1 //===- X86DisassemblerShared.h - Emitter shared header ----------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLVM_UTILS_TABLEGEN_X86DISASSEMBLERSHARED_H
10 #define LLVM_UTILS_TABLEGEN_X86DISASSEMBLERSHARED_H
11 
12 #include <cstring>
13 #include <string>
14 
15 #include "llvm/Support/X86DisassemblerDecoderCommon.h"
16 
17 struct InstructionSpecifier {
18   llvm::X86Disassembler::OperandSpecifier
19       operands[llvm::X86Disassembler::X86_MAX_OPERANDS];
20   llvm::X86Disassembler::InstructionContext insnContext;
21   std::string name;
22 
InstructionSpecifierInstructionSpecifier23   InstructionSpecifier() {
24     insnContext = llvm::X86Disassembler::IC;
25     name = "";
26     memset(operands, 0, sizeof(operands));
27   }
28 };
29 
30 /// Specifies whether a ModR/M byte is needed and (if so) which
31 /// instruction each possible value of the ModR/M byte corresponds to. Once
32 /// this information is known, we have narrowed down to a single instruction.
33 struct ModRMDecision {
34   uint8_t modrm_type;
35   llvm::X86Disassembler::InstrUID instructionIDs[256];
36 };
37 
38 /// Specifies which set of ModR/M->instruction tables to look at
39 /// given a particular opcode.
40 struct OpcodeDecision {
41   ModRMDecision modRMDecisions[256];
42 };
43 
44 /// Specifies which opcode->instruction tables to look at given
45 /// a particular context (set of attributes).  Since there are many possible
46 /// contexts, the decoder first uses CONTEXTS_SYM to determine which context
47 /// applies given a specific set of attributes.  Hence there are only IC_max
48 /// entries in this table, rather than 2^(ATTR_max).
49 struct ContextDecision {
50   OpcodeDecision opcodeDecisions[llvm::X86Disassembler::IC_max];
51 
ContextDecisionContextDecision52   ContextDecision() {
53     memset(opcodeDecisions, 0, sizeof(opcodeDecisions));
54   }
55 };
56 
57 #endif
58