drm_fixp_test.c

 1// SPDX-License-Identifier: MIT
 2/*
 3 * Copyright 2022 Advanced Micro Devices, Inc.
 4 */
 5
 6#include <kunit/test.h>
 7#include <drm/drm_fixed.h>
 8
 9static void drm_test_sm2fixp(struct kunit *test)
10{
11	KUNIT_EXPECT_EQ(test, 0x7fffffffffffffffll, ((1ull << 63) - 1));
12
13	/* 1 */
14	KUNIT_EXPECT_EQ(test, drm_int2fixp(1), drm_sm2fixp(1ull << DRM_FIXED_POINT));
15
16	/* -1 */
17	KUNIT_EXPECT_EQ(test, drm_int2fixp(-1),
18			drm_sm2fixp((1ull << 63) | (1ull << DRM_FIXED_POINT)));
19
20	/* 0.5 */
21	KUNIT_EXPECT_EQ(test, drm_fixp_from_fraction(1, 2),
22			drm_sm2fixp(1ull << (DRM_FIXED_POINT - 1)));
23
24	/* -0.5 */
25	KUNIT_EXPECT_EQ(test, drm_fixp_from_fraction(-1, 2),
26			drm_sm2fixp((1ull << 63) | (1ull << (DRM_FIXED_POINT - 1))));
27}
28
29static void drm_test_int2fixp(struct kunit *test)
30{
31	/* 1 */
32	KUNIT_EXPECT_EQ(test, 1ll << 32, drm_int2fixp(1));
33
34	/* -1 */
35	KUNIT_EXPECT_EQ(test, -(1ll << 32), drm_int2fixp(-1));
36
37	/* 1 + (-1) = 0 */
38	KUNIT_EXPECT_EQ(test, 0, drm_int2fixp(1) + drm_int2fixp(-1));
39
40	/* 1 / 2 */
41	KUNIT_EXPECT_EQ(test, 1ll << 31, drm_fixp_from_fraction(1, 2));
42
43	/* -0.5 */
44	KUNIT_EXPECT_EQ(test, -(1ll << 31), drm_fixp_from_fraction(-1, 2));
45
46	/* (1 / 2) + (-1) = 0.5 */
47	KUNIT_EXPECT_EQ(test, 1ll << 31, drm_fixp_from_fraction(-1, 2) + drm_int2fixp(1));
48
49	/* (1 / 2) - 1) = 0.5 */
50	KUNIT_EXPECT_EQ(test, -(1ll << 31), drm_fixp_from_fraction(1, 2) + drm_int2fixp(-1));
51
52	/* (1 / 2) - 1) = 0.5 */
53	KUNIT_EXPECT_EQ(test, -(1ll << 31), drm_fixp_from_fraction(1, 2) - drm_int2fixp(1));
54}
55
56static struct kunit_case drm_fixp_tests[] = {
57	KUNIT_CASE(drm_test_int2fixp),
58	KUNIT_CASE(drm_test_sm2fixp),
59	{ }
60};
61
62static struct kunit_suite drm_fixp_test_suite = {
63	.name = "drm_fixp",
64	.test_cases = drm_fixp_tests,
65};
66
67kunit_test_suite(drm_fixp_test_suite);
68
69MODULE_AUTHOR("AMD");
70MODULE_LICENSE("Dual MIT/GPL");
71MODULE_DESCRIPTION("Unit tests for drm_fixed.h");