dnl AMD64 mpn_invert_limb -- Invert a normalized limb.
dnl Contributed to the GNU project by Torbjorn Granlund
and Niels Möller.
dnl Copyright 2004, 2007-2009, 2011, 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 (approx)
div
C AMD K8,K9 48 71
C AMD K10 48 77
C Intel P4 135 161
C Intel core2 69 116
C Intel corei 55 89
C Intel atom 129 191
C VIA nano 79 157
C rax rcx rdx rdi rsi r8
ABI_SUPPORT(DOS64)
ABI_SUPPORT(STD64)
PROTECT(`mpn_invert_limb_table
')
ASM_START()
TEXT
ALIGN(16)
PROLOGUE(mpn_invert_limb) C Kn C2 Ci
FUNC_ENTRY(1)
mov %rdi, %rax C 0 0 0
shr $55, %rax C 1 1 1
ifdef(`DARWIN
',`
lea mpn_invert_limb_table(%rip), %r8
add $-512, %r8
',`
lea -512+mpn_invert_limb_table(%rip), %r8
')
movzwl (%r8,%rax,2), R32(%rcx) C %rcx = v0
C v1 = (v0 << 11) - (v0*v0*d40 >> 40) - 1
mov %rdi, %rsi C 0 0 0
mov R32(%rcx), R32(%rax) C 4 5 5
imul R32(%rcx), R32(%rcx) C 4 5 5
shr $24, %rsi C 1 1 1
inc %rsi C %rsi = d40
imul %rsi, %rcx C 8 10 8
shr $40, %rcx C 12 15 11
sal $11, R32(%rax) C 5 6 6
dec R32(%rax)
sub R32(%rcx), R32(%rax) C %rax = v1
C v2 = (v1 << 13) + (v1 * (2^60 - v1*d40) >> 47)
mov $0x1000000000000000, %rcx
imul %rax, %rsi C 14 17 13
sub %rsi, %rcx
imul %rax, %rcx
sal $13, %rax
shr $47, %rcx
add %rax, %rcx C %rcx = v2
C v3 = (v2 << 31) + (v2 * (2^96 - v2 * d63 + ((v2 >> 1) &
mask)) >> 65)
mov %rdi, %rsi C 0 0 0
shr %rsi C d/2
sbb %rax, %rax C -d0 = -(d
mod 2)
sub %rax, %rsi C d63 = ceil(d/2)
imul %rcx, %rsi C v2 * d63
and %rcx, %rax C v2 * d0
shr %rax C (v2>>1) * d0
sub %rsi, %rax C (v2>>1) * d0 - v2 * d63
mul %rcx
sal $31, %rcx
shr %rdx
add %rdx, %rcx C %rcx = v3
mov %rdi, %rax
mul %rcx
add %rdi, %rax
mov %rcx, %rax
adc %rdi, %rdx
sub %rdx, %rax
FUNC_EXIT()
ret
EPILOGUE()
ASM_END()
