1/* Add two limb vectors of equal, non-zero length for PowerPC.
2   Copyright (C) 1997, 1999, 2000 Free Software Foundation, Inc.
3   This file is part of the GNU C Library.
4
5   The GNU C Library is free software; you can redistribute it and/or
6   modify it under the terms of the GNU Lesser General Public
7   License as published by the Free Software Foundation; either
8   version 2.1 of the License, or (at your option) any later version.
9
10   The GNU C Library is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   Lesser General Public License for more details.
14
15   You should have received a copy of the GNU Lesser General Public
16   License along with the GNU C Library; if not, write to the Free
17   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18   02111-1307 USA.  */
19
20#include <sysdep.h>
21#include <bp-sym.h>
22#include <bp-asm.h>
23
24/* mp_limb_t mpn_add_n (mp_ptr res_ptr, mp_srcptr s1_ptr, mp_srcptr s2_ptr,
25                        mp_size_t size)
26   Calculate s1+s2 and put result in res_ptr; return carry, 0 or 1.  */
27
28/* Note on optimisation: This code is optimal for the 601.  Almost every other
29   possible 2-unrolled inner loop will not be.  Also, watch out for the
30   alignment...  */
31
32EALIGN (BP_SYM (__mpn_add_n), 3, 0)
33
34#if __BOUNDED_POINTERS__
35	slwi r10,r6,2		/* convert limbs to bytes */
36	CHECK_BOUNDS_BOTH_WIDE (r3, r8, r9, r10)
37	CHECK_BOUNDS_BOTH_WIDE (r4, r8, r9, r10)
38	CHECK_BOUNDS_BOTH_WIDE (r5, r8, r9, r10)
39#endif
40/* Set up for loop below.  */
41	mtcrf 0x01,r6
42	srwi. r7,r6,1
43	li    r10,0
44	mtctr r7
45	bt    31,L(2)
46
47/* Clear the carry.  */
48	addic r0,r0,0
49/* Adjust pointers for loop.  */
50	addi  r3,r3,-4
51	addi  r4,r4,-4
52	addi  r5,r5,-4
53	b     L(0)
54
55L(2):	lwz  r7,0(r5)
56	lwz  r6,0(r4)
57	addc r6,r6,r7
58	stw  r6,0(r3)
59        beq  L(1)
60
61/* The loop.  */
62
63/* Align start of loop to an odd word boundary to guarantee that the
64   last two words can be fetched in one access (for 601).  */
65L(0):	lwz  r9,4(r4)
66	lwz  r8,4(r5)
67	lwzu r6,8(r4)
68	lwzu r7,8(r5)
69	adde r8,r9,r8
70	stw  r8,4(r3)
71	adde r6,r6,r7
72	stwu r6,8(r3)
73	bdnz L(0)
74/* Return the carry.  */
75L(1):	addze r3,r10
76	blr
77END (BP_SYM (__mpn_add_n))
78