projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 9a0a462c | 1 | /* Subtract two limb vectors of equal, non-zero length for PowerPC. |
| f7a9f785 | 2 | Copyright (C) 1997-2016 Free Software Foundation, Inc. |
| 9a0a462c UD |
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 | |
| 41bdb6e2 AJ |
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. | |
| 9a0a462c UD |
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 | |
| 41bdb6e2 | 13 | Lesser General Public License for more details. |
| 9a0a462c | 14 | |
| 41bdb6e2 | 15 | You should have received a copy of the GNU Lesser General Public |
| 59ba27a6 PE |
16 | License along with the GNU C Library; if not, see |
| 17 | <http://www.gnu.org/licenses/>. */ | |
| 9a0a462c UD |
18 | |
| 19 | #include <sysdep.h> | |
| 20 | ||
| 21 | /* mp_limb_t mpn_sub_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 borrow, 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 | ||
| b5510883 | 29 | EALIGN (__mpn_sub_n, 3, 1) |
| fa87f403 | 30 | |
| 9a0a462c | 31 | /* Set up for loop below. */ |
| 217eb19b UD |
32 | mtcrf 0x01,r6 |
| 33 | srwi. r7,r6,1 | |
| 34 | mtctr r7 | |
| 4e141d64 | 35 | bt 31,L(2) |
| 9a0a462c UD |
36 | |
| 37 | /* Set the carry (clear the borrow). */ | |
| 217eb19b | 38 | subfc r0,r0,r0 |
| 9a0a462c | 39 | /* Adjust pointers for loop. */ |
| 217eb19b UD |
40 | addi r3,r3,-4 |
| 41 | addi r4,r4,-4 | |
| 42 | addi r5,r5,-4 | |
| 4e141d64 | 43 | b L(0) |
| 9a0a462c | 44 | |
| 4e141d64 | 45 | L(2): lwz r7,0(r5) |
| 217eb19b UD |
46 | lwz r6,0(r4) |
| 47 | subfc r6,r7,r6 | |
| 48 | stw r6,0(r3) | |
| 4e141d64 | 49 | beq L(1) |
| 9a0a462c UD |
50 | |
| 51 | /* Align start of loop to an odd word boundary to guarantee that the | |
| 52 | last two words can be fetched in one access (for 601). This turns | |
| 53 | out to be important. */ | |
| 4e141d64 | 54 | L(0): |
| 217eb19b UD |
55 | lwz r9,4(r4) |
| 56 | lwz r8,4(r5) | |
| 57 | lwzu r6,8(r4) | |
| 58 | lwzu r7,8(r5) | |
| 59 | subfe r8,r8,r9 | |
| 60 | stw r8,4(r3) | |
| 61 | subfe r6,r7,r6 | |
| 62 | stwu r6,8(r3) | |
| 4e141d64 | 63 | bdnz L(0) |
| 9a0a462c | 64 | /* Return the borrow. */ |
| 4e141d64 | 65 | L(1): subfe r3,r3,r3 |
| 217eb19b | 66 | neg r3,r3 |
| 9a0a462c | 67 | blr |
| b5510883 | 68 | END (__mpn_sub_n) |