dnl  ARM v6 mpn_divexact_1

dnl  Contributed to the GNU project by Torbjörn Granlund.

dnl  Copyright 2012, 2013 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       cycles/limb

C               norm    unorm    modexact_1c_odd

C StrongARM	 -	 -

C XScale	 -	 -

C Cortex-A7	 ?	 ?

C Cortex-A8	 ?	 ?

C Cortex-A9	 9	10		 9

C Cortex-A15	 7	 7		 7

C Architecture requirements:

C v5	-

C v5t	clz

C v5te	-

C v6	umaal

C v6t2	-

C v7a	-

define(`rp', `r0')

define(`up', `r1')

define(`n',  `r2')

define(`d',  `r3')

define(`cy',  `r7')

define(`cnt', `r6')

define(`tnc', `r10')

ASM_START()

PROLOGUE(mpn_divexact_1)

	push	{r4,r5,r6,r7,r8,r9}

	tst	d, #1

	rsb	r4, d, #0

	and	r4, r4, d

	clz	r4, r4

	rsb	cnt, r4, #31		C count_trailing_zeros

	mov	d, d, lsr cnt

C binvert limb

	LEA(	r4, binvert_limb_table)

	and	r12, d, #254

	ldrb	r4, [r4, r12, lsr #1]

	mul	r12, r4, r4

	mul	r12, d, r12

	rsb	r12, r12, r4, lsl #1

	mul	r4, r12, r12

	mul	r4, d, r4

	rsb	r4, r4, r12, lsl #1	C r4 = inverse

	ldr	r5, [up], #4		C up[0]

	mov	cy, #0

	rsb	r8, r4, #0		C r8 = -inverse

	beq	L(unnorm)

L(norm):

	subs	n, n, #1

	mul	r5, r5, r4

	beq	L(end)

	ALIGN(16)

L(top):	ldr	r9, [up], #4

	mov	r12, #0

	str	r5, [rp], #4

	umaal	r12, cy, r5, d

	mul	r5, r9, r4

	mla	r5, cy, r8, r5

	subs	n, n, #1

	bne	L(top)

L(end):	str	r5, [rp]

	pop	{r4,r5,r6,r7,r8,r9}

	bx	r14

L(unnorm):

	push	{r10,r11}

	rsb	tnc, cnt, #32

	mov	r11, r5, lsr cnt

	subs	n, n, #1

	beq	L(edx)

	ldr	r12, [up], #4

	orr	r9, r11, r12, lsl tnc

	mov	r11, r12, lsr cnt

	mul	r5, r9, r4

	subs	n, n, #1

	beq	L(edu)

	ALIGN(16)

L(tpu):	ldr	r12, [up], #4

	orr	r9, r11, r12, lsl tnc

	mov	r11, r12, lsr cnt

	mov	r12, #0

	str	r5, [rp], #4

	umaal	r12, cy, r5, d

	mul	r5, r9, r4

	mla	r5, cy, r8, r5

	subs	n, n, #1

	bne	L(tpu)

L(edu):	str	r5, [rp], #4

	mov	r12, #0

	umaal	r12, cy, r5, d

	mul	r5, r11, r4

	mla	r5, cy, r8, r5

	str	r5, [rp]

	pop	{r10,r11}

	pop	{r4,r5,r6,r7,r8,r9}

	bx	r14

L(edx):	mul	r5, r11, r4

	str	r5, [rp]

	pop	{r10,r11}

	pop	{r4,r5,r6,r7,r8,r9}

	bx	r14

EPILOGUE()