1 // SPDX-License-Identifier: GPL-2.0+ 1 // SPDX-License-Identifier: GPL-2.0+
2 2
3 #include <linux/errno.h> 3 #include <linux/errno.h>
4 4
5 #include "test_fpu.h" 5 #include "test_fpu.h"
6 6
7 int test_fpu(void) 7 int test_fpu(void)
8 { 8 {
9 /* 9 /*
10 * This sequence of operations tests t 10 * This sequence of operations tests that rounding mode is
11 * to nearest and that denormal number 11 * to nearest and that denormal numbers are supported.
12 * Volatile variables are used to avoi 12 * Volatile variables are used to avoid compiler optimizing
13 * the calculations away. 13 * the calculations away.
14 */ 14 */
15 volatile double a, b, c, d, e, f, g; 15 volatile double a, b, c, d, e, f, g;
16 16
17 a = 4.0; 17 a = 4.0;
18 b = 1e-15; 18 b = 1e-15;
19 c = 1e-310; 19 c = 1e-310;
20 20
21 /* Sets precision flag */ 21 /* Sets precision flag */
22 d = a + b; 22 d = a + b;
23 23
24 /* Result depends on rounding mode */ 24 /* Result depends on rounding mode */
25 e = a + b / 2; 25 e = a + b / 2;
26 26
27 /* Denormal and very large values */ 27 /* Denormal and very large values */
28 f = b / c; 28 f = b / c;
29 29
30 /* Depends on denormal support */ 30 /* Depends on denormal support */
31 g = a + c * f; 31 g = a + c * f;
32 32
33 if (d > a && e > a && g > a) 33 if (d > a && e > a && g > a)
34 return 0; 34 return 0;
35 else 35 else
36 return -EINVAL; 36 return -EINVAL;
37 } 37 }
38 38
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