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riscv.h
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1/* Common target-dependent functionality for RISC-V
2
3 Copyright (C) 2018-2023 Free Software Foundation, Inc.
4
5 This file is part of GDB.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19
20#ifndef ARCH_RISCV_H
21#define ARCH_RISCV_H
22
23#include "gdbsupport/tdesc.h"
24
25/* The set of RISC-V architectural features that we track that impact how
26 we configure the actual gdbarch instance. We hold one of these in the
27 gdbarch_tdep structure, and use it to distinguish between different
28 RISC-V gdbarch instances.
29
30 The information in here ideally comes from the target description,
31 however, if the target doesn't provide a target description then we will
32 create a default target description by first populating one of these
33 based on what we know about the binary being executed, and using that to
34 drive default target description creation. */
35
37{
38 /* The size of the x-registers in bytes. This is either 4 (RV32), 8
39 (RV64), or 16 (RV128). No other value is valid. Initialise to the
40 invalid 0 value so we can spot if one of these is used
41 uninitialised. */
42 int xlen = 0;
43
44 /* The size of the f-registers in bytes. This is either 4 (RV32), 8
45 (RV64), or 16 (RV128). This can also hold the value 0 to indicate
46 that there are no f-registers. No other value is valid. */
47 int flen = 0;
48
49 /* The size of the v-registers in bytes. The value 0 indicates a target
50 with no vector registers. The minimum value for a standard compliant
51 target should be 16, but GDB doesn't currently mind, and will accept
52 any vector size. */
53 int vlen = 0;
54
55 /* When true this target is RV32E. */
56 bool embedded = false;
57
58 /* Track if the target description has an fcsr, fflags, and frm
59 registers. Some targets provide all these in their target
60 descriptions, while some only offer fcsr, while others don't even
61 offer that register. If a target provides fcsr but not fflags and/or
62 frm, then we can emulate these registers as pseudo registers. */
63 bool has_fcsr_reg = false;
64 bool has_fflags_reg = false;
65 bool has_frm_reg = false;
66
67 /* Equality operator. */
68 bool operator== (const struct riscv_gdbarch_features &rhs) const
69 {
70 return (xlen == rhs.xlen && flen == rhs.flen
71 && embedded == rhs.embedded && vlen == rhs.vlen
73 && has_frm_reg == rhs.has_frm_reg
74 && has_fcsr_reg == rhs.has_fcsr_reg);
75 }
76
77 /* Inequality operator. */
78 bool operator!= (const struct riscv_gdbarch_features &rhs) const
79 {
80 return !((*this) == rhs);
81 }
82
83 /* Used by std::unordered_map to hash feature sets. */
84 std::size_t hash () const noexcept
85 {
86 std::size_t val = ((embedded ? 1 : 0) << 10
87 | (has_fflags_reg ? 1 : 0) << 11
88 | (has_frm_reg ? 1 : 0) << 12
89 | (has_fcsr_reg ? 1 : 0) << 13
90 | (xlen & 0x1f) << 5
91 | (flen & 0x1f) << 0
92 | (vlen & 0xfff) << 14);
93 return val;
94 }
95};
96
97#ifdef GDBSERVER
98
99/* Create and return a target description that is compatible with FEATURES.
100 This is only used directly from the gdbserver where the created target
101 description is modified after it is return. */
102
104 (const struct riscv_gdbarch_features features);
105
106#else
107
108/* Lookup an already existing target description matching FEATURES, or
109 create a new target description if this is the first time we have seen
110 FEATURES. For the same FEATURES the same target_desc is always
111 returned. This is important when trying to lookup gdbarch objects as
112 GDBARCH_LIST_LOOKUP_BY_INFO performs a pointer comparison on target
113 descriptions to find candidate gdbarch objects. */
114
116 (const struct riscv_gdbarch_features features);
117
118#endif /* GDBSERVER */
119
120
121#endif /* ARCH_RISCV_H */
STATIC_IN_GDB target_desc_up riscv_create_target_description(const struct riscv_gdbarch_features features)
Definition: riscv.c:38
const target_desc * riscv_lookup_target_description(const struct riscv_gdbarch_features features)
Definition: riscv.c:117
bool operator==(const struct riscv_gdbarch_features &rhs) const
Definition: riscv.h:68
bool operator!=(const struct riscv_gdbarch_features &rhs) const
Definition: riscv.h:78
std::size_t hash() const noexcept
Definition: riscv.h:84