/*===-- X86DisassemblerDecoder.c - Disassembler decoder ------------*- C -*-===* * * The LLVM Compiler Infrastructure * * This file is distributed under the University of Illinois Open Source * License. See LICENSE.TXT for details. * *===----------------------------------------------------------------------===* * * This file is part of the X86 Disassembler. * It contains the implementation of the instruction decoder. * Documentation for the disassembler can be found in X86Disassembler.h. * *===----------------------------------------------------------------------===*/ /* Capstone Disassembly Engine */ /* By Nguyen Anh Quynh , 2013-2014 */ #ifdef CAPSTONE_HAS_X86 #include /* for va_*() */ #if defined(CAPSTONE_HAS_OSXKERNEL) #include #else #include /* for exit() */ #endif #include "../../cs_priv.h" #include "../../utils.h" #include "X86DisassemblerDecoder.h" /// Specifies whether a ModR/M byte is needed and (if so) which /// instruction each possible value of the ModR/M byte corresponds to. Once /// this information is known, we have narrowed down to a single instruction. struct ModRMDecision { uint8_t modrm_type; uint16_t instructionIDs; }; /// Specifies which set of ModR/M->instruction tables to look at /// given a particular opcode. struct OpcodeDecision { struct ModRMDecision modRMDecisions[256]; }; /// Specifies which opcode->instruction tables to look at given /// a particular context (set of attributes). Since there are many possible /// contexts, the decoder first uses CONTEXTS_SYM to determine which context /// applies given a specific set of attributes. Hence there are only IC_max /// entries in this table, rather than 2^(ATTR_max). struct ContextDecision { struct OpcodeDecision opcodeDecisions[IC_max]; }; #ifdef CAPSTONE_X86_REDUCE #include "X86GenDisassemblerTables_reduce.inc" #else #include "X86GenDisassemblerTables.inc" #endif //#define GET_INSTRINFO_ENUM #define GET_INSTRINFO_MC_DESC #ifdef CAPSTONE_X86_REDUCE #include "X86GenInstrInfo_reduce.inc" #else #include "X86GenInstrInfo.inc" #endif /* * contextForAttrs - Client for the instruction context table. Takes a set of * attributes and returns the appropriate decode context. * * @param attrMask - Attributes, from the enumeration attributeBits. * @return - The InstructionContext to use when looking up an * an instruction with these attributes. */ static InstructionContext contextForAttrs(uint16_t attrMask) { return CONTEXTS_SYM[attrMask]; } /* * modRMRequired - Reads the appropriate instruction table to determine whether * the ModR/M byte is required to decode a particular instruction. * * @param type - The opcode type (i.e., how many bytes it has). * @param insnContext - The context for the instruction, as returned by * contextForAttrs. * @param opcode - The last byte of the instruction's opcode, not counting * ModR/M extensions and escapes. * @return - true if the ModR/M byte is required, false otherwise. */ static int modRMRequired(OpcodeType type, InstructionContext insnContext, uint16_t opcode) { const struct OpcodeDecision *decision = NULL; const uint8_t *indextable = NULL; uint8_t index; switch (type) { default: case ONEBYTE: decision = ONEBYTE_SYM; indextable = index_x86DisassemblerOneByteOpcodes; break; case TWOBYTE: decision = TWOBYTE_SYM; indextable = index_x86DisassemblerTwoByteOpcodes; break; case THREEBYTE_38: decision = THREEBYTE38_SYM; indextable = index_x86DisassemblerThreeByte38Opcodes; break; case THREEBYTE_3A: decision = THREEBYTE3A_SYM; indextable = index_x86DisassemblerThreeByte3AOpcodes; break; #ifndef CAPSTONE_X86_REDUCE case XOP8_MAP: decision = XOP8_MAP_SYM; indextable = index_x86DisassemblerXOP8Opcodes; break; case XOP9_MAP: decision = XOP9_MAP_SYM; indextable = index_x86DisassemblerXOP9Opcodes; break; case XOPA_MAP: decision = XOPA_MAP_SYM; indextable = index_x86DisassemblerXOPAOpcodes; break; case T3DNOW_MAP: // 3DNow instructions always have ModRM byte return true; #endif } index = indextable[insnContext]; if (index) return decision[index - 1].modRMDecisions[opcode].modrm_type != MODRM_ONEENTRY; else return false; } /* * decode - Reads the appropriate instruction table to obtain the unique ID of * an instruction. * * @param type - See modRMRequired(). * @param insnContext - See modRMRequired(). * @param opcode - See modRMRequired(). * @param modRM - The ModR/M byte if required, or any value if not. * @return - The UID of the instruction, or 0 on failure. */ static InstrUID decode(OpcodeType type, InstructionContext insnContext, uint8_t opcode, uint8_t modRM) { const struct ModRMDecision *dec = NULL; const uint8_t *indextable = NULL; uint8_t index; switch (type) { default: case ONEBYTE: indextable = index_x86DisassemblerOneByteOpcodes; index = indextable[insnContext]; if (index) dec = &ONEBYTE_SYM[index - 1].modRMDecisions[opcode]; else dec = &emptyTable.modRMDecisions[opcode]; break; case TWOBYTE: indextable = index_x86DisassemblerTwoByteOpcodes; index = indextable[insnContext]; if (index) dec = &TWOBYTE_SYM[index - 1].modRMDecisions[opcode]; else dec = &emptyTable.modRMDecisions[opcode]; break; case THREEBYTE_38: indextable = index_x86DisassemblerThreeByte38Opcodes; index = indextable[insnContext]; if (index) dec = &THREEBYTE38_SYM[index - 1].modRMDecisions[opcode]; else dec = &emptyTable.modRMDecisions[opcode]; break; case THREEBYTE_3A: indextable = index_x86DisassemblerThreeByte3AOpcodes; index = indextable[insnContext]; if (index) dec = &THREEBYTE3A_SYM[index - 1].modRMDecisions[opcode]; else dec = &emptyTable.modRMDecisions[opcode]; break; #ifndef CAPSTONE_X86_REDUCE case XOP8_MAP: indextable = index_x86DisassemblerXOP8Opcodes; index = indextable[insnContext]; if (index) dec = &XOP8_MAP_SYM[index - 1].modRMDecisions[opcode]; else dec = &emptyTable.modRMDecisions[opcode]; break; case XOP9_MAP: indextable = index_x86DisassemblerXOP9Opcodes; index = indextable[insnContext]; if (index) dec = &XOP9_MAP_SYM[index - 1].modRMDecisions[opcode]; else dec = &emptyTable.modRMDecisions[opcode]; break; case XOPA_MAP: indextable = index_x86DisassemblerXOPAOpcodes; index = indextable[insnContext]; if (index) dec = &XOPA_MAP_SYM[index - 1].modRMDecisions[opcode]; else dec = &emptyTable.modRMDecisions[opcode]; break; case T3DNOW_MAP: indextable = index_x86DisassemblerT3DNOWOpcodes; index = indextable[insnContext]; if (index) dec = &T3DNOW_MAP_SYM[index - 1].modRMDecisions[opcode]; else dec = &emptyTable.modRMDecisions[opcode]; break; #endif } switch (dec->modrm_type) { default: //debug("Corrupt table! Unknown modrm_type"); return 0; case MODRM_ONEENTRY: return modRMTable[dec->instructionIDs]; case MODRM_SPLITRM: if (modFromModRM(modRM) == 0x3) return modRMTable[dec->instructionIDs+1]; return modRMTable[dec->instructionIDs]; case MODRM_SPLITREG: if (modFromModRM(modRM) == 0x3) return modRMTable[dec->instructionIDs+((modRM & 0x38) >> 3)+8]; return modRMTable[dec->instructionIDs+((modRM & 0x38) >> 3)]; case MODRM_SPLITMISC: if (modFromModRM(modRM) == 0x3) return modRMTable[dec->instructionIDs+(modRM & 0x3f)+8]; return modRMTable[dec->instructionIDs+((modRM & 0x38) >> 3)]; case MODRM_FULL: return modRMTable[dec->instructionIDs+modRM]; } } /* * specifierForUID - Given a UID, returns the name and operand specification for * that instruction. * * @param uid - The unique ID for the instruction. This should be returned by * decode(); specifierForUID will not check bounds. * @return - A pointer to the specification for that instruction. */ static const struct InstructionSpecifier *specifierForUID(InstrUID uid) { return &INSTRUCTIONS_SYM[uid]; } /* * consumeByte - Uses the reader function provided by the user to consume one * byte from the instruction's memory and advance the cursor. * * @param insn - The instruction with the reader function to use. The cursor * for this instruction is advanced. * @param byte - A pointer to a pre-allocated memory buffer to be populated * with the data read. * @return - 0 if the read was successful; nonzero otherwise. */ static int consumeByte(struct InternalInstruction *insn, uint8_t *byte) { int ret = insn->reader(insn->readerArg, byte, insn->readerCursor); if (!ret) ++(insn->readerCursor); return ret; } /* * lookAtByte - Like consumeByte, but does not advance the cursor. * * @param insn - See consumeByte(). * @param byte - See consumeByte(). * @return - See consumeByte(). */ static int lookAtByte(struct InternalInstruction *insn, uint8_t *byte) { return insn->reader(insn->readerArg, byte, insn->readerCursor); } static void unconsumeByte(struct InternalInstruction *insn) { insn->readerCursor--; } #define CONSUME_FUNC(name, type) \ static int name(struct InternalInstruction *insn, type *ptr) { \ type combined = 0; \ unsigned offset; \ for (offset = 0; offset < sizeof(type); ++offset) { \ uint8_t byte; \ int ret = insn->reader(insn->readerArg, \ &byte, \ insn->readerCursor + offset); \ if (ret) \ return ret; \ combined = combined | (type)((uint64_t)byte << (offset * 8)); \ } \ *ptr = combined; \ insn->readerCursor += sizeof(type); \ return 0; \ } /* * consume* - Use the reader function provided by the user to consume data * values of various sizes from the instruction's memory and advance the * cursor appropriately. These readers perform endian conversion. * * @param insn - See consumeByte(). * @param ptr - A pointer to a pre-allocated memory of appropriate size to * be populated with the data read. * @return - See consumeByte(). */ CONSUME_FUNC(consumeInt8, int8_t) CONSUME_FUNC(consumeInt16, int16_t) CONSUME_FUNC(consumeInt32, int32_t) CONSUME_FUNC(consumeUInt16, uint16_t) CONSUME_FUNC(consumeUInt32, uint32_t) CONSUME_FUNC(consumeUInt64, uint64_t) /* * setPrefixPresent - Marks that a particular prefix is present at a particular * location. * * @param insn - The instruction to be marked as having the prefix. * @param prefix - The prefix that is present. * @param location - The location where the prefix is located (in the address * space of the instruction's reader). */ static void setPrefixPresent(struct InternalInstruction *insn, uint8_t prefix, uint64_t location) { switch (prefix) { case 0x26: insn->isPrefix26 = true; insn->prefix26 = location; break; case 0x2e: insn->isPrefix2e = true; insn->prefix2e = location; break; case 0x36: insn->isPrefix36 = true; insn->prefix36 = location; break; case 0x3e: insn->isPrefix3e = true; insn->prefix3e = location; break; case 0x64: insn->isPrefix64 = true; insn->prefix64 = location; break; case 0x65: insn->isPrefix65 = true; insn->prefix65 = location; break; case 0x66: insn->isPrefix66 = true; insn->prefix66 = location; break; case 0x67: insn->isPrefix67 = true; insn->prefix67 = location; break; case 0xf0: insn->isPrefixf0 = true; insn->prefixf0 = location; break; case 0xf2: insn->isPrefixf2 = true; insn->prefixf2 = location; break; case 0xf3: insn->isPrefixf3 = true; insn->prefixf3 = location; break; default: break; } } /* * isPrefixAtLocation - Queries an instruction to determine whether a prefix is * present at a given location. * * @param insn - The instruction to be queried. * @param prefix - The prefix. * @param location - The location to query. * @return - Whether the prefix is at that location. */ static bool isPrefixAtLocation(struct InternalInstruction *insn, uint8_t prefix, uint64_t location) { switch (prefix) { case 0x26: if (insn->isPrefix26 && insn->prefix26 == location) return true; break; case 0x2e: if (insn->isPrefix2e && insn->prefix2e == location) return true; break; case 0x36: if (insn->isPrefix36 && insn->prefix36 == location) return true; break; case 0x3e: if (insn->isPrefix3e && insn->prefix3e == location) return true; break; case 0x64: if (insn->isPrefix64 && insn->prefix64 == location) return true; break; case 0x65: if (insn->isPrefix65 && insn->prefix65 == location) return true; break; case 0x66: if (insn->isPrefix66 && insn->prefix66 == location) return true; break; case 0x67: if (insn->isPrefix67 && insn->prefix67 == location) return true; break; case 0xf0: if (insn->isPrefixf0 && insn->prefixf0 == location) return true; break; case 0xf2: if (insn->isPrefixf2 && insn->prefixf2 == location) return true; break; case 0xf3: if (insn->isPrefixf3 && insn->prefixf3 == location) return