(top)
ifdef(`PIC',`
popl %ebp
')
addl %ebx, %eax
popl %ebx
addl %edx, %eax
popl %esi
ret
EPILOGUE()
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