//===-- X86Disassembler.h - Disassembler for x86 and x86_64 -----*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // The X86 disassembler is a table-driven disassembler for the 16-, 32-, and // 64-bit X86 instruction sets. The main decode sequence for an assembly // instruction in this disassembler is: // // 1. Read the prefix bytes and determine the attributes of the instruction. // These attributes, recorded in enum attributeBits // (X86DisassemblerDecoderCommon.h), form a bitmask. The table CONTEXTS_SYM // provides a mapping from bitmasks to contexts, which are represented by // enum InstructionContext (ibid.). // // 2. Read the opcode, and determine what kind of opcode it is. The // disassembler distinguishes four kinds of opcodes, which are enumerated in // OpcodeType (X86DisassemblerDecoderCommon.h): one-byte (0xnn), two-byte // (0x0f 0xnn), three-byte-38 (0x0f 0x38 0xnn), or three-byte-3a // (0x0f 0x3a 0xnn). Mandatory prefixes are treated as part of the context. // // 3. Depending on the opcode type, look in one of four ClassDecision structures // (X86DisassemblerDecoderCommon.h). Use the opcode class to determine which // OpcodeDecision (ibid.) to look the opcode in. Look up the opcode, to get // a ModRMDecision (ibid.). // // 4. Some instructions, such as escape opcodes or extended opcodes, or even // instructions that have ModRM*Reg / ModRM*Mem forms in LLVM, need the // ModR/M byte to complete decode. The ModRMDecision's type is an entry from // ModRMDecisionType (X86DisassemblerDecoderCommon.h) that indicates if the // ModR/M byte is required and how to interpret it. // // 5. After resolving the ModRMDecision, the disassembler has a unique ID // of type InstrUID (X86DisassemblerDecoderCommon.h). Looking this ID up in // INSTRUCTIONS_SYM yields the name of the instruction and the encodings and // meanings of its operands. // // 6. For each operand, its encoding is an entry from OperandEncoding // (X86DisassemblerDecoderCommon.h) and its type is an entry from // OperandType (ibid.). The encoding indicates how to read it from the // instruction; the type indicates how to interpret the value once it has // been read. For example, a register operand could be stored in the R/M // field of the ModR/M byte, the REG field of the ModR/M byte, or added to // the main opcode. This is orthogonal from its meaning (an GPR or an XMM // register, for instance). Given this information, the operands can be // extracted and interpreted. // // 7. As the last step, the disassembler translates the instruction information // and operands into a format understandable by the client - in this case, an // MCInst for use by the MC infrastructure. // // The disassembler is broken broadly into two parts: the table emitter that // emits the instruction decode tables discussed above during compilation, and // the disassembler itself. The table emitter is documented in more detail in // utils/TableGen/X86DisassemblerEmitter.h. // // X86Disassembler.h contains the public interface for the disassembler, // adhering to the MCDisassembler interface. // X86Disassembler.cpp contains the code responsible for step 7, and for // invoking the decoder to execute steps 1-6. // X86DisassemblerDecoderCommon.h contains the definitions needed by both the // table emitter and the disassembler. // X86DisassemblerDecoder.h contains the public interface of the decoder, // factored out into C for possible use by other projects. // X86DisassemblerDecoder.c contains the source code of the decoder, which is // responsible for steps 1-6. // //===----------------------------------------------------------------------===// /* Capstone Disassembly Engine */ /* By Nguyen Anh Quynh , 2013-2014 */ #ifndef CS_X86_DISASSEMBLER_H #define CS_X86_DISASSEMBLER_H #if !defined(_MSC_VER) || !defined(_KERNEL_MODE) #include #endif #include "../../include/capstone.h" #include "../../MCInst.h" #include "../../MCRegisterInfo.h" #include "X86DisassemblerDecoderCommon.h" bool X86_getInstruction(csh handle, const uint8_t *code, size_t code_len, MCInst *instr, uint16_t *size, uint64_t address, void *info); void X86_init(MCRegisterInfo *MRI); #endif