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feeeff5c | 1 | /* Generic unsigned 32 bit modulo implementation. |
a5544970 | 2 | Copyright (C) 2009-2019 Free Software Foundation, Inc. |
feeeff5c JR |
3 | Contributed by Embecosm on behalf of Adapteva, Inc. |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | This file is free software; you can redistribute it and/or modify it | |
8 | under the terms of the GNU General Public License as published by the | |
9 | Free Software Foundation; either version 3, or (at your option) any | |
10 | later version. | |
11 | ||
12 | This file is distributed in the hope that it will be useful, but | |
13 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | General Public License for more details. | |
16 | ||
17 | Under Section 7 of GPL version 3, you are granted additional | |
18 | permissions described in the GCC Runtime Library Exception, version | |
19 | 3.1, as published by the Free Software Foundation. | |
20 | ||
21 | You should have received a copy of the GNU General Public License and | |
22 | a copy of the GCC Runtime Library Exception along with this program; | |
23 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
24 | <http://www.gnu.org/licenses/>. */ | |
25 | ||
26 | typedef union { unsigned int i; float f; } fu; | |
27 | ||
28 | unsigned int __umodsi3 (unsigned int a, unsigned int b); | |
29 | ||
30 | unsigned int | |
31 | __umodsi3 (unsigned int a, unsigned int b) | |
32 | { | |
33 | unsigned int d, t, s0, s1, s2, r0, r1; | |
34 | fu u0, u1, u2, u1b, u2b; | |
35 | ||
36 | if (b > a) | |
37 | return a; | |
38 | ||
39 | /* Compute difference in number of bits in S0. */ | |
40 | u0.i = 0x40000000; | |
41 | u1b.i = u2b.i = u0.i; | |
42 | u1.i = a; | |
43 | u2.i = b; | |
44 | u1.i = a | u0.i; | |
45 | t = 0x4b800000 | ((a >> 23) & 0xffff); | |
46 | if (a >> 23) | |
47 | { | |
48 | u1.i = t; | |
49 | u1b.i = 0x4b800000; | |
50 | } | |
51 | u2.i = b | u0.i; | |
52 | t = 0x4b800000 | ((b >> 23) & 0xffff); | |
53 | if (b >> 23) | |
54 | { | |
55 | u2.i = t; | |
56 | u2b.i = 0x4b800000; | |
57 | } | |
58 | u1.f = u1.f - u1b.f; | |
59 | u2.f = u2.f - u2b.f; | |
60 | s1 = u1.i >> 23; | |
61 | s2 = u2.i >> 23; | |
62 | s0 = s1 - s2; | |
63 | ||
64 | #define STEP(n) case n: d = b << n; t = a - d; if (t <= a) a = t; | |
65 | switch (s0) | |
66 | { | |
67 | STEP (31) | |
68 | STEP (30) | |
69 | STEP (29) | |
70 | STEP (28) | |
71 | STEP (27) | |
72 | STEP (26) | |
73 | STEP (25) | |
74 | STEP (24) | |
75 | STEP (23) | |
76 | STEP (22) | |
77 | STEP (21) | |
78 | STEP (20) | |
79 | STEP (19) | |
80 | STEP (18) | |
81 | STEP (17) | |
82 | STEP (16) | |
83 | STEP (15) | |
84 | STEP (14) | |
85 | STEP (13) | |
86 | STEP (12) | |
87 | STEP (11) | |
88 | STEP (10) | |
89 | STEP (9) | |
90 | STEP (8) | |
91 | STEP (7) | |
92 | STEP (6) | |
93 | STEP (5) | |
94 | STEP (4) | |
95 | STEP (3) | |
96 | STEP (2) | |
97 | STEP (1) | |
98 | STEP (0) | |
99 | } | |
100 | return a; | |
101 | } |