1/*
2 * Copyright (c) 2013-2014 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2012 Google
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Gabe Black
41 */
42
43#ifndef __ARCH_ARM_DECODER_HH__
44#define __ARCH_ARM_DECODER_HH__
45
46#include <cassert>
47
48#include "arch/arm/miscregs.hh"
49#include "arch/arm/types.hh"
50#include "arch/generic/decode_cache.hh"
51#include "base/types.hh"
52#include "cpu/static_inst.hh"
53#include "enums/DecoderFlavour.hh"
54
55namespace ArmISA
56{
57
58class ISA;
59class Decoder
60{
61 protected:
62 //The extended machine instruction being generated
63 ExtMachInst emi;
64 MachInst data;
65 bool bigThumb;
66 bool instDone;
67 bool outOfBytes;
68 int offset;
69 bool foundIt;
70 ITSTATE itBits;
71
72 int fpscrLen;
73 int fpscrStride;
74
| 1/*
2 * Copyright (c) 2013-2014 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2012 Google
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Gabe Black
41 */
42
43#ifndef __ARCH_ARM_DECODER_HH__
44#define __ARCH_ARM_DECODER_HH__
45
46#include <cassert>
47
48#include "arch/arm/miscregs.hh"
49#include "arch/arm/types.hh"
50#include "arch/generic/decode_cache.hh"
51#include "base/types.hh"
52#include "cpu/static_inst.hh"
53#include "enums/DecoderFlavour.hh"
54
55namespace ArmISA
56{
57
58class ISA;
59class Decoder
60{
61 protected:
62 //The extended machine instruction being generated
63 ExtMachInst emi;
64 MachInst data;
65 bool bigThumb;
66 bool instDone;
67 bool outOfBytes;
68 int offset;
69 bool foundIt;
70 ITSTATE itBits;
71
72 int fpscrLen;
73 int fpscrStride;
74
|
75 Enums::DecoderFlavour decoderFlavour;
76
77 /// A cache of decoded instruction objects.
78 static GenericISA::BasicDecodeCache defaultCache;
79
80 /**
81 * Pre-decode an instruction from the current state of the
82 * decoder.
83 */
84 void process();
85
86 /**
87 * Consume bytes by moving the offset into the data word and
88 * sanity check the results.
89 */
90 void consumeBytes(int numBytes);
91
92 public: // Decoder API
93 Decoder(ISA* isa = nullptr);
94
95 /** Reset the decoders internal state. */
96 void reset();
97
98 /**
99 * Can the decoder accept more data?
100 *
101 * A CPU model uses this method to determine if the decoder can
102 * accept more data. Note that an instruction can be ready (see
103 * instReady() even if this method returns true.
104 */
105 bool needMoreBytes() const { return outOfBytes; }
106
107 /**
108 * Is an instruction ready to be decoded?
109 *
110 * CPU models call this method to determine if decode() will
111 * return a new instruction on the next call. It typically only
112 * returns false if the decoder hasn't received enough data to
113 * decode a full instruction.
114 */
115 bool instReady() const { return instDone; }
116
117 /**
118 * Feed data to the decoder.
119 *
120 * A CPU model uses this interface to load instruction data into
121 * the decoder. Once enough data has been loaded (check with
122 * instReady()), a decoded instruction can be retrieved using
123 * decode(ArmISA::PCState).
124 *
125 * This method is intended to support both fixed-length and
126 * variable-length instructions. Instruction data is fetch in
127 * MachInst blocks (which correspond to the size of a typical
128 * insturction). The method might need to be called multiple times
129 * if the instruction spans multiple blocks, in that case
130 * needMoreBytes() will return true and instReady() will return
131 * false.
132 *
133 * The fetchPC parameter is used to indicate where in memory the
134 * instruction was fetched from. This is should be the same
135 * address as the pc. If fetching multiple blocks, it indicates
136 * where subsequent blocks are fetched from (pc + n *
137 * sizeof(MachInst)).
138 *
139 * @param pc Instruction pointer that we are decoding.
140 * @param fetchPC The address this chunk was fetched from.
141 * @param inst Raw instruction data.
142 */
143 void moreBytes(const PCState &pc, Addr fetchPC, MachInst inst);
144
145 /**
146 * Decode an instruction or fetch it from the code cache.
147 *
148 * This method decodes the currently pending pre-decoded
149 * instruction. Data must be fed to the decoder using moreBytes()
150 * until instReady() is true before calling this method.
151 *
152 * @param pc Instruction pointer that we are decoding.
153 * @return A pointer to a static instruction or NULL if the
154 * decoder isn't ready (see instReady()).
155 */
156 StaticInstPtr decode(ArmISA::PCState &pc);
157
158 /**
159 * Decode a pre-decoded machine instruction.
160 *
161 * @warn This method takes a pre-decoded instruction as its
162 * argument. It should typically not be called directly.
163 *
164 * @param mach_inst A pre-decoded instruction
165 * @retval A pointer to the corresponding StaticInst object.
166 */
167 StaticInstPtr decode(ExtMachInst mach_inst, Addr addr)
168 {
169 return defaultCache.decode(this, mach_inst, addr);
170 }
171
172 /**
173 * Decode a machine instruction without calling the cache.
174 *
175 * @note The implementation of this method is generated by the ISA
176 * parser script.
177 *
178 * @warn This method takes a pre-decoded instruction as its
179 * argument. It should typically not be called directly.
180 *
181 * @param mach_inst The binary instruction to decode.
182 * @retval A pointer to the corresponding StaticInst object.
183 */
184 StaticInstPtr decodeInst(ExtMachInst mach_inst);
185
186 /**
187 * Take over the state from an old decoder when switching CPUs.
188 *
189 * @param old Decoder used in old CPU
190 */
191 void takeOverFrom(Decoder *old) {}
192
193
194 public: // ARM-specific decoder state manipulation
195 void setContext(FPSCR fpscr)
196 {
197 fpscrLen = fpscr.len;
198 fpscrStride = fpscr.stride;
199 }
| 81 Enums::DecoderFlavour decoderFlavour;
82
83 /// A cache of decoded instruction objects.
84 static GenericISA::BasicDecodeCache defaultCache;
85
86 /**
87 * Pre-decode an instruction from the current state of the
88 * decoder.
89 */
90 void process();
91
92 /**
93 * Consume bytes by moving the offset into the data word and
94 * sanity check the results.
95 */
96 void consumeBytes(int numBytes);
97
98 public: // Decoder API
99 Decoder(ISA* isa = nullptr);
100
101 /** Reset the decoders internal state. */
102 void reset();
103
104 /**
105 * Can the decoder accept more data?
106 *
107 * A CPU model uses this method to determine if the decoder can
108 * accept more data. Note that an instruction can be ready (see
109 * instReady() even if this method returns true.
110 */
111 bool needMoreBytes() const { return outOfBytes; }
112
113 /**
114 * Is an instruction ready to be decoded?
115 *
116 * CPU models call this method to determine if decode() will
117 * return a new instruction on the next call. It typically only
118 * returns false if the decoder hasn't received enough data to
119 * decode a full instruction.
120 */
121 bool instReady() const { return instDone; }
122
123 /**
124 * Feed data to the decoder.
125 *
126 * A CPU model uses this interface to load instruction data into
127 * the decoder. Once enough data has been loaded (check with
128 * instReady()), a decoded instruction can be retrieved using
129 * decode(ArmISA::PCState).
130 *
131 * This method is intended to support both fixed-length and
132 * variable-length instructions. Instruction data is fetch in
133 * MachInst blocks (which correspond to the size of a typical
134 * insturction). The method might need to be called multiple times
135 * if the instruction spans multiple blocks, in that case
136 * needMoreBytes() will return true and instReady() will return
137 * false.
138 *
139 * The fetchPC parameter is used to indicate where in memory the
140 * instruction was fetched from. This is should be the same
141 * address as the pc. If fetching multiple blocks, it indicates
142 * where subsequent blocks are fetched from (pc + n *
143 * sizeof(MachInst)).
144 *
145 * @param pc Instruction pointer that we are decoding.
146 * @param fetchPC The address this chunk was fetched from.
147 * @param inst Raw instruction data.
148 */
149 void moreBytes(const PCState &pc, Addr fetchPC, MachInst inst);
150
151 /**
152 * Decode an instruction or fetch it from the code cache.
153 *
154 * This method decodes the currently pending pre-decoded
155 * instruction. Data must be fed to the decoder using moreBytes()
156 * until instReady() is true before calling this method.
157 *
158 * @param pc Instruction pointer that we are decoding.
159 * @return A pointer to a static instruction or NULL if the
160 * decoder isn't ready (see instReady()).
161 */
162 StaticInstPtr decode(ArmISA::PCState &pc);
163
164 /**
165 * Decode a pre-decoded machine instruction.
166 *
167 * @warn This method takes a pre-decoded instruction as its
168 * argument. It should typically not be called directly.
169 *
170 * @param mach_inst A pre-decoded instruction
171 * @retval A pointer to the corresponding StaticInst object.
172 */
173 StaticInstPtr decode(ExtMachInst mach_inst, Addr addr)
174 {
175 return defaultCache.decode(this, mach_inst, addr);
176 }
177
178 /**
179 * Decode a machine instruction without calling the cache.
180 *
181 * @note The implementation of this method is generated by the ISA
182 * parser script.
183 *
184 * @warn This method takes a pre-decoded instruction as its
185 * argument. It should typically not be called directly.
186 *
187 * @param mach_inst The binary instruction to decode.
188 * @retval A pointer to the corresponding StaticInst object.
189 */
190 StaticInstPtr decodeInst(ExtMachInst mach_inst);
191
192 /**
193 * Take over the state from an old decoder when switching CPUs.
194 *
195 * @param old Decoder used in old CPU
196 */
197 void takeOverFrom(Decoder *old) {}
198
199
200 public: // ARM-specific decoder state manipulation
201 void setContext(FPSCR fpscr)
202 {
203 fpscrLen = fpscr.len;
204 fpscrStride = fpscr.stride;
205 }
|