mpir/mpn/x86/nehalem/popcount.asm
2013-08-01 19:07:47 +02:00

189 lines
3.9 KiB
NASM

dnl Intel Pentium 4 mpn_popcount, mpn_hamdist -- population count and
dnl hamming distance.
dnl Copyright 2000, 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 2.1 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
dnl License along with the GNU MP Library; see the file COPYING.LIB. If
dnl not, write to the Free Software Foundation, Inc., 51 Franklin Street,
dnl Fifth Floor, Boston, MA 02110-1301, USA.
include(`../config.m4')
C P4: popcount 8.5 cycles/limb
C hamdist 9.5 cycles/limb
C unsigned long mpn_popcount (mp_srcptr src, mp_size_t size);
C unsigned long mpn_hamdist (mp_srcptr src, mp_srcptr src2, mp_size_t size);
C
C Loading with unaligned movq's costs an extra 1 c/l and hence is avoided.
C Two movd's and a punpckldq seems to be the same speed as an aligned movq,
C and using them saves fiddling about with alignment testing on entry.
C
C For popcount there's 13 mmx instructions in the loop, so perhaps 6.5 c/l
C might be possible, but 8.5 c/l relying on out-of-order execution is
C already quite reasonable.
define(`OPERATION_popcount',1)
ifdef(`OPERATION_popcount',,
`ifdef(`OPERATION_hamdist',,
`m4_error(`Need OPERATION_popcount or OPERATION_hamdist defined
')')')
define(HAM,
m4_assert_numargs(1)
`ifdef(`OPERATION_hamdist',`$1')')
define(POP,
m4_assert_numargs(1)
`ifdef(`OPERATION_popcount',`$1')')
HAM(`
defframe(PARAM_SIZE, 12)
defframe(PARAM_SRC2, 8)
defframe(PARAM_SRC, 4)
define(M4_function,mpn_hamdist)
')
POP(`
defframe(PARAM_SIZE, 8)
defframe(PARAM_SRC, 4)
define(M4_function,mpn_popcount)
')
ifdef(`PIC',,`
dnl non-PIC
RODATA
ALIGN(8)
L(rodata_AAAAAAAAAAAAAAAA):
.long 0xAAAAAAAA
.long 0xAAAAAAAA
L(rodata_3333333333333333):
.long 0x33333333
.long 0x33333333
L(rodata_0F0F0F0F0F0F0F0F):
.long 0x0F0F0F0F
.long 0x0F0F0F0F
')
TEXT
ALIGN(16)
PROLOGUE(M4_function)
deflit(`FRAME',0)
movl PARAM_SIZE, %ecx
movl PARAM_SRC, %eax
ifdef(`PIC',`
movl $0xAAAAAAAA, %edx
movd %edx, %mm7
punpckldq %mm7, %mm7
movl $0x33333333, %edx
movd %edx, %mm6
punpckldq %mm6, %mm6
movl $0x0F0F0F0F, %edx
movd %edx, %mm5
punpckldq %mm5, %mm5
HAM(` movl PARAM_SRC2, %edx')
',`
dnl non-PIC
HAM(` movl PARAM_SRC2, %edx')
movq L(rodata_AAAAAAAAAAAAAAAA), %mm7
movq L(rodata_3333333333333333), %mm6
movq L(rodata_0F0F0F0F0F0F0F0F), %mm5
')
pxor %mm4, %mm4 C zero
pxor %mm0, %mm0 C total
subl $1, %ecx
ja L(top)
L(last):
movd (%eax,%ecx,4), %mm1 C src high limb
HAM(` movd (%edx,%ecx,4), %mm2
pxor %mm2, %mm1
')
jmp L(loaded)
L(top):
C eax src
C ebx
C ecx counter, size-1 to 2 or 1, inclusive
C edx [hamdist] src2
C
C mm0 total (low dword)
C mm1 (scratch)
C mm2 (scratch)
C mm3
C mm4 0x0000000000000000
C mm5 0x0F0F0F0F0F0F0F0F
C mm6 0x3333333333333333
C mm7 0xAAAAAAAAAAAAAAAA
movd (%eax), %mm1
movd 4(%eax), %mm2
punpckldq %mm2, %mm1
addl $8, %eax
HAM(` movd (%edx), %mm2
movd 4(%edx), %mm3
punpckldq %mm3, %mm2
pxor %mm2, %mm1
addl $8, %edx
')
L(loaded):
movq %mm7, %mm2
pand %mm1, %mm2
psrlq $1, %mm2
psubd %mm2, %mm1 C bit pairs
movq %mm6, %mm2
pand %mm1, %mm2
psrlq $2, %mm1
pand %mm6, %mm1
paddd %mm2, %mm1 C nibbles
movq %mm5, %mm2
pand %mm1, %mm2
psrlq $4, %mm1
pand %mm5, %mm1
paddd %mm2, %mm1 C bytes
psadbw( %mm4, %mm1)
paddd %mm1, %mm0 C to total
subl $2, %ecx
jg L(top)
C ecx is 0 or -1 representing respectively 1 or 0 further limbs
jz L(last)
movd %mm0, %eax
emms
ret
EPILOGUE()