1 //===-- InstructionUtils.h --------------------------------------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #ifndef lldb_InstructionUtils_h_
11 #define lldb_InstructionUtils_h_
12
13 // Common utilities for manipulating instruction bit fields.
14
15 namespace lldb_private {
16
17 // Return the bit field(s) from the most significant bit (msbit) to the
18 // least significant bit (lsbit) of a 64-bit unsigned value.
19 static inline uint64_t
Bits64(const uint64_t bits,const uint32_t msbit,const uint32_t lsbit)20 Bits64 (const uint64_t bits, const uint32_t msbit, const uint32_t lsbit)
21 {
22 assert(msbit < 64 && lsbit <= msbit);
23 return (bits >> lsbit) & ((1u << (msbit - lsbit + 1)) - 1);
24 }
25
26 // Return the bit field(s) from the most significant bit (msbit) to the
27 // least significant bit (lsbit) of a 32-bit unsigned value.
28 static inline uint32_t
Bits32(const uint32_t bits,const uint32_t msbit,const uint32_t lsbit)29 Bits32 (const uint32_t bits, const uint32_t msbit, const uint32_t lsbit)
30 {
31 assert(msbit < 32 && lsbit <= msbit);
32 return (bits >> lsbit) & ((1u << (msbit - lsbit + 1)) - 1);
33 }
34
35 // Return the bit value from the 'bit' position of a 32-bit unsigned value.
36 static inline uint32_t
Bit32(const uint32_t bits,const uint32_t bit)37 Bit32 (const uint32_t bits, const uint32_t bit)
38 {
39 return (bits >> bit) & 1u;
40 }
41
42 static inline uint64_t
Bit64(const uint64_t bits,const uint32_t bit)43 Bit64 (const uint64_t bits, const uint32_t bit)
44 {
45 return (bits >> bit) & 1ull;
46 }
47
48 // Set the bit field(s) from the most significant bit (msbit) to the
49 // least significant bit (lsbit) of a 32-bit unsigned value to 'val'.
50 static inline void
SetBits32(uint32_t & bits,const uint32_t msbit,const uint32_t lsbit,const uint32_t val)51 SetBits32(uint32_t &bits, const uint32_t msbit, const uint32_t lsbit, const uint32_t val)
52 {
53 assert(msbit < 32 && lsbit < 32 && msbit >= lsbit);
54 uint32_t mask = ((1u << (msbit - lsbit + 1)) - 1);
55 bits &= ~(mask << lsbit);
56 bits |= (val & mask) << lsbit;
57 }
58
59 // Set the 'bit' position of a 32-bit unsigned value to 'val'.
60 static inline void
SetBit32(uint32_t & bits,const uint32_t bit,const uint32_t val)61 SetBit32(uint32_t &bits, const uint32_t bit, const uint32_t val)
62 {
63 SetBits32(bits, bit, bit, val);
64 }
65
66 // Rotate a 32-bit unsigned value right by the specified amount.
67 static inline uint32_t
Rotr32(uint32_t bits,uint32_t amt)68 Rotr32 (uint32_t bits, uint32_t amt)
69 {
70 assert(amt < 32 && "Invalid rotate amount");
71 return (bits >> amt) | (bits << ((32-amt)&31));
72 }
73
74 // Rotate a 32-bit unsigned value left by the specified amount.
75 static inline uint32_t
Rotl32(uint32_t bits,uint32_t amt)76 Rotl32 (uint32_t bits, uint32_t amt)
77 {
78 assert(amt < 32 && "Invalid rotate amount");
79 return (bits << amt) | (bits >> ((32-amt)&31));
80 }
81
82 // Create a mask that starts at bit zero and includes "bit"
83 static inline uint64_t
MaskUpToBit(const uint64_t bit)84 MaskUpToBit (const uint64_t bit)
85 {
86 return (1ull << (bit + 1ull)) - 1ull;
87 }
88
89 // Return an integer result equal to the number of bits of x that are ones.
90 static inline uint32_t
BitCount(uint64_t x)91 BitCount (uint64_t x)
92 {
93 // c accumulates the total bits set in x
94 uint32_t c;
95 for (c = 0; x; ++c)
96 {
97 x &= x - 1; // clear the least significant bit set
98 }
99 return c;
100 }
101
102 static inline bool
BitIsSet(const uint64_t value,const uint64_t bit)103 BitIsSet (const uint64_t value, const uint64_t bit)
104 {
105 return (value & (1ull << bit)) != 0;
106 }
107
108 static inline bool
BitIsClear(const uint64_t value,const uint64_t bit)109 BitIsClear (const uint64_t value, const uint64_t bit)
110 {
111 return (value & (1ull << bit)) == 0;
112 }
113
114 static inline uint64_t
UnsignedBits(const uint64_t value,const uint64_t msbit,const uint64_t lsbit)115 UnsignedBits (const uint64_t value, const uint64_t msbit, const uint64_t lsbit)
116 {
117 uint64_t result = value >> lsbit;
118 result &= MaskUpToBit (msbit - lsbit);
119 return result;
120 }
121
122 static inline int64_t
SignedBits(const uint64_t value,const uint64_t msbit,const uint64_t lsbit)123 SignedBits (const uint64_t value, const uint64_t msbit, const uint64_t lsbit)
124 {
125 uint64_t result = UnsignedBits (value, msbit, lsbit);
126 if (BitIsSet(value, msbit))
127 {
128 // Sign extend
129 result |= ~MaskUpToBit (msbit - lsbit);
130 }
131 return result;
132 }
133
134 } // namespace lldb_private
135
136 #endif // lldb_InstructionUtils_h_
137