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1 // Copyright 2014 the V8 project authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 // Check all examples from table 10-1 of "Hacker's Delight". | |
6 | |
7 #include "src/base/division-by-constant.h" | |
8 | |
9 #include <ostream> // NOLINT | |
10 | |
11 #include "testing/gtest-support.h" | |
12 | |
13 namespace v8 { | |
14 namespace base { | |
15 | |
16 template <class T> | |
17 std::ostream& operator<<(std::ostream& os, | |
18 const MagicNumbersForDivision<T>& mag) { | |
19 return os << "{ multiplier: " << mag.multiplier << ", shift: " << mag.shift | |
20 << ", add: " << mag.add << " }"; | |
21 } | |
22 | |
23 | |
24 // Some abbreviations... | |
25 | |
26 typedef MagicNumbersForDivision<uint32_t> M32; | |
27 typedef MagicNumbersForDivision<uint64_t> M64; | |
28 | |
29 | |
30 static M32 s32(int32_t d) { | |
31 return SignedDivisionByConstant<uint32_t>(static_cast<uint32_t>(d)); | |
32 } | |
33 | |
34 | |
35 static M64 s64(int64_t d) { | |
36 return SignedDivisionByConstant<uint64_t>(static_cast<uint64_t>(d)); | |
37 } | |
38 | |
39 | |
40 static M32 u32(uint32_t d) { return UnsignedDivisionByConstant<uint32_t>(d); } | |
41 static M64 u64(uint64_t d) { return UnsignedDivisionByConstant<uint64_t>(d); } | |
42 | |
43 | |
44 TEST(DivisionByConstant, Signed32) { | |
45 EXPECT_EQ(M32(0x99999999U, 1, false), s32(-5)); | |
46 EXPECT_EQ(M32(0x55555555U, 1, false), s32(-3)); | |
47 int32_t d = -1; | |
48 for (unsigned k = 1; k <= 32 - 1; ++k) { | |
49 d *= 2; | |
50 EXPECT_EQ(M32(0x7FFFFFFFU, k - 1, false), s32(d)); | |
51 } | |
52 for (unsigned k = 1; k <= 32 - 2; ++k) { | |
53 EXPECT_EQ(M32(0x80000001U, k - 1, false), s32(1 << k)); | |
54 } | |
55 EXPECT_EQ(M32(0x55555556U, 0, false), s32(3)); | |
56 EXPECT_EQ(M32(0x66666667U, 1, false), s32(5)); | |
57 EXPECT_EQ(M32(0x2AAAAAABU, 0, false), s32(6)); | |
58 EXPECT_EQ(M32(0x92492493U, 2, false), s32(7)); | |
59 EXPECT_EQ(M32(0x38E38E39U, 1, false), s32(9)); | |
60 EXPECT_EQ(M32(0x66666667U, 2, false), s32(10)); | |
61 EXPECT_EQ(M32(0x2E8BA2E9U, 1, false), s32(11)); | |
62 EXPECT_EQ(M32(0x2AAAAAABU, 1, false), s32(12)); | |
63 EXPECT_EQ(M32(0x51EB851FU, 3, false), s32(25)); | |
64 EXPECT_EQ(M32(0x10624DD3U, 3, false), s32(125)); | |
65 EXPECT_EQ(M32(0x68DB8BADU, 8, false), s32(625)); | |
66 } | |
67 | |
68 | |
69 TEST(DivisionByConstant, Unsigned32) { | |
70 EXPECT_EQ(M32(0x00000000U, 0, true), u32(1)); | |
71 for (unsigned k = 1; k <= 30; ++k) { | |
72 EXPECT_EQ(M32(1U << (32 - k), 0, false), u32(1U << k)); | |
73 } | |
74 EXPECT_EQ(M32(0xAAAAAAABU, 1, false), u32(3)); | |
75 EXPECT_EQ(M32(0xCCCCCCCDU, 2, false), u32(5)); | |
76 EXPECT_EQ(M32(0xAAAAAAABU, 2, false), u32(6)); | |
77 EXPECT_EQ(M32(0x24924925U, 3, true), u32(7)); | |
78 EXPECT_EQ(M32(0x38E38E39U, 1, false), u32(9)); | |
79 EXPECT_EQ(M32(0xCCCCCCCDU, 3, false), u32(10)); | |
80 EXPECT_EQ(M32(0xBA2E8BA3U, 3, false), u32(11)); | |
81 EXPECT_EQ(M32(0xAAAAAAABU, 3, false), u32(12)); | |
82 EXPECT_EQ(M32(0x51EB851FU, 3, false), u32(25)); | |
83 EXPECT_EQ(M32(0x10624DD3U, 3, false), u32(125)); | |
84 EXPECT_EQ(M32(0xD1B71759U, 9, false), u32(625)); | |
85 } | |
86 | |
87 | |
88 TEST(DivisionByConstant, Signed64) { | |
89 EXPECT_EQ(M64(0x9999999999999999ULL, 1, false), s64(-5)); | |
90 EXPECT_EQ(M64(0x5555555555555555ULL, 1, false), s64(-3)); | |
91 int64_t d = -1; | |
92 for (unsigned k = 1; k <= 64 - 1; ++k) { | |
93 d *= 2; | |
94 EXPECT_EQ(M64(0x7FFFFFFFFFFFFFFFULL, k - 1, false), s64(d)); | |
95 } | |
96 for (unsigned k = 1; k <= 64 - 2; ++k) { | |
97 EXPECT_EQ(M64(0x8000000000000001ULL, k - 1, false), s64(1LL << k)); | |
98 } | |
99 EXPECT_EQ(M64(0x5555555555555556ULL, 0, false), s64(3)); | |
100 EXPECT_EQ(M64(0x6666666666666667ULL, 1, false), s64(5)); | |
101 EXPECT_EQ(M64(0x2AAAAAAAAAAAAAABULL, 0, false), s64(6)); | |
102 EXPECT_EQ(M64(0x4924924924924925ULL, 1, false), s64(7)); | |
103 EXPECT_EQ(M64(0x1C71C71C71C71C72ULL, 0, false), s64(9)); | |
104 EXPECT_EQ(M64(0x6666666666666667ULL, 2, false), s64(10)); | |
105 EXPECT_EQ(M64(0x2E8BA2E8BA2E8BA3ULL, 1, false), s64(11)); | |
106 EXPECT_EQ(M64(0x2AAAAAAAAAAAAAABULL, 1, false), s64(12)); | |
107 EXPECT_EQ(M64(0xA3D70A3D70A3D70BULL, 4, false), s64(25)); | |
108 EXPECT_EQ(M64(0x20C49BA5E353F7CFULL, 4, false), s64(125)); | |
109 EXPECT_EQ(M64(0x346DC5D63886594BULL, 7, false), s64(625)); | |
110 } | |
111 | |
112 | |
113 TEST(DivisionByConstant, Unsigned64) { | |
114 EXPECT_EQ(M64(0x0000000000000000ULL, 0, true), u64(1)); | |
115 for (unsigned k = 1; k <= 64 - 2; ++k) { | |
116 EXPECT_EQ(M64(1ULL << (64 - k), 0, false), u64(1ULL << k)); | |
117 } | |
118 EXPECT_EQ(M64(0xAAAAAAAAAAAAAAABULL, 1, false), u64(3)); | |
119 EXPECT_EQ(M64(0xCCCCCCCCCCCCCCCDULL, 2, false), u64(5)); | |
120 EXPECT_EQ(M64(0xAAAAAAAAAAAAAAABULL, 2, false), u64(6)); | |
121 EXPECT_EQ(M64(0x2492492492492493ULL, 3, true), u64(7)); | |
122 EXPECT_EQ(M64(0xE38E38E38E38E38FULL, 3, false), u64(9)); | |
123 EXPECT_EQ(M64(0xCCCCCCCCCCCCCCCDULL, 3, false), u64(10)); | |
124 EXPECT_EQ(M64(0x2E8BA2E8BA2E8BA3ULL, 1, false), u64(11)); | |
125 EXPECT_EQ(M64(0xAAAAAAAAAAAAAAABULL, 3, false), u64(12)); | |
126 EXPECT_EQ(M64(0x47AE147AE147AE15ULL, 5, true), u64(25)); | |
127 EXPECT_EQ(M64(0x0624DD2F1A9FBE77ULL, 7, true), u64(125)); | |
128 EXPECT_EQ(M64(0x346DC5D63886594BULL, 7, false), u64(625)); | |
129 } | |
130 | |
131 } // namespace base | |
132 } // namespace v8 | |
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