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
15namespace 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.
19static inline uint64_t
20Bits64 (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.
28static inline uint32_t
29Bits32 (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.
36static inline uint32_t
37Bit32 (const uint32_t bits, const uint32_t bit)
38{
39    return (bits >> bit) & 1u;
40}
41
42static inline uint64_t
43Bit64 (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'.
50static inline void
51SetBits32(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'.
60static inline void
61SetBit32(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.
67static inline uint32_t
68Rotr32 (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.
75static inline uint32_t
76Rotl32 (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"
83static inline uint64_t
84MaskUpToBit (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.
90static inline uint32_t
91BitCount (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
102static inline bool
103BitIsSet (const uint64_t value, const uint64_t bit)
104{
105    return (value & (1ull << bit)) != 0;
106}
107
108static inline bool
109BitIsClear (const uint64_t value, const uint64_t bit)
110{
111    return (value & (1ull << bit)) == 0;
112}
113
114static inline uint64_t
115UnsignedBits (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
122static inline int64_t
123SignedBits (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