1/*-------------------------------------------------------------------------
2 * drawElements Base Portability Library
3 * -------------------------------------
4 *
5 * Copyright 2015 The Android Open Source Project
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 *      http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 *
19 *//*!
20 * \file
21 * \brief Testing of deMath functions.
22 *//*--------------------------------------------------------------------*/
23
24#include "deMath.h"
25#include "deRandom.h"
26
27DE_BEGIN_EXTERN_C
28
29static deBool conversionToFloatLosesPrecision (deInt32 x)
30{
31	if (x == -0x7FFFFFFF - 1)
32		return DE_FALSE;
33	else if (x < 0)
34		return conversionToFloatLosesPrecision(-x);
35	else if (x == 0)
36		return DE_FALSE;
37	else if (((deUint32)x & 0x1) == 0)
38		return conversionToFloatLosesPrecision(x >> 1); /* remove trailing zeros */
39	else
40		return x > ((1 << 24) - 1); /* remaining part does not fit in the mantissa? */
41}
42
43static void testSingleInt32ToFloat (deInt32 x)
44{
45	/* roundTowardsToNegInf(x) <= round(x) <= roundTowardsPosInf(x). */
46	/* \note: Need to use inequalities since round(x) returns arbitrary precision floats. */
47	DE_TEST_ASSERT(deInt32ToFloatRoundToNegInf(x) <= deInt32ToFloat(x));
48	DE_TEST_ASSERT(deInt32ToFloat(x) <= deInt32ToFloatRoundToPosInf(x));
49
50	/* if precision is lost, floor(x) < ceil(x). Else floor(x) == ceil(x) */
51	if (conversionToFloatLosesPrecision(x))
52		DE_TEST_ASSERT(deInt32ToFloatRoundToNegInf(x) < deInt32ToFloatRoundToPosInf(x));
53	else
54		DE_TEST_ASSERT(deInt32ToFloatRoundToNegInf(x) == deInt32ToFloatRoundToPosInf(x));
55
56	/* max one ulp from each other */
57	if (deInt32ToFloatRoundToNegInf(x) < deInt32ToFloatRoundToPosInf(x))
58	{
59		union
60		{
61			float f;
62			deInt32 u;
63		} v0, v1;
64
65		v0.f = deInt32ToFloatRoundToNegInf(x);
66		v1.f = deInt32ToFloatRoundToPosInf(x);
67
68		DE_TEST_ASSERT(v0.u + 1 == v1.u || v0.u == v1.u + 1);
69	}
70}
71
72static void testInt32ToFloat (void)
73{
74	const int	numIterations = 2500000;
75
76	int			sign;
77	int			numBits;
78	int			delta;
79	int			ndx;
80	deRandom	rnd;
81
82	deRandom_init(&rnd, 0xdeadbeefu-1);
83
84	for (sign = -1; sign < 1; ++sign)
85	for (numBits = 0; numBits < 32; ++numBits)
86	for (delta = -2; delta < 3; ++delta)
87	{
88		const deInt64 x = (deInt64)(sign == -1 ? (-1) : (+1)) * (1LL << (deInt64)numBits) + (deInt64)delta;
89
90		/* would overflow */
91		if (x > 0x7FFFFFFF || x < -0x7FFFFFFF - 1)
92			continue;
93
94		testSingleInt32ToFloat((deInt32)x);
95	}
96
97	for (ndx = 0; ndx < numIterations; ++ndx)
98		testSingleInt32ToFloat((deInt32)deRandom_getUint32(&rnd));
99}
100
101void deMath_selfTest (void)
102{
103	/* Test Int32ToFloat*(). */
104	testInt32ToFloat();
105}
106
107DE_END_EXTERN_C
108