dnl  ARM mpn_invert_limb -- Invert a normalized limb.

dnl  Copyright 2001, 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')

ASM_START()
PROLOGUE(mpn_invert_limb)
	LEA(	r2, approx_tab-512)
	mov	r3, r0, lsr #23
	mov	r3, r3, asl #1
	ldrh	r3, [r3, r2]
	mov	r1, r3, asl #17
	mul	r12, r3, r3
	umull	r3, r2, r12, r0
	sub	r1, r1, r2, asl #1
	umull	r3, r2, r1, r1
	umull	r12, r3, r0, r3
	umull	r2, r12, r0, r2
	adds	r2, r2, r3
	adc	r12, r12, #0
	rsb	r1, r12, r1
	mvn	r2, r2, lsr #30
	add	r2, r2, r1, asl #2
	umull	r12, r3, r0, r2
	adds	r1, r12, r0
	adc	r3, r3, r0
	rsb	r0, r3, r2
	bx	lr
EPILOGUE()

	.section .rodata
	ALIGN(2)
approx_tab:
	.short    0xffc0,0xfec0,0xfdc0,0xfcc0,0xfbc0,0xfac0,0xfa00,0xf900
	.short    0xf800,0xf700,0xf640,0xf540,0xf440,0xf380,0xf280,0xf180
	.short    0xf0c0,0xefc0,0xef00,0xee00,0xed40,0xec40,0xeb80,0xeac0
	.short    0xe9c0,0xe900,0xe840,0xe740,0xe680,0xe5c0,0xe500,0xe400
	.short    0xe340,0xe280,0xe1c0,0xe100,0xe040,0xdf80,0xdec0,0xde00
	.short    0xdd40,0xdc80,0xdbc0,0xdb00,0xda40,0xd980,0xd8c0,0xd800
	.short    0xd740,0xd680,0xd600,0xd540,0xd480,0xd3c0,0xd340,0xd280
	.short    0xd1c0,0xd140,0xd080,0xcfc0,0xcf40,0xce80,0xcdc0,0xcd40
	.short    0xcc80,0xcc00,0xcb40,0xcac0,0xca00,0xc980,0xc8c0,0xc840
	.short    0xc780,0xc700,0xc640,0xc5c0,0xc540,0xc480,0xc400,0xc380
	.short    0xc2c0,0xc240,0xc1c0,0xc100,0xc080,0xc000,0xbf80,0xbec0
	.short    0xbe40,0xbdc0,0xbd40,0xbc80,0xbc00,0xbb80,0xbb00,0xba80
	.short    0xba00,0xb980,0xb900,0xb840,0xb7c0,0xb740,0xb6c0,0xb640
	.short    0xb5c0,0xb540,0xb4c0,0xb440,0xb3c0,0xb340,0xb2c0,0xb240
	.short    0xb1c0,0xb140,0xb0c0,0xb080,0xb000,0xaf80,0xaf00,0xae80
	.short    0xae00,0xad80,0xad40,0xacc0,0xac40,0xabc0,0xab40,0xaac0
	.short    0xaa80,0xaa00,0xa980,0xa900,0xa8c0,0xa840,0xa7c0,0xa740
	.short    0xa700,0xa680,0xa600,0xa5c0,0xa540,0xa4c0,0xa480,0xa400
	.short    0xa380,0xa340,0xa2c0,0xa240,0xa200,0xa180,0xa140,0xa0c0
	.short    0xa080,0xa000,0x9f80,0x9f40,0x9ec0,0x9e80,0x9e00,0x9dc0
	.short    0x9d40,0x9d00,0x9c80,0x9c40,0x9bc0,0x9b80,0x9b00,0x9ac0
	.short    0x9a40,0x9a00,0x9980,0x9940,0x98c0,0x9880,0x9840,0x97c0
	.short    0x9780,0x9700,0x96c0,0x9680,0x9600,0x95c0,0x9580,0x9500
	.short    0x94c0,0x9440,0x9400,0x93c0,0x9340,0x9300,0x92c0,0x9240
	.short    0x9200,0x91c0,0x9180,0x9100,0x90c0,0x9080,0x9000,0x8fc0
	.short    0x8f80,0x8f40,0x8ec0,0x8e80,0x8e40,0x8e00,0x8d80,0x8d40
	.short    0x8d00,0x8cc0,0x8c80,0x8c00,0x8bc0,0x8b80,0x8b40,0x8b00
	.short    0x8a80,0x8a40,0x8a00,0x89c0,0x8980,0x8940,0x88c0,0x8880
	.short    0x8840,0x8800,0x87c0,0x8780,0x8740,0x8700,0x8680,0x8640
	.short    0x8600,0x85c0,0x8580,0x8540,0x8500,0x84c0,0x8480,0x8440
	.short    0x8400,0x8380,0x8340,0x8300,0x82c0,0x8280,0x8240,0x8200
	.short    0x81c0,0x8180,0x8140,0x8100,0x80c0,0x8080,0x8040,0x8000
ASM_END()
