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1 | /* Add two limb vectors of equal, non-zero length for PowerPC. | |
2 | Copyright (C) 1997-2019 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, see | |
17 | <https://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <sysdep.h> | |
20 | ||
21 | /* mp_limb_t mpn_add_n (mp_ptr res_ptr, mp_srcptr s1_ptr, mp_srcptr s2_ptr, | |
22 | mp_size_t size) | |
23 | Calculate s1+s2 and put result in res_ptr; return carry, 0 or 1. */ | |
24 | ||
25 | /* Note on optimisation: This code is optimal for the 601. Almost every other | |
26 | possible 2-unrolled inner loop will not be. Also, watch out for the | |
27 | alignment... */ | |
28 | ||
29 | EALIGN (__mpn_add_n, 3, 0) | |
30 | ||
31 | /* Set up for loop below. */ | |
32 | mtcrf 0x01,r6 | |
33 | srwi. r7,r6,1 | |
34 | li r10,0 | |
35 | mtctr r7 | |
36 | bt 31,L(2) | |
37 | ||
38 | /* Clear the carry. */ | |
39 | addic r0,r0,0 | |
40 | /* Adjust pointers for loop. */ | |
41 | addi r3,r3,-4 | |
42 | addi r4,r4,-4 | |
43 | addi r5,r5,-4 | |
44 | b L(0) | |
45 | ||
46 | L(2): lwz r7,0(r5) | |
47 | lwz r6,0(r4) | |
48 | addc r6,r6,r7 | |
49 | stw r6,0(r3) | |
50 | beq L(1) | |
51 | ||
52 | /* The loop. */ | |
53 | ||
54 | /* Align start of loop to an odd word boundary to guarantee that the | |
55 | last two words can be fetched in one access (for 601). */ | |
56 | L(0): lwz r9,4(r4) | |
57 | lwz r8,4(r5) | |
58 | lwzu r6,8(r4) | |
59 | lwzu r7,8(r5) | |
60 | adde r8,r9,r8 | |
61 | stw r8,4(r3) | |
62 | adde r6,r6,r7 | |
63 | stwu r6,8(r3) | |
64 | bdnz L(0) | |
65 | /* Return the carry. */ | |
66 | L(1): addze r3,r10 | |
67 | blr | |
68 | END (__mpn_add_n) |