dnl AMD64 mpn_popcount -- population count.
dnl Copyright 2008, 2010-2012 Free Software Foundation,
Inc.
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 modify
dnl it under the terms of either:
dnl
dnl * the GNU Lesser General
Public License as published by the Free
dnl Software Foundation
; either version 3 of the License, or (at your
dnl
option) any later
version.
dnl
dnl
or
dnl
dnl * the GNU General
Public License as published by the Free Software
dnl Foundation
; either version 2 of the License, or (at your option) any
dnl later
version.
dnl
dnl
or both in parallel, as here.
dnl
dnl The GNU MP 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 General
Public License
dnl
for more details.
dnl
dnl You should have received copies of the GNU General
Public License
and the
dnl GNU Lesser General
Public License along with the GNU MP Library.
If not,
dnl see
https://www.gnu.org/licenses/.
include(`../config.m4
')
C cycles/limb
C AMD K8,K9 n/a
C AMD K10 1.125
C Intel P4 n/a
C Intel core2 n/a
C Intel corei 1.25
C Intel atom n/a
C VIA nano n/a
C * The zero-offset of popcount is misassembled to the offset-less form, which
C is one
byte shorter
and therefore will mess up the switching
code.
C * The outdated gas used in FreeBSD
and NetBSD cannot handle the POPCNT insn,
C which is the main reason
for our usage of
'.byte'.
C TODO
C * Improve switching
code, the current
code sucks.
define(`up
', `%rdi')
define(`n
', `%rsi')
ABI_SUPPORT(DOS64)
ABI_SUPPORT(STD64)
ASM_START()
TEXT
ALIGN(32)
PROLOGUE(mpn_popcount)
FUNC_ENTRY(2)
ifelse(1,1,`
lea (up,n,8), up
C
mov R32(n), R32(%rcx)
C
neg R32(%rcx)
imul $-1, R32(n), R32(%rcx)
and $8-1, R32(%rcx)
neg n
mov R32(%rcx), R32(%rax)
neg %rax
lea (up,%rax,8),up
xor R32(%rax), R32(%rax)
lea (%rcx,%rcx,4), %rcx
lea L(top)(%rip), %rdx
lea (%rdx,%rcx,2), %rdx
jmp *%rdx
',`
lea (up,n,8), up
mov R32(n), R32(%rcx)
neg R32(%rcx)
and $8-1, R32(%rcx)
neg n
mov R32(%rcx), R32(%rax)
shl $3, R32(%rax)
sub %rax, up
xor R32(%rax), R32(%rax)
C
add R32(%rcx), R32(%rcx) C 2x
C
lea (%rcx,%rcx,4), %rcx C 10x
imul $10, R32(%rcx)
lea L(top)(%rip), %rdx
add %rcx, %rdx
jmp *%rdx
')
ALIGN(32)
L(top):
C 0 = n
mod 8
.
byte 0xf3,0x4c,0x0f,0xb8,0x44,0xf7,0x00 C popcnt 0(up,n,8), %r8
add %r8, %rax
C 7 = n
mod 8
.
byte 0xf3,0x4c,0x0f,0xb8,0x4c,0xf7,0x08 C popcnt 8(up,n,8), %r9
add %r9, %rax
C 6 = n
mod 8
.
byte 0xf3,0x4c,0x0f,0xb8,0x44,0xf7,0x10 C popcnt 16(up,n,8), %r8
add %r8, %rax
C 5 = n
mod 8
.
byte 0xf3,0x4c,0x0f,0xb8,0x4c,0xf7,0x18 C popcnt 24(up,n,8), %r9
add %r9, %rax
C 4 = n
mod 8
.
byte 0xf3,0x4c,0x0f,0xb8,0x44,0xf7,0x20 C popcnt 32(up,n,8), %r8
add %r8, %rax
C 3 = n
mod 8
.
byte 0xf3,0x4c,0x0f,0xb8,0x4c,0xf7,0x28 C popcnt 40(up,n,8), %r9
add %r9, %rax
C 2 = n
mod 8
.
byte 0xf3,0x4c,0x0f,0xb8,0x44,0xf7,0x30 C popcnt 48(up,n,8), %r8
add %r8, %rax
C 1 = n
mod 8
.
byte 0xf3,0x4c,0x0f,0xb8,0x4c,0xf7,0x38 C popcnt 56(up,n,8), %r9
add %r9, %rax
add $8, n
js L(top)
FUNC_EXIT()
ret
EPILOGUE()
