mpir/mpn/x86_64/nehalem/popcount.asm
2010-12-04 14:29:18 +00:00

67 lines
1.7 KiB
NASM

dnl mpn_popcount
dnl Copyright 2010 The Code Cavern
dnl This file is part of the MPIR Library.
dnl The MPIR Library is free software; you can redistribute it and/or modify
dnl it under the terms of the GNU Lesser General Public License as published
dnl by the Free Software Foundation; either version 2.1 of the License, or (at
dnl your option) any later version.
dnl The MPIR Library is distributed in the hope that it will be useful, but
dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
dnl License for more details.
dnl You should have received a copy of the GNU Lesser General Public License
dnl along with the MPIR Library; see the file COPYING.LIB. If not, write
dnl to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
dnl Boston, MA 02110-1301, USA.
include(`../config.m4')
ASM_START()
PROLOGUE(mpn_popcount)
mov $5,%rcx
lea -40(%rdi,%rsi,8),%rdi
xor %eax,%eax
sub %rsi,%rcx
jnc skiplp
ALIGN(16)
lp:
popcnt (%rdi,%rcx,8),%r8
popcnt 8(%rdi,%rcx,8),%r9
popcnt 16(%rdi,%rcx,8),%r10
popcnt 24(%rdi,%rcx,8),%rsi
add %r8,%rax
add %rsi,%rax
add %r9,%rax
popcnt 32(%rdi,%rcx,8),%r8
popcnt 40(%rdi,%rcx,8),%r9
add %r8,%rax
add %r10,%rax
add %r9,%rax
add $6,%rcx
jnc lp
skiplp:
lea case5(%rip),%rdx #// in linux we can do this before the loop
lea (%rcx,%rcx,8),%rcx #// rcx*9
add %rcx,%rdx
jmp *%rdx
case5: #//rcx=0
nop
popcnt (%rdi),%r8 #// 5bytes
add %r8,%rax #// 3bytes
case4: #//rcx=1
popcnt 8(%rdi),%r9 #// 6bytes
add %r9,%rax
case3: popcnt 16(%rdi),%r10
add %r10,%rax
case2: popcnt 24(%rdi),%rsi
add %rsi,%rax
case1: popcnt 32(%rdi),%r8
add %r8,%rax
case0: ret
EPILOGUE()