dnl  x86-64 mpn_div_qr_2u_pi1

dnl  -- Divide an mpn number by an unnormalized 2-limb number,

dnl     using a single-limb inverse and shifting the dividend on the fly.

dnl  Copyright 2007, 2008, 2010, 2011 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		c/l

C INPUT PARAMETERS

define(`qp',		`%rdi')

define(`rp',		`%rsi')

define(`up_param',	`%rdx')

define(`un_param',	`%rcx') dnl %rcx needed for shift count

define(`d1',		`%r8')

define(`d0',		`%r9')

define(`shift_param',	`FRAME+8(%rsp)')

define(`di_param',	`FRAME+16(%rsp)')

define(`di',		`%r10')

define(`up',		`%r11')

define(`un',		`%rbp')

define(`u2',		`%rbx')

define(`u1',		`%r12')

define(`u0',		`%rsi') dnl Same as rp, which is saved and restored.

define(`t1',		`%r13')

define(`t0',		`%r14')

define(`md1',		`%r15')

ASM_START()

	TEXT

	ALIGN(16)

deflit(`FRAME', 0)

PROLOGUE(mpn_div_qr_2u_pi1)

	mov	di_param, di

	mov	up_param, up

	push	%r15

	push	%r14

	push	%r13

	push	%r12

	push	%rbx

	push	%rbp

	push	rp

deflit(`FRAME', 56)

	lea	-2(un_param), un

	mov	d1, md1

	neg	md1

	C int parameter, 32 bits only

	movl	shift_param, R32(%rcx)

	C FIXME: Different code for SHLD_SLOW

	xor	R32(u2), R32(u2)

	mov	8(up, un, 8), u1

	shld	%cl, u1, u2

	C Remains to read (up, un, 8) and shift u1, u0

	C udiv_qr_3by2 (qh,u2,u1,u2,u1,n0, d1,d0,di)

	mov	di, %rax

	mul	u2

	mov	(up, un, 8), u0

	shld	%cl, u0, u1

	mov	u1, t0

	add	%rax, t0	C q0 in t0

	adc	u2, %rdx

	mov	%rdx, t1	C q in t1

	imul	md1, %rdx

	mov	d0, %rax

	lea	(%rdx, u1), u2

	mul	t1

	mov	u0, u1

	shl	%cl, u1

	sub	d0, u1

	sbb	d1, u2

	sub	%rax, u1

	sbb	%rdx, u2

	xor	R32(%rax), R32(%rax)

	xor	R32(%rdx), R32(%rdx)

	cmp	t0, u2

	cmovnc	d0, %rax

	cmovnc	d1, %rdx

	adc	$0, t1

	nop

	add	%rax, u1

	adc	%rdx, u2

	cmp	d1, u2

	jae	L(fix_qh)

L(bck_qh):

	push	t1	C push qh on stack

	jmp	L(next)

	ALIGN(16)

L(loop):

	C udiv_qr_3by2 (q,u2,u1,u2,u1,n0, d1,d0,di)

	C Based on the optimized divrem_2.asm code.

	mov	di, %rax

	mul	u2

	mov	(up, un, 8), u0

	xor	R32(t1), R32(t1)

	shld	%cl, u0, t1

	or	t1, u1

	mov	u1, t0

	add	%rax, t0	C q0 in t0

	adc	u2, %rdx

	mov	%rdx, t1	C q in t1

	imul	md1, %rdx

	mov	d0, %rax

	lea	(%rdx, u1), u2

	mul	t1

	mov	u0, u1

	shl	%cl, u1

	sub	d0, u1

	sbb	d1, u2

	sub	%rax, u1

	sbb	%rdx, u2

	xor	R32(%rax), R32(%rax)

	xor	R32(%rdx), R32(%rdx)

	cmp	t0, u2

	cmovnc	d0, %rax

	cmovnc	d1, %rdx

	adc	$0, t1

	nop

	add	%rax, u1

	adc	%rdx, u2

	cmp	d1, u2

	jae	L(fix)

L(bck):

	mov	t1, (qp, un, 8)

L(next):

	sub	$1, un

	jnc	L(loop)

L(end):

	C qh on stack

	pop	%rax

	pop	rp

	shrd	%cl, u2, u1

	shr	%cl, u2

	mov	u2, 8(rp)

	mov	u1, (rp)

	pop	%rbp

	pop	%rbx

	pop	%r12

	pop	%r13

	pop	%r14

	pop	%r15

	ret

L(fix):	C Unlikely update. u2 >= d1

	seta	%dl

	cmp	d0, u1

	setae	%al

	orb	%dl, %al		C "orb" form to placate Sun tools

	je	L(bck)

	inc	t1

	sub	d0, u1

	sbb	d1, u2

	jmp	L(bck)

C Duplicated, just jumping back to a different address.

L(fix_qh):	C Unlikely update. u2 >= d1

	seta	%dl

	cmp	d0, u1

	setae	%al

	orb	%dl, %al		C "orb" form to placate Sun tools

	je	L(bck_qh)

	inc	t1

	sub	d0, u1

	sbb	d1, u2

	jmp	L(bck_qh)

EPILOGUE()

CF_PROT