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a6f2f435 | 1 | /* mpn_add_n -- add (or subtract) bignums. |
d614a753 | 2 | Copyright (C) 2013-2020 Free Software Foundation, Inc. |
a6f2f435 RH |
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 | |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
a6f2f435 RH |
18 | |
19 | #include <sysdep.h> | |
ccffb2a2 | 20 | #include <arm-features.h> |
a6f2f435 RH |
21 | |
22 | .syntax unified | |
23 | .text | |
24 | ||
25 | #ifdef USE_AS_SUB_N | |
26 | # define INITC cmp r0, r0 | |
27 | # define OPC sbcs | |
28 | # define RETC sbc r0, r0, r0; neg r0, r0 | |
29 | # define FUNC __mpn_sub_n | |
30 | #else | |
31 | # define INITC cmn r0, #0 | |
32 | # define OPC adcs | |
33 | # define RETC mov r0, #0; adc r0, r0, r0 | |
34 | # define FUNC __mpn_add_n | |
35 | #endif | |
36 | ||
37 | /* mp_limb_t mpn_add_n(res_ptr, src1_ptr, src2_ptr, size) */ | |
38 | ||
39 | ENTRY (FUNC) | |
40 | push { r4, r5, r6, r7, r8, r10, lr } | |
41 | cfi_adjust_cfa_offset (28) | |
42 | cfi_rel_offset (r4, 0) | |
43 | cfi_rel_offset (r5, 4) | |
44 | cfi_rel_offset (r6, 8) | |
45 | cfi_rel_offset (r7, 12) | |
46 | cfi_rel_offset (r8, 16) | |
47 | cfi_rel_offset (r10, 20) | |
48 | cfi_rel_offset (lr, 24) | |
49 | ||
50 | INITC /* initialize carry flag */ | |
51 | tst r3, #1 /* count & 1 == 1? */ | |
52 | add lr, r1, r3, lsl #2 /* compute end src1 */ | |
53 | beq 1f | |
54 | ||
81cb7a0b ZW |
55 | ldr r4, [r1], #4 /* do one to make count even */ |
56 | ldr r5, [r2], #4 | |
a6f2f435 RH |
57 | OPC r4, r4, r5 |
58 | teq r1, lr /* end of count? (preserve carry) */ | |
81cb7a0b | 59 | str r4, [r0], #4 |
a6f2f435 RH |
60 | beq 9f |
61 | 1: | |
62 | tst r3, #2 /* count & 2 == 2? */ | |
63 | beq 2f | |
81cb7a0b ZW |
64 | ldm r1!, { r4, r5 } /* do two to make count 0 mod 4 */ |
65 | ldm r2!, { r6, r7 } | |
a6f2f435 RH |
66 | OPC r4, r4, r6 |
67 | OPC r5, r5, r7 | |
68 | teq r1, lr /* end of count? */ | |
81cb7a0b | 69 | stm r0!, { r4, r5 } |
a6f2f435 RH |
70 | beq 9f |
71 | 2: | |
81cb7a0b ZW |
72 | ldm r1!, { r3, r5, r7, r10 } /* do four each loop */ |
73 | ldm r2!, { r4, r6, r8, ip } | |
a6f2f435 RH |
74 | OPC r3, r3, r4 |
75 | OPC r5, r5, r6 | |
76 | OPC r7, r7, r8 | |
77 | OPC r10, r10, ip | |
78 | teq r1, lr | |
81cb7a0b | 79 | stm r0!, { r3, r5, r7, r10 } |
a6f2f435 RH |
80 | bne 2b |
81 | ||
82 | 9: | |
83 | RETC /* copy carry out */ | |
ccffb2a2 | 84 | #ifndef ARM_ALWAYS_BX |
a6f2f435 | 85 | pop { r4, r5, r6, r7, r8, r10, pc } |
ccffb2a2 RM |
86 | #else |
87 | pop { r4, r5, r6, r7, r8, r10, lr } | |
88 | bx lr | |
89 | #endif | |
a6f2f435 | 90 | END (FUNC) |