1 // Copyright 2013 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 #if V8_TARGET_ARCH_ARM64
6
7 #include "src/arm64/utils-arm64.h"
8
9
10 namespace v8 {
11 namespace internal {
12
13 #define __ assm->
14
float_sign(float val)15 uint32_t float_sign(float val) {
16 uint32_t bits = bit_cast<uint32_t>(val);
17 return unsigned_bitextract_32(31, 31, bits);
18 }
19
float_exp(float val)20 uint32_t float_exp(float val) {
21 uint32_t bits = bit_cast<uint32_t>(val);
22 return unsigned_bitextract_32(30, 23, bits);
23 }
24
float_mantissa(float val)25 uint32_t float_mantissa(float val) {
26 uint32_t bits = bit_cast<uint32_t>(val);
27 return unsigned_bitextract_32(22, 0, bits);
28 }
29
double_sign(double val)30 uint32_t double_sign(double val) {
31 uint64_t bits = bit_cast<uint64_t>(val);
32 return static_cast<uint32_t>(unsigned_bitextract_64(63, 63, bits));
33 }
34
double_exp(double val)35 uint32_t double_exp(double val) {
36 uint64_t bits = bit_cast<uint64_t>(val);
37 return static_cast<uint32_t>(unsigned_bitextract_64(62, 52, bits));
38 }
39
double_mantissa(double val)40 uint64_t double_mantissa(double val) {
41 uint64_t bits = bit_cast<uint64_t>(val);
42 return unsigned_bitextract_64(51, 0, bits);
43 }
44
float_pack(uint32_t sign,uint32_t exp,uint32_t mantissa)45 float float_pack(uint32_t sign, uint32_t exp, uint32_t mantissa) {
46 uint32_t bits = sign << kFloatExponentBits | exp;
47 return bit_cast<float>((bits << kFloatMantissaBits) | mantissa);
48 }
49
double_pack(uint64_t sign,uint64_t exp,uint64_t mantissa)50 double double_pack(uint64_t sign, uint64_t exp, uint64_t mantissa) {
51 uint64_t bits = sign << kDoubleExponentBits | exp;
52 return bit_cast<double>((bits << kDoubleMantissaBits) | mantissa);
53 }
54
float16classify(float16 value)55 int float16classify(float16 value) {
56 const uint16_t exponent_max = (1 << kFloat16ExponentBits) - 1;
57 const uint16_t exponent_mask = exponent_max << kFloat16MantissaBits;
58 const uint16_t mantissa_mask = (1 << kFloat16MantissaBits) - 1;
59
60 const uint16_t exponent = (value & exponent_mask) >> kFloat16MantissaBits;
61 const uint16_t mantissa = value & mantissa_mask;
62 if (exponent == 0) {
63 if (mantissa == 0) {
64 return FP_ZERO;
65 }
66 return FP_SUBNORMAL;
67 } else if (exponent == exponent_max) {
68 if (mantissa == 0) {
69 return FP_INFINITE;
70 }
71 return FP_NAN;
72 }
73 return FP_NORMAL;
74 }
75
CountLeadingZeros(uint64_t value,int width)76 int CountLeadingZeros(uint64_t value, int width) {
77 DCHECK(base::bits::IsPowerOfTwo(width) && (width <= 64));
78 if (value == 0) {
79 return width;
80 }
81 return base::bits::CountLeadingZeros64(value << (64 - width));
82 }
83
84
CountLeadingSignBits(int64_t value,int width)85 int CountLeadingSignBits(int64_t value, int width) {
86 DCHECK(base::bits::IsPowerOfTwo(width) && (width <= 64));
87 if (value >= 0) {
88 return CountLeadingZeros(value, width) - 1;
89 } else {
90 return CountLeadingZeros(~value, width) - 1;
91 }
92 }
93
94
CountTrailingZeros(uint64_t value,int width)95 int CountTrailingZeros(uint64_t value, int width) {
96 DCHECK((width == 32) || (width == 64));
97 if (width == 64) {
98 return static_cast<int>(base::bits::CountTrailingZeros64(value));
99 }
100 return static_cast<int>(base::bits::CountTrailingZeros32(
101 static_cast<uint32_t>(value & 0xFFFFFFFFF)));
102 }
103
104
CountSetBits(uint64_t value,int width)105 int CountSetBits(uint64_t value, int width) {
106 DCHECK((width == 32) || (width == 64));
107 if (width == 64) {
108 return static_cast<int>(base::bits::CountPopulation(value));
109 }
110 return static_cast<int>(
111 base::bits::CountPopulation(static_cast<uint32_t>(value & 0xFFFFFFFFF)));
112 }
113
LowestSetBitPosition(uint64_t value)114 int LowestSetBitPosition(uint64_t value) {
115 DCHECK_NE(value, 0U);
116 return CountTrailingZeros(value, 64) + 1;
117 }
118
HighestSetBitPosition(uint64_t value)119 int HighestSetBitPosition(uint64_t value) {
120 DCHECK_NE(value, 0U);
121 return 63 - CountLeadingZeros(value, 64);
122 }
123
124
LargestPowerOf2Divisor(uint64_t value)125 uint64_t LargestPowerOf2Divisor(uint64_t value) {
126 return value & -value;
127 }
128
129
MaskToBit(uint64_t mask)130 int MaskToBit(uint64_t mask) {
131 DCHECK_EQ(CountSetBits(mask, 64), 1);
132 return CountTrailingZeros(mask, 64);
133 }
134
135 #undef __
136
137 } // namespace internal
138 } // namespace v8
139
140 #endif // V8_TARGET_ARCH_ARM64
141