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