true; break; default: break; } return false; } /* * readPrefixes - Consumes all of an instruction's prefix bytes, and marks the * instruction as having them. Also sets the instruction's default operand, * address, and other relevant data sizes to report operands correctly. * * @param insn - The instruction whose prefixes are to be read. * @return - 0 if the instruction could be read until the end of the prefix * bytes, and no prefixes conflicted; nonzero otherwise. */ static int readPrefixes(struct InternalInstruction *insn) { bool isPrefix = true; uint64_t prefixLocation; uint8_t byte = 0, nextByte; bool hasAdSize = false; bool hasOpSize = false; while (isPrefix) { if (insn->mode == MODE_64BIT) { // eliminate consecutive redundant REX bytes in front if (consumeByte(insn, &byte)) return -1; if ((byte & 0xf0) == 0x40) { while(true) { if (lookAtByte(insn, &byte)) // out of input code return -1; if ((byte & 0xf0) == 0x40) { // another REX prefix, but we only remember the last one if (consumeByte(insn, &byte)) return -1; } else break; } // recover the last REX byte if next byte is not a legacy prefix switch (byte) { case 0xf2: /* REPNE/REPNZ */ case 0xf3: /* REP or REPE/REPZ */ case 0xf0: /* LOCK */ case 0x2e: /* CS segment override -OR- Branch not taken */ case 0x36: /* SS segment override -OR- Branch taken */ case 0x3e: /* DS segment override */ case 0x26: /* ES segment override */ case 0x64: /* FS segment override */ case 0x65: /* GS segment override */ case 0x66: /* Operand-size override */ case 0x67: /* Address-size override */ break; default: /* Not a prefix byte */ unconsumeByte(insn); break; } } else { unconsumeByte(insn); } } prefixLocation = insn->readerCursor; /* If we fail reading prefixes, just stop here and let the opcode reader deal with it */ if (consumeByte(insn, &byte)) return -1; if (insn->readerCursor - 1 == insn->startLocation && (byte == 0xf2 || byte == 0xf3)) { if (lookAtByte(insn, &nextByte)) return -1; /* * If the byte is 0xf2 or 0xf3, and any of the following conditions are * met: * - it is followed by a LOCK (0xf0) prefix * - it is followed by an xchg instruction * then it should be disassembled as a xacquire/xrelease not repne/rep. */ if ((byte == 0xf2 || byte == 0xf3) && ((nextByte == 0xf0) | ((nextByte & 0xfe) == 0x86 || (nextByte & 0xf8) == 0x90))) insn->xAcquireRelease = true; /* * Also if the byte is 0xf3, and the following condition is met: * - it is followed by a "mov mem, reg" (opcode 0x88/0x89) or * "mov mem, imm" (opcode 0xc6/0xc7) instructions. * then it should be disassembled as an xrelease not rep. */ if (byte == 0xf3 && (nextByte == 0x88 || nextByte == 0x89 || nextByte == 0xc6 || nextByte == 0xc7)) insn->xAcquireRelease = true; if (insn->mode == MODE_64BIT && (nextByte & 0xf0) == 0x40) { if (consumeByte(insn, &nextByte)) return -1; if (lookAtByte(insn, &nextByte)) return -1; unconsumeByte(insn); } } switch (byte) { case 0xf2: /* REPNE/REPNZ */ case 0xf3: /* REP or REPE/REPZ */ case 0xf0: /* LOCK */ // only accept the last prefix insn->isPrefixf2 = false; insn->isPrefixf3 = false; insn->isPrefixf0 = false; setPrefixPresent(insn, byte, prefixLocation); insn->prefix0 = byte; break; case 0x2e: /* CS segment override -OR- Branch not taken */ insn->segmentOverride = SEG_OVERRIDE_CS; // only accept the last prefix insn->isPrefix2e = false; insn->isPrefix36 = false; insn->isPrefix3e = false; insn->isPrefix26 = false; insn->isPrefix64 = false; insn->isPrefix65 = false; setPrefixPresent(insn, byte, prefixLocation); insn->prefix1 = byte; break; case 0x36: /* SS segment override -OR- Branch taken */ insn->segmentOverride = SEG_OVERRIDE_SS; // only accept the last prefix insn->isPrefix2e = false; insn->isPrefix36 = false; insn->isPrefix3e = false; insn->isPrefix26 = false; insn->isPrefix64 = false; insn->isPrefix65 = false; setPrefixPresent(insn, byte, prefixLocation); insn->prefix1 = byte; break; case 0x3e: /* DS segment override */ insn->segmentOverride = SEG_OVERRIDE_DS; // only accept the last prefix insn->isPrefix2e = false; insn->isPrefix36 = false; insn->isPrefix3e = false; insn->isPrefix26 = false; insn->isPrefix64 = false; insn->isPrefix65 = false; setPrefixPresent(insn, byte, prefixLocation); insn->prefix1 = byte; break; case 0x26: /* ES segment override */ insn->segmentOverride = SEG_OVERRIDE_ES; // only accept the last prefix insn->isPrefix2e = false; insn->isPrefix36 = false; insn->isPrefix3e = false; insn->isPrefix26 = false; insn->isPrefix64 = false; insn->isPrefix65 = false; setPrefixPresent(insn, byte, prefixLocation); insn->prefix1 = byte; break; case 0x64: /* FS segment override */ insn->segmentOverride = SEG_OVERRIDE_FS; // only accept the last prefix insn->isPrefix2e = false; insn->isPrefix36 = false; insn->isPrefix3e = false; insn->isPrefix26 = false; insn->isPrefix64 = false; insn->isPrefix65 = false; setPrefixPresent(insn, byte, prefixLocation); insn->prefix1 = byte; break; case 0x65: /* GS segment override */ insn->segmentOverride = SEG_OVERRIDE_GS; // only accept the last prefix insn->isPrefix2e = false; insn->isPrefix36 = false; insn->isPrefix3e = false; insn->isPrefix26 = false; insn->isPrefix64 = false; insn->isPrefix65 = false; setPrefixPresent(insn, byte, prefixLocation); insn->prefix1 = byte; break; case 0x66: /* Operand-size override */ hasOpSize = true; setPrefixPresent(insn, byte, prefixLocation); insn->prefix2 = byte; break; case 0x67: /* Address-size override */ hasAdSize = true; setPrefixPresent(insn, byte, prefixLocation); insn->prefix3 = byte; break; default: /* Not a prefix byte */ isPrefix = false; break; } //if (isPrefix) // dbgprintf(insn, "Found prefix 0x%hhx", byte); } insn->vectorExtensionType = TYPE_NO_VEX_XOP; if (byte == 0x62) { uint8_t byte1, byte2; if (consumeByte(insn, &byte1)) { //dbgprintf(insn, "Couldn't read second byte of EVEX prefix"); return -1; } if ((insn->mode == MODE_64BIT || (byte1 & 0xc0) == 0xc0) && ((~byte1 & 0xc) == 0xc)) { if (lookAtByte(insn, &byte2)) { //dbgprintf(insn, "Couldn't read third byte of EVEX prefix"); return -1; } if ((byte2 & 0x4) == 0x4) { insn->vectorExtensionType = TYPE_EVEX; } else { unconsumeByte(insn); /* unconsume byte1 */ unconsumeByte(insn); /* unconsume byte */ insn->necessaryPrefixLocation = insn->readerCursor - 2; } if (insn->vectorExtensionType == TYPE_EVEX) { insn->vectorExtensionPrefix[0] = byte; insn->vectorExtensionPrefix[1] = byte1; if (consumeByte(insn, &insn->vectorExtensionPrefix[2])) { //dbgprintf(insn, "Couldn't read third byte of EVEX prefix"); return -1; } if (consumeByte(insn, &insn->vectorExtensionPrefix[3])) { //dbgprintf(insn, "Couldn't read fourth byte of EVEX prefix"); return -1; } /* We simulate the REX prefix for simplicity's sake */ if (insn->mode == MODE_64BIT) { insn->rexPrefix = 0x40 | (wFromEVEX3of4(insn->vectorExtensionPrefix[2]) << 3) | (rFromEVEX2of4(insn->vectorExtensionPrefix[1]) << 2) | (xFromEVEX2of4(insn->vectorExtensionPrefix[1]) << 1) | (bFromEVEX2of4(insn->vectorExtensionPrefix[1]) << 0); } switch (ppFromEVEX3of4(insn->vectorExtensionPrefix[2])) { default: break; case VEX_PREFIX_66: hasOpSize = true; break; } //dbgprintf(insn, "Found EVEX prefix 0x%hhx 0x%hhx 0x%hhx 0x%hhx", // insn->vectorExtensionPrefix[0], insn->vectorExtensionPrefix[1], // insn->vectorExtensionPrefix[2], insn->vectorExtensionPrefix[3]); } } else { // BOUND instruction unconsumeByte(insn); /* unconsume byte1 */ unconsumeByte(insn); /* unconsume byte */ } } else if (byte == 0xc4) { uint8_t byte1; if (lookAtByte(insn, &byte1)) { //dbgprintf(insn, "Couldn't read second byte of VEX"); return -1; } if (insn->mode == MODE_64BIT || (byte1 & 0xc0) == 0xc0) { insn->vectorExtensionType = TYPE_VEX_3B; insn->necessaryPrefixLocation = insn->readerCursor - 1; } else { unconsumeByte(insn); insn->necessaryPrefixLocation = insn->readerCursor - 1; } if (insn->vectorExtensionType == TYPE_VEX_3B) { insn->vectorExtensionPrefix[0] = byte; if (consumeByte(insn, &insn->vectorExtensionPrefix[1])) return -1; if (consumeByte(insn, &insn->vectorExtensionPrefix[2])) return -1; /* We simulate the REX prefix for simplicity's sake */ if (insn->mode == MODE_64BIT) { insn->rexPrefix = 0x40 | (wFromVEX3of3(insn->vectorExtensionPrefix[2]) << 3) | (rFromVEX2of3(insn->vectorExtensionPrefix[1]) << 2) | (xFromVEX2of3(insn->vectorExtensionPrefix[1]) << 1) | (bFromVEX2of3(insn->vectorExtensionPrefix[1]) << 0); } switch (ppFromVEX3of3(insn->vectorExtensionPrefix[2])) { default: break; case VEX_PREFIX_66: hasOpSize = true; break; } } } else if (byte == 0xc5) { uint8_t byte1; if (lookAtByte(insn, &byte1)) { //dbgprintf(insn, "Couldn't read second byte of VEX"); return -1; } if (insn->mode == MODE_64BIT || (byte1 & 0xc0) == 0xc0) { insn->vectorExtensionType = TYPE_VEX_2B; } else { unconsumeByte(insn); } if (insn->vectorExtensionType == TYPE_VEX_2B) { insn->vectorExtensionPrefix[0] = byte; if (consumeByte(insn, &insn->vectorExtensionPrefix[1])) return -1; if (insn->mode == MODE_64BIT) { insn->rexPrefix = 0x40 | (rFromVEX2of2(insn->vectorExtensionPrefix[1]) << 2); } switch (ppFromVEX2of2(insn->vectorExtensionPrefix[1])) { default: break; case VEX_PREFIX_66: hasOpSize = true; break; } } } else if (byte == 0x8f) { uint8_t byte1; if (lookAtByte(insn, &byte1)) { // dbgprintf(insn, "Couldn't read second byte of XOP"); return -1; } if ((byte1 & 0x38) != 0x0) { /* 0 in these 3 bits is a POP instruction. */ insn->vectorExtensionType = TYPE_XOP; insn->necessaryPrefixLocation = insn->readerCursor - 1; } else { unconsumeByte(insn); insn->necessaryPrefixLocation = insn->readerCursor - 1; } if (insn->vectorExtensionType == TYPE_XOP) { insn->vectorExtensionPrefix[0] = byte; if (consumeByte(insn, &insn->vectorExtensionPrefix[1])) return -1; if (consumeByte(insn, &insn->vectorExtensionPrefix[2])) return -1; /* We simulate the REX prefix for simplicity's sake */ if (insn->mode == MODE_64BIT) { insn->rexPrefix = 0x40 | (wFromXOP3of3(insn->vectorExtensionPrefix[2]) << 3) | (rFromXOP2of3(insn->vectorExtensionPrefix[1]) << 2) | (xFromXOP2of3(insn->vectorExtensionPrefix[1]) << 1) | (bFromXOP2of3(insn->vectorExtensionPrefix[1]) << 0); } switch (ppFromXOP3of3(insn->vectorExtensionPrefix[2])) { default: break; case VEX_PREFIX_66: hasOpSize = true; break; } } } else { if (insn->mode == MODE_64BIT) { if ((byte & 0xf0) == 0x40) { uint8_t opcodeByte; while(true) { if (lookAtByte(insn, &opcodeByte)) // out of input code return -1; if ((opcodeByte & 0xf0) == 0x40) { // another REX prefix, but we only remember the last one if (consumeByte(insn, &byte)) return -1; } else break; } insn->rexPrefix = byte; insn->necessaryPrefixLocation = insn->readerCursor - 2; // dbgprintf(insn, "Found REX prefix 0x%hhx", byte); } else { unconsumeByte(insn); insn->necessaryPrefixLocation = insn->readerCursor - 1; } } else { unconsumeByte(insn); insn->necessaryPrefixLocation = insn->readerCursor - 1; } } if (insn->mode == MODE_16BIT) { insn->registerSize = (hasOpSize ? 4 : 2); insn->addressSize = (hasAdSize ? 4 : 2); insn->displacementSize = (hasAdSize ? 4 : 2); insn->immediateSize = (hasOpSize ? 4 : 2); insn->immSize = (hasOpSize ? 4 : 2); } else if (insn->mode == MODE_32BIT) { insn->registerSize = (hasOpSize ? 2 : 4); insn->addressSize = (hasAdSize ? 2 : 4); insn->displacementSize = (hasAdSize ? 2 : 4); insn->immediateSize = (hasOpSize ? 2 : 4); insn->immSize = (hasOpSize ? 2 : 4); } else if (insn->mode == MODE_64BIT) { if (insn->rexPrefix && wFromREX(insn->rexPrefix)) { insn->registerSize = 8; insn->addressSize = (hasAdSize ? 4 : 8); insn->displacementSize = 4; insn->immediateSize = 4; insn->immSize = 4; } else if (insn->rexPrefix) { insn->registerSize = (hasOpSize ? 2 : 4); insn->addressSize = (hasAdSize ? 4 : 8); insn->displacementSize = (hasOpSize ? 2 : 4); insn->immediateSize = (hasOpSize ? 2 : 4); insn->immSize = (hasOpSize ? 2 : 4); } else { insn->registerSize = (hasOpSize ? 2 : 4); insn->addressSize = (hasAdSize ? 4 : 8); insn->displacementSize = (hasOpSize ? 2 : 4); insn->immediateSize = (hasOpSize ? 2 : 4); insn->immSize = (hasOpSize ? 