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(`PIC',`

ifdef(`DARWIN',`

	mov	mpn_invert_limb_table@GOTPCREL(%rip), %r8

	add	$-512, %r8

',`

	lea	-512+mpn_invert_limb_table(%rip), %r8

')',`

	movabs	$-512+mpn_invert_limb_table, %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()

CF_PROT