xref: /netbsd-src/external/lgpl3/gmp/dist/mpn/arm/rshift.asm (revision 41f3ac3e09f0c1c4d8b911b4c8a1d6450bd14f46)
1dnl  ARM mpn_rshift.
2
3dnl  Contributed to the GNU project by Torbjörn Granlund.
4
5dnl  Copyright 1997, 2000, 2001, 2012 Free Software Foundation, Inc.
6
7dnl  This file is part of the GNU MP Library.
8dnl
9dnl  The GNU MP Library is free software; you can redistribute it and/or modify
10dnl  it under the terms of either:
11dnl
12dnl    * the GNU Lesser General Public License as published by the Free
13dnl      Software Foundation; either version 3 of the License, or (at your
14dnl      option) any later version.
15dnl
16dnl  or
17dnl
18dnl    * the GNU General Public License as published by the Free Software
19dnl      Foundation; either version 2 of the License, or (at your option) any
20dnl      later version.
21dnl
22dnl  or both in parallel, as here.
23dnl
24dnl  The GNU MP Library is distributed in the hope that it will be useful, but
25dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
26dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
27dnl  for more details.
28dnl
29dnl  You should have received copies of the GNU General Public License and the
30dnl  GNU Lesser General Public License along with the GNU MP Library.  If not,
31dnl  see https://www.gnu.org/licenses/.
32
33include(`../config.m4')
34
35C	     cycles/limb
36C StrongARM	 ?
37C XScale	 ?
38C Cortex-A7	 ?
39C Cortex-A8	 ?
40C Cortex-A9	 3.5
41C Cortex-A15	 ?
42
43define(`rp',  `r0')
44define(`up',  `r1')
45define(`n',   `r2')
46define(`cnt', `r3')
47define(`tnc', `r12')
48
49ASM_START()
50PROLOGUE(mpn_rshift)
51	push	{r4, r6, r7, r8}
52	ldr	r4, [up]
53	rsb	tnc, cnt, #32
54
55	mov	r7, r4, lsr cnt
56	tst	n, #1
57	beq	L(evn)			C n even
58
59L(odd):	subs	n, n, #2
60	bcc	L(1)			C n = 1
61	ldr	r8, [up, #4]!
62	b	L(mid)
63
64L(evn):	ldr	r6, [up, #4]!
65	subs	n, n, #2
66	beq	L(end)
67
68L(top):	ldr	r8, [up, #4]!
69	orr	r7, r7, r6, lsl tnc
70	str	r7, [rp], #4
71	mov	r7, r6, lsr cnt
72L(mid):	ldr	r6, [up, #4]!
73	orr	r7, r7, r8, lsl tnc
74	str	r7, [rp], #4
75	mov	r7, r8, lsr cnt
76	subs	n, n, #2
77	bgt	L(top)
78
79L(end):	orr	r7, r7, r6, lsl tnc
80	str	r7, [rp], #4
81	mov	r7, r6, lsr cnt
82L(1):	str	r7, [rp]
83	mov	r0, r4, lsl tnc
84	pop	{r4, r6, r7, r8}
85	return	r14
86EPILOGUE()
87