4 : 8); } } return 0; } static int readModRM(struct InternalInstruction *insn); /* * readOpcode - Reads the opcode (excepting the ModR/M byte in the case of * extended or escape opcodes). * * @param insn - The instruction whose opcode is to be read. * @return - 0 if the opcode could be read successfully; nonzero otherwise. */ static int readOpcode(struct InternalInstruction *insn) { /* Determine the length of the primary opcode */ uint8_t current; // printf(">>> readOpcode() = %x\n", insn->readerCursor); insn->opcodeType = ONEBYTE; insn->firstByte = 0x00; if (insn->vectorExtensionType == TYPE_EVEX) { switch (mmFromEVEX2of4(insn->vectorExtensionPrefix[1])) { default: // dbgprintf(insn, "Unhandled mm field for instruction (0x%hhx)", // mmFromEVEX2of4(insn->vectorExtensionPrefix[1])); return -1; case VEX_LOB_0F: insn->opcodeType = TWOBYTE; return consumeByte(insn, &insn->opcode); case VEX_LOB_0F38: insn->opcodeType = THREEBYTE_38; return consumeByte(insn, &insn->opcode); case VEX_LOB_0F3A: insn->opcodeType = THREEBYTE_3A; return consumeByte(insn, &insn->opcode); } } else if (insn->vectorExtensionType == TYPE_VEX_3B) { switch (mmmmmFromVEX2of3(insn->vectorExtensionPrefix[1])) { default: // dbgprintf(insn, "Unhandled m-mmmm field for instruction (0x%hhx)", // mmmmmFromVEX2of3(insn->vectorExtensionPrefix[1])); return -1; case VEX_LOB_0F: insn->twoByteEscape = 0x0f; insn->opcodeType = TWOBYTE; return consumeByte(insn, &insn->opcode); case VEX_LOB_0F38: insn->twoByteEscape = 0x0f; insn->threeByteEscape = 0x38; insn->opcodeType = THREEBYTE_38; return consumeByte(insn, &insn->opcode); case VEX_LOB_0F3A: insn->twoByteEscape = 0x0f; insn->threeByteEscape = 0x3a; insn->opcodeType = THREEBYTE_3A; return consumeByte(insn, &insn->opcode); } } else if (insn->vectorExtensionType == TYPE_VEX_2B) { insn->twoByteEscape = 0x0f; insn->opcodeType = TWOBYTE; return consumeByte(insn, &insn->opcode); } else if (insn->vectorExtensionType == TYPE_XOP) { switch (mmmmmFromXOP2of3(insn->vectorExtensionPrefix[1])) { default: // dbgprintf(insn, "Unhandled m-mmmm field for instruction (0x%hhx)", // mmmmmFromVEX2of3(insn->vectorExtensionPrefix[1])); return -1; case XOP_MAP_SELECT_8: // FIXME: twoByteEscape? insn->opcodeType = XOP8_MAP; return consumeByte(insn, &insn->opcode); case XOP_MAP_SELECT_9: // FIXME: twoByteEscape? insn->opcodeType = XOP9_MAP; return consumeByte(insn, &insn->opcode); case XOP_MAP_SELECT_A: // FIXME: twoByteEscape? insn->opcodeType = XOPA_MAP; return consumeByte(insn, &insn->opcode); } } if (consumeByte(insn, ¤t)) return -1; // save this first byte for MOVcr, MOVdr, MOVrc, MOVrd insn->firstByte = current; if (current == 0x0f) { // dbgprintf(insn, "Found a two-byte escape prefix (0x%hhx)", current); insn->twoByteEscape = current; if (consumeByte(insn, ¤t)) return -1; if (current == 0x38) { // dbgprintf(insn, "Found a three-byte escape prefix (0x%hhx)", current); insn->threeByteEscape = current; if (consumeByte(insn, ¤t)) return -1; insn->opcodeType = THREEBYTE_38; } else if (current == 0x3a) { // dbgprintf(insn, "Found a three-byte escape prefix (0x%hhx)", current); insn->threeByteEscape = current; if (consumeByte(insn, ¤t)) return -1; insn->opcodeType = THREEBYTE_3A; } else { #ifndef CAPSTONE_X86_REDUCE switch(current) { default: // dbgprintf(insn, "Didn't find a three-byte escape prefix"); insn->opcodeType = TWOBYTE; break; case 0x0e: // HACK for femms. to be handled properly in next version 3.x insn->opcodeType = T3DNOW_MAP; // this encode does not have ModRM insn->consumedModRM = true; break; case 0x0f: // 3DNow instruction has weird format: ModRM/SIB/displacement + opcode if (readModRM(insn)) return -1; // next is 3DNow opcode if (consumeByte(insn, ¤t)) return -1; insn->opcodeType = T3DNOW_MAP; break; } #endif } } /* * At this point we have consumed the full opcode. * Anything we consume from here on must be unconsumed. */ insn->opcode = current; return 0; } // Hacky for FEMMS #define GET_INSTRINFO_ENUM #ifndef CAPSTONE_X86_REDUCE #include "X86GenInstrInfo.inc" #else #include "X86GenInstrInfo_reduce.inc" #endif /* * getIDWithAttrMask - Determines the ID of an instruction, consuming * the ModR/M byte as appropriate for extended and escape opcodes, * and using a supplied attribute mask. * * @param instructionID - A pointer whose target is filled in with the ID of the * instruction. * @param insn - The instruction whose ID is to be determined. * @param attrMask - The attribute mask to search. * @return - 0 if the ModR/M could be read when needed or was not * needed; nonzero otherwise. */ static int getIDWithAttrMask(uint16_t *instructionID, struct InternalInstruction *insn, uint16_t attrMask) { bool hasModRMExtension; InstructionContext instructionClass; #ifndef CAPSTONE_X86_REDUCE // HACK for femms. to be handled properly in next version 3.x if (insn->opcode == 0x0e && insn->opcodeType == T3DNOW_MAP) { *instructionID = X86_FEMMS; return 0; } #endif if (insn->opcodeType == T3DNOW_MAP) instructionClass = IC_OF; else instructionClass = contextForAttrs(attrMask); hasModRMExtension = modRMRequired(insn->opcodeType, instructionClass, insn->opcode) != 0; if (hasModRMExtension) { if (readModRM(insn)) return -1; *instructionID = decode(insn->opcodeType, instructionClass, insn->opcode, insn->modRM); } else { *instructionID = decode(insn->opcodeType, instructionClass, insn->opcode, 0); } return 0; } /* * is16BitEquivalent - Determines whether two instruction names refer to * equivalent instructions but one is 16-bit whereas the other is not. * * @param orig - The instruction ID that is not 16-bit * @param equiv - The instruction ID that is 16-bit */ static bool is16BitEquivalent(unsigned orig, unsigned equiv) { size_t i; uint16_t idx; if ((idx = x86_16_bit_eq_lookup[orig]) != 0) { for (i = idx - 1; i < ARR_SIZE(x86_16_bit_eq_tbl) && x86_16_bit_eq_tbl[i].first == orig; i++) { if (x86_16_bit_eq_tbl[i].second == equiv) return true; } } return false; } /* * getID - Determines the ID of an instruction, consuming the ModR/M byte as * appropriate for extended and escape opcodes. Determines the attributes and * context for the instruction before doing so. * * @param insn - The instruction whose ID is to be determined. * @return - 0 if the ModR/M could be read when needed or was not needed; * nonzero otherwise. */ static int getID(struct InternalInstruction *insn) { uint16_t attrMask; uint16_t instructionID; const struct InstructionSpecifier *spec; // printf(">>> getID()\n"); attrMask = ATTR_NONE; if (insn->mode == MODE_64BIT) attrMask |= ATTR_64BIT; if (insn->vectorExtensionType != TYPE_NO_VEX_XOP) { attrMask |= (insn->vectorExtensionType == TYPE_EVEX) ? ATTR_EVEX : ATTR_VEX; if (insn->vectorExtensionType == TYPE_EVEX) { switch (ppFromEVEX3of4(insn->vectorExtensionPrefix[2])) { case VEX_PREFIX_66: attrMask |= ATTR_OPSIZE; break; case VEX_PREFIX_F3: attrMask |= ATTR_XS; break; case VEX_PREFIX_F2: attrMask |= ATTR_XD; break; } if (zFromEVEX4of4(insn->vectorExtensionPrefix[3])) attrMask |= ATTR_EVEXKZ; if (bFromEVEX4of4(insn->vectorExtensionPrefix[3])) attrMask |= ATTR_EVEXB; if (aaaFromEVEX4of4(insn->vectorExtensionPrefix[3])) attrMask |= ATTR_EVEXK; if (lFromEVEX4of4(insn->vectorExtensionPrefix[3])) attrMask |= ATTR_EVEXL; if (l2FromEVEX4of4(insn->vectorExtensionPrefix[3])) attrMask |= ATTR_EVEXL2; } else if (insn->vectorExtensionType == TYPE_VEX_3B) { switch (ppFromVEX3of3(insn->vectorExtensionPrefix[2])) { case VEX_PREFIX_66: attrMask |= ATTR_OPSIZE; break; case VEX_PREFIX_F3: attrMask |= ATTR_XS; break; case VEX_PREFIX_F2: attrMask |= ATTR_XD; break; } if (lFromVEX3of3(insn->vectorExtensionPrefix[2])) attrMask |= ATTR_VEXL; } else if (insn->vectorExtensionType == TYPE_VEX_2B) { switch (ppFromVEX2of2(insn->vectorExtensionPrefix[1])) { case VEX_PREFIX_66: attrMask |= ATTR_OPSIZE; break; case VEX_PREFIX_F3: attrMask |= ATTR_XS; break; case VEX_PREFIX_F2: attrMask |= ATTR_XD; break; } if (lFromVEX2of2(insn->vectorExtensionPrefix[1])) attrMask |= ATTR_VEXL; } else if (insn->vectorExtensionType == TYPE_XOP) { switch (ppFromXOP3of3(insn->vectorExtensionPrefix[2])) { case VEX_PREFIX_66: attrMask |= ATTR_OPSIZE; break; case VEX_PREFIX_F3: attrMask |= ATTR_XS; break; case VEX_PREFIX_F2: attrMask |= ATTR_XD; break; } if (lFromXOP3of3(insn->vectorExtensionPrefix[2])) attrMask |= ATTR_VEXL; } else { return -1; } } else { if (insn->mode != MODE_16BIT && isPrefixAtLocation(insn, 0x66, insn->necessaryPrefixLocation)) { attrMask |= ATTR_OPSIZE; } else if (isPrefixAtLocation(insn, 0x67, insn->necessaryPrefixLocation)) { attrMask |= ATTR_ADSIZE; } else if (insn->mode != MODE_16BIT && isPrefixAtLocation(insn, 0xf3, insn->necessaryPrefixLocation)) { attrMask |= ATTR_XS; } else if (insn->mode != MODE_16BIT && isPrefixAtLocation(insn, 0xf2, insn->necessaryPrefixLocation)) { attrMask |= ATTR_XD; } } if (insn->rexPrefix & 0x08) attrMask |= ATTR_REXW; if (getIDWithAttrMask(&instructionID, insn, attrMask)) return -1; /* Fixing CALL and JMP instruction when in 64bit mode and x66 prefix is used */ if (insn->mode == MODE_64BIT && insn->isPrefix66 && (insn->opcode == 0xE8 || insn->opcode == 0xE9)) { attrMask ^= ATTR_OPSIZE; if (getIDWithAttrMask(&instructionID, insn, attrMask)) return -1; } /* * JCXZ/JECXZ need special handling for 16-bit mode because the meaning * of the AdSize prefix is inverted w.r.t. 32-bit mode. */ if (insn->mode == MODE_16BIT && insn->opcode == 0xE3) { spec = specifierForUID(instructionID); /* * Check for Ii8PCRel instructions. We could alternatively do a * string-compare on the names, but this is probably cheaper. */ if (x86OperandSets[spec->operands][0].type == TYPE_REL8) { attrMask ^= ATTR_ADSIZE; if (getIDWithAttrMask(&instructionID, insn, attrMask)) return -1; } } /* The following clauses compensate for limitations of the tables. */ if ((insn->mode == MODE_16BIT || insn->isPrefix66) && !(attrMask & ATTR_OPSIZE)) { /* * The instruction tables make no distinction between instructions that * allow OpSize anywhere (i.e., 16-bit operations) and that need it in a * particular spot (i.e., many MMX operations). In general we're * conservative, but in the specific case where OpSize is present but not * in the right place we check if there's a 16-bit operation. */ const struct InstructionSpecifier *spec; uint16_t instructionIDWithOpsize; spec = specifierForUID(instructionID); if (getIDWithAttrMask(&instructionIDWithOpsize, insn, attrMask | ATTR_OPSIZE)) { /* * ModRM required with OpSize but not present; give up and return version * without OpSize set */ insn->instructionID = instructionID; insn->spec = spec; return 0; } if (is16BitEquivalent(instructionID, instructionIDWithOpsize) && (insn->mode == MODE_16BIT) ^ insn->isPrefix66) { insn->instructionID = instructionIDWithOpsize; insn->spec = specifierForUID(instructionIDWithOpsize); } else { insn->instructionID = instructionID; insn->spec = spec; } return 0; } if (insn->opcodeType == ONEBYTE && insn->opcode == 0x90 && insn->rexPrefix & 0x01) { /* * NOOP shouldn't decode as NOOP if REX.b is set. Instead * it should decode as XCHG %r8, %eax. */ const struct InstructionSpecifier *spec; uint16_t instructionIDWithNewOpcode; const struct InstructionSpecifier *specWithNewOpcode; spec = specifierForUID(instructionID); /* Borrow opcode from one of the other XCHGar opcodes */ insn->opcode = 0x91; if (getIDWithAttrMask(&instructionIDWithNewOpcode, insn, attrMask)) { insn->opcode = 0x90; insn->instructionID = instructionID; insn->spec = spec; return 0; } specWithNewOpcode = specifierForUID(instructionIDWithNewOpcode); /* Change back */ insn->opcode = 0x90; insn->instructionID = instructionIDWithNewOpcode; insn->spec = specWithNewOpcode; return 0; } insn->instructionID = instructionID; insn->spec = specifierForUID(insn->instructionID); return 0; } /* * readSIB - Consumes the SIB byte to determine addressing information for an * instruction. * * @param insn - The instruction whose SIB byte is to be read. * @return - 0 if the SIB byte was successfully read; nonzero otherwise. */ static int readSIB(struct InternalInstruction *insn) { SIBIndex sibIndexBase = SIB_INDEX_NONE; SIBBase sibBaseBase = SIB_BASE_NONE; uint8_t index, base; // dbgprintf(insn, "readSIB()"); if (insn->consumedSIB) return 0; insn->consumedSIB = true; switch (insn->addressSize) { case 2: // dbgprintf(insn, "SIB-based addressing doesn't work in 16-bit mode"); return -1; case 4: sibIndexBase = SIB_INDEX_EAX; sibBaseBase = SIB_BASE_EAX; break; case 8: sibIndexBase = SIB_INDEX_RAX; sibBaseBase = SIB_BASE_RAX; break; } if (consumeByte(insn, &insn->sib)) return -1; index = indexFromSIB(insn->sib) | (xFromREX(insn->rexPrefix) << 3); if (insn->vectorExtensionType == TYPE_EVEX) index |= v2FromEVEX4of4(insn->vectorExtensionPrefix[3]) << 4; switch (index) { case 0x4: insn->sibIndex = SIB_INDEX_NONE; break; default: insn->sibIndex = (SIBIndex)(sibIndexBase + index); if (insn->sibIndex == SIB_INDEX_sib || insn->sibIndex == SIB_INDEX_sib64) insn->sibIndex = SIB_INDEX_NONE; break; } switch (scaleFromSIB(insn->sib)) { case 0: insn->sibScale = 1; break; case 1: insn->sibScale = 2; break; case 2: insn->sibScale = 4; break; case 3: insn->sibScale = 8; break; } base = baseFromSIB(insn->sib) | (bFromREX(insn->rexPrefix) << 3); switch (base) { case 0x5: case 0xd: switch (modFromModRM(insn->modRM)) { case 0x0: insn->eaDisplacement = EA_DISP_32; insn->sibBase = SIB_BASE_NONE; break; case 0x1: insn->eaDisplacement = EA_DISP_8; insn->sibBase = (SIBBase)(sibBaseBase + base); break; case 0x2: insn->eaDisplacement = EA_DISP_32; insn->sibBase = (SIBBase)(sibBaseBase + base); break; case 0x3: //debug("Cannot have Mod = 0b11 and a SIB byte"); return -1; } break; default: insn->sibBase = (SIBBase)(sibBaseBase + base); break; } return 0; } /* * readDisplacement - Consumes the displacement of an instruction. * * @param insn - The instruction whose displacement is to be read. * @return - 0 if the displacement byte was successfully read; nonzero * otherwise. */ static int readDisplacement(struct InternalInstruction *insn) { int8_t d8; int16_t d16; int32_t d32; // dbgprintf(insn, "readDisplacement()"); if (insn->consumedDisplacement) return 0; insn->consumedDisplacement = true; insn->displacementOffset = (uint8_t)(insn->readerCursor - insn->startLocation); switch (insn->eaDisplacement) { case EA_DISP_NONE: insn->consumedDisplacement = false; break; case EA_DISP_8: if (consumeInt8(insn, &d8)) return -1; insn->displacement = d8; break; case EA_DISP_16: if (consumeInt16(insn, &d16)) return -1; insn->displacement = d16; break; case EA_DISP_32: if (consumeInt32(insn, &d32)) return -1; insn->displacement = d32; break; } insn->consumedDisplacement = true; return 0; } /* * readModRM - Consumes all addressing information (ModR/M byte, SIB byte, and * displacement) for an instruction and interprets it. * * @param insn - The instruction whose addressing information is to be read. * @return - 0 if the information was successfully read; nonzero otherwise. */ static int readModRM(struct InternalInstruction *insn) { uint8_t mod, rm, reg; // dbgprintf(insn, "readModRM()"); // already got ModRM byte? if (insn->consumedModRM) return 0; if (consumeByte(insn, &insn->modRM)) return -1; // mark that we already got ModRM insn->consumedModRM = true; // save original ModRM for later reference insn->orgModRM = insn->modRM; // handle MOVcr, MOVdr, MOVrc, MOVrd by pretending they have MRM.mod = 3 if ((insn->firstByte == 0x0f && insn->opcodeType == TWOBYTE) && (insn->opcode >= 0x20 && insn->opcode <= 0x23 )) insn->modRM |= 0xC0; mod = modFromModRM(insn->modRM); rm = rmFromModRM(insn->modRM); reg = regFromModRM(insn->modRM); /* * This goes by insn->registerSize to pick the correct register, which messes * up if we're using (say) XMM or 8-bit register operands. That gets fixed in * fixupReg(). */ switch (insn->registerSize) { case 2: insn->regBase = MODRM_REG_AX; insn->eaRegBase = EA_REG_AX; break; case 4: insn->regBase = MODRM_REG_EAX; insn->eaRegBase = EA_REG_EAX; break; case 8: insn->regBase = MODRM_REG_RAX; insn->eaRegBase = EA_REG_RAX; break; } reg |= rFromREX(insn->rexPrefix) << 3; rm |= bFromREX(insn->rexPrefix) << 3; if (insn->vectorExtensionType == TYPE_EVEX) { reg |= r2FromEVEX2of4(insn->vectorExtensionPrefix[1]) << 4; rm |= xFromEVEX2of4(insn->vectorExtensionPrefix[1]) << 4; } insn->reg = (Reg)(insn->regBase + reg); switch (insn->addressSize) { case 2: insn->eaBaseBase = EA_BASE_BX_SI; switch (mod) { case 0x0: if (rm == 0x6) { insn->eaBase = EA_BASE_NONE; insn->eaDisplacement = EA_DISP_16; if (readDisplacement(insn)) return -1; } else { insn->eaBase = (EABase)(insn->eaBaseBase + rm); insn->eaDisplacement = EA_DISP_NONE; } break; case 0x1: insn->eaBase = (EABase)(insn->eaBaseBase + rm); insn->eaDisplacement = EA_DISP_8; insn->displacementSize = 1; if (readDisplacement(insn)) return -1; break; case 0x2: insn->eaBase = (EABase)(insn->eaBaseBase + rm); insn->eaDisplacement = EA_DISP_16; if (readDisplacement(insn)) return -1; break; case 0x3: insn->eaBase = (EABase)(insn->eaRegBase + rm); insn->eaDisplacement = EA_DISP_NONE; if (readDisplacement(insn)) return -1; break; } break; case 4: case 8: insn->eaBaseBase = (insn->addressSize == 4 ? EA_BASE_EAX : EA_BASE_RAX); switch (mod) { case 0x0: insn->eaDisplacement = EA_DISP_NONE; /* readSIB may override this */ switch (rm) { case 0x14: case 0x4: case 0xc: /* in case REXW.b is set */ insn->eaBase = (insn->addressSize == 4 ? EA_BASE_sib : EA_BASE_sib64); if (readSIB(insn) || readDisplacement(insn)) return -1; break; case 0x5: case 0xd: insn->eaBase = EA_BASE_NONE; insn->eaDisplacement = EA_DISP_32; if (readDisplacement(insn)) return -1; break; default: insn->eaBase = (EABase)(insn->eaBaseBase + rm); break; } break; case 0x1: insn->displacementSize = 1; /* FALLTHROUGH */ case 0x2: insn->eaDisplacement = (mod == 0x1 ? EA_DISP_8 : EA_DISP_32); switch (rm) { case 0x14: case 0x4: case 0xc: /* in case REXW.b is set */ insn->eaBase = EA_BASE_sib; if (readSIB(insn) || readDisplacement(insn)) return -1; break; default: insn->eaBase = (EABase)(insn->eaBaseBase + rm); if (readDisplacement(insn)) return -1; break; } break; case 0x3: insn->eaDisplacement = EA_DISP_NONE; insn->eaBase = (EABase)(insn->eaRegBase + rm); break; } break; } /* switch (insn->addressSize) */ return 0; } #define GENERIC_FIXUP_FUNC(name, base, prefix) \ static uint8_t name(struct InternalInstruction *insn, \ OperandType type, \ uint8_t index, \ uint8_t *valid) { \ *valid = 1; \ switch (type) { \ case TYPE_R8: \ insn->operandSize = 1; \ break; \ case TYPE_R16: \ insn->operandSize = 2; \ break; \ case TYPE_R32: \ insn->operandSize = 4; \ break; \ case TYPE_R64: \ insn->operandSize = 8; \ break; \ case TYPE_XMM512: \ insn->operandSize = 64; \ break; \ case TYPE_XMM256: \ insn->operandSize = 32; \ break; \ case TYPE_XMM128: \ insn->operandSize = 16; \ break; \ case TYPE_XMM64: \ insn->operandSize = 8; \ break; \ case TYPE_XMM32: \ insn->operandSize = 4; \ break; \ case TYPE_XMM: \ insn->operandSize = 2; \ break; \ case TYPE_MM64: \ insn->operandSize = 8; \ break; \ case TYPE_MM32: \ insn->operandSize = 4; \ break; \ case TYPE_MM: \ insn->operandSize = 2; \ break; \ case TYPE_CONTROLREG: \ insn->operandSize = 4; \ break; \ default: break; \ } \ switch (type) { \ default: \ *valid = 0; \ return 0; \ case TYPE_Rv: \ return (uint8_t)(base + index); \ case TYPE_R8: \ if (insn->rexPrefix && \ index >= 4 && index <= 7) { \ return prefix##_SPL + (index - 4); \ } else { \ return prefix##_AL + index; \ } \ case TYPE_R16: \ return prefix##_AX + index; \ case TYPE_R32: \ return prefix##_EAX + index; \ case TYPE_R64: \ return prefix##_RAX + index; \ case TYPE_XMM512: \ return prefix##_ZMM0 + index; \ case TYPE_XMM256: \ return prefix##_YMM0 + index; \ case TYPE_XMM128: \ case TYPE_XMM64: \ case TYPE_XMM32: \ case TYPE_XMM: \ return prefix##_XMM0 + index; \ case TYPE_VK1: \ case TYPE_VK8: \ case TYPE_VK16: \ if (index > 7) \ *valid = 0; \ return prefix##_K0 + index; \ case TYPE_MM64: \ case TYPE_MM32: \ case TYPE_MM: \ return prefix##_MM0 + (index & 7); \ case TYPE_SEGMENTREG: \ if (index > 5) \ *valid = 0; \ return prefix##_ES + index; \ case TYPE_DEBUGREG: \ if (index > 7) \ *valid = 0; \ return prefix##_DR0 + index; \ case TYPE_CONTROLREG: \ return prefix##_CR0 + index; \ } \ } /* * fixup*Value - Consults an operand type to determine the meaning of the * reg or R/M field. If the operand is an XMM operand, for example, an * operand would be XMM0 instead of AX, which readModRM() would otherwise * misinterpret it as. * * @param insn - The instruction containing the operand. * @param type - The operand type. * @param index - The existing value of the field as reported by readModRM(). * @param valid - The address of a uint8_t. The target is set to 1 if the * field is valid for the register class; 0 if not. * @return - The proper value. */ GENERIC_FIXUP_FUNC(fixupRegValue, insn->regBase, MODRM_REG) GENERIC_FIXUP_FUNC(fixupRMValue, insn->eaRegBase, EA_REG) /* * fixupReg - Consults an operand specifier to determine which of the * fixup*Value functions to use in correcting readModRM()'ss interpretation. * * @param insn - See fixup*Value(). * @param op - The operand specifier. * @return - 0 if fixup was successful; -1 if the register returned was * invalid for its class. */ static int fixupReg(struct InternalInstruction *insn, const struct OperandSpecifier *op) { uint8_t valid; // dbgprintf(insn, "fixupReg()"); switch ((OperandEncoding)op->encoding) { default: //debug("Expected a REG or R/M encoding in fixupReg"); return -1; case ENCODING_VVVV: insn->vvvv = (Reg)fixupRegValue(insn, (OperandType)op->type, insn->vvvv, &valid); if (!valid) return -1; break; case ENCODING_REG: insn->reg = (Reg)fixupRegValue(insn, (OperandType)op->type, (uint8_t)(insn->reg - insn->regBase), &valid); if (!valid) return -1; break; CASE_ENCODING_RM: if (insn->eaBase >= insn->eaRegBase) { insn->eaBase = (EABase)fixupRMValue(insn, (OperandType)op->type, (uint8_t)(insn->eaBase - insn->eaRegBase), &valid); if (!valid) return -1; } break; } return 0; } /* * readOpcodeRegister - Reads an operand from the opcode field of an * instruction and interprets it appropriately given the operand width. * Handles AddRegFrm instructions. * * @param insn - the instruction whose opcode field is to be read. * @param size - The width (in bytes) of the register being specified. * 1 means AL and friends, 2 means AX, 4 means EAX, and 8 means * RAX. * @return - 0 on success; nonzero otherwise. */ static int readOpcodeRegister(struct InternalInstruction *insn, uint8_t size) { // dbgprintf(insn, "readOpcodeRegister()"); if (size == 0) size = insn->registerSize; insn->operandSize = size; switch (size) { case 1: insn->opcodeRegister = (Reg)(MODRM_REG_AL + ((bFromREX(insn->rexPrefix) << 3) | (insn->opcode & 7))); if (insn->rexPrefix && insn->opcodeRegister >= MODRM_REG_AL + 0x4 && insn->opcodeRegister < MODRM_REG_AL + 0x8) { insn->opcodeRegister = (Reg)(MODRM_REG_SPL + (insn->opcodeRegister - MODRM_REG_AL - 4)); } break; case 2: insn->opcodeRegister = (Reg)(MODRM_REG_AX + ((bFromREX(insn->rexPrefix) << 3) | (insn->opcode & 7))); break; case 4: insn->opcodeRegister = (Reg)(MODRM_REG_EAX + ((bFromREX(insn->rexPrefix) << 3) | (insn->opcode & 7))); break; case 8: insn->opcodeRegister = (Reg)(MODRM_REG_RAX + ((bFromREX(insn->rexPrefix) << 3) | (insn->opcode & 7))); break; } return 0; } /* * readImmediate - Consumes an immediate operand from an instruction, given the * desired operand size. * * @param insn - The instruction whose operand is to be read. * @param size - The width (in bytes) of the operand. * @return - 0 if the immediate was successfully consumed; nonzero * otherwise. */ static int readImmediate(struct InternalInstruction *insn, uint8_t size) { uint8_t imm8; uint16_t imm16; uint32_t imm32; uint64_t imm64; // dbgprintf(insn, "readImmediate()"); if (insn->numImmediatesConsumed == 2) { //debug("Already consumed two immediates"); return -1; } if (size == 0) size = insn->immediateSize; else insn->immediateSize = size; insn->immediateOffset = (uint8_t)(insn->readerCursor - insn->startLocation); switch (size) { case 1: if (consumeByte(insn, &imm8)) return -1; insn->immediates[insn->numImmediatesConsumed] = imm8; break; case 2: if (consumeUInt16(insn, &imm16)) return -1; insn->immediates[insn->numImmediatesConsumed] = imm16; break; case 4: if (consumeUInt32(insn, &imm32)) return -1; insn->immediates[insn->numImmediatesConsumed] = imm32; break; case 8: if (consumeUInt64(insn, &imm64)) return -1; insn->immediates[insn->numImmediatesConsumed] = