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1 /* | 1 /* |
2 * Copyright (c) 2012, Google Inc. All rights reserved. | 2 * Copyright (c) 2012, Google Inc. All rights reserved. |
3 * | 3 * |
4 * Redistribution and use in source and binary forms, with or without | 4 * Redistribution and use in source and binary forms, with or without |
5 * modification, are permitted provided that the following conditions are | 5 * modification, are permitted provided that the following conditions are |
6 * met: | 6 * met: |
7 * | 7 * |
8 * * Redistributions of source code must retain the above copyright | 8 * * Redistributions of source code must retain the above copyright |
9 * notice, this list of conditions and the following disclaimer. | 9 * notice, this list of conditions and the following disclaimer. |
10 * * Redistributions in binary form must reproduce the above | 10 * * Redistributions in binary form must reproduce the above |
(...skipping 13 matching lines...) Expand all Loading... | |
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
29 */ | 29 */ |
30 | 30 |
31 #ifndef SaturatedArithmetic_h | 31 #ifndef SaturatedArithmetic_h |
32 #define SaturatedArithmetic_h | 32 #define SaturatedArithmetic_h |
33 | 33 |
34 #include "wtf/CPU.h" | |
34 #include <limits> | 35 #include <limits> |
35 #include <stdint.h> | 36 #include <stdint.h> |
36 | 37 |
38 #if CPU(ARM_TRADITIONAL) && COMPILER(GCC) | |
39 | |
40 // If we're building ARM on GCC we replace the C++ versions with some | |
41 // native arm assembly for speed. | |
42 #include "wtf/asm/SaturatedArithmeticAsm.h" | |
eseidel
2014/06/20 16:30:20
I probably would have called it wtf/SaturatedArith
picksi
2014/06/23 15:30:43
Done.
| |
43 | |
44 #else | |
45 | |
37 ALWAYS_INLINE int32_t saturatedAddition(int32_t a, int32_t b) | 46 ALWAYS_INLINE int32_t saturatedAddition(int32_t a, int32_t b) |
38 { | 47 { |
39 uint32_t ua = a; | 48 uint32_t ua = a; |
40 uint32_t ub = b; | 49 uint32_t ub = b; |
41 uint32_t result = ua + ub; | 50 uint32_t result = ua + ub; |
42 | 51 |
43 // Can only overflow if the signed bit of the two values match. If the signe d | 52 // Can only overflow if the signed bit of the two values match. If the |
44 // bit of the result and one of the values differ it did overflow. | 53 // signed bit of the result and one of the values differ it overflowed. |
45 if (!((ua ^ ub) >> 31) & (result ^ ua) >> 31) | 54 |
55 if (~(ua ^ ub) & (result ^ ua) & (1 << 31)) { | |
46 result = std::numeric_limits<int>::max() + (ua >> 31); | 56 result = std::numeric_limits<int>::max() + (ua >> 31); |
Stephen Chennney
2014/06/20 14:46:56
No braces and immediately "return std::num..."
picksi
2014/06/23 15:30:43
Done.
| |
57 } | |
47 | 58 |
48 return result; | 59 return result; |
49 } | 60 } |
50 | 61 |
51 ALWAYS_INLINE int32_t saturatedSubtraction(int32_t a, int32_t b) | 62 ALWAYS_INLINE int32_t saturatedSubtraction(int32_t a, int32_t b) |
52 { | 63 { |
53 uint32_t ua = a; | 64 uint32_t ua = a; |
54 uint32_t ub = b; | 65 uint32_t ub = b; |
55 uint32_t result = ua - ub; | 66 uint32_t result = ua - ub; |
56 | 67 |
57 // Can only overflow if the signed bit of the two values do not match. If th e | 68 // Can only overflow if the signed bit of the two input values differ. If |
58 // signed bit of the result and the first value differ it did overflow. | 69 // the signed bit of the result and the first value differ it overflowed. |
59 if ((ua ^ ub) >> 31 & (result ^ ua) >> 31) | 70 |
71 if ((ua ^ ub) & (result ^ ua) & (1 << 31)) { | |
60 result = std::numeric_limits<int>::max() + (ua >> 31); | 72 result = std::numeric_limits<int>::max() + (ua >> 31); |
Stephen Chennney
2014/06/20 14:46:56
Ditto.
picksi
2014/06/23 15:30:43
Done.
| |
73 } | |
61 | 74 |
62 return result; | 75 return result; |
63 } | 76 } |
64 | 77 |
78 inline int getMaxSaturatedSetResultForTesting(int FractionalShift) | |
79 { | |
80 // For C version the set function maxes out to max int, this differs from | |
81 // the ARM asm version, see SaturatedArithmetiAsm.h for the equivlent asm | |
82 // version. | |
83 return std::numeric_limits<int>::max(); | |
84 } | |
85 | |
86 inline int getMinSaturatedSetResultForTesting(int FractionalShift) | |
87 { | |
88 return std::numeric_limits<int>::min(); | |
89 } | |
90 | |
91 ALWAYS_INLINE int saturatedSet(int value, int FractionalShift) | |
92 { | |
93 const int intMaxForLayoutUnit = | |
94 std::numeric_limits<int>::max() >> FractionalShift; | |
95 | |
96 const int intMinForLayoutUnit = | |
97 std::numeric_limits<int>::min() >> FractionalShift; | |
98 | |
99 if (value >= intMaxForLayoutUnit) { | |
100 return std::numeric_limits<int>::max(); | |
101 } | |
Stephen Chennney
2014/06/20 14:46:56
No braces on single line statements in Blink.
picksi
2014/06/23 15:30:43
Done.
| |
102 | |
103 if (value <= intMinForLayoutUnit) { | |
104 return std::numeric_limits<int>::min(); | |
105 } | |
Stephen Chennney
2014/06/20 14:46:56
Ditto.
picksi
2014/06/23 15:30:43
Done.
| |
106 | |
107 return value << FractionalShift; | |
108 } | |
109 | |
110 | |
111 ALWAYS_INLINE int saturatedSet(unsigned value, int FractionalShift) | |
112 { | |
113 const unsigned intMaxForLayoutUnit = | |
114 std::numeric_limits<int>::max() >> FractionalShift; | |
115 | |
116 if (value >= intMaxForLayoutUnit) { | |
117 return std::numeric_limits<int>::max(); | |
118 } | |
Stephen Chennney
2014/06/20 14:46:56
Ditto,
picksi
2014/06/23 15:30:43
Done.
| |
119 | |
120 return value << FractionalShift; | |
121 } | |
122 | |
123 #endif // CPU(ARM_TRADITIONAL) && COMPILER(GCC) | |
65 #endif // SaturatedArithmetic_h | 124 #endif // SaturatedArithmetic_h |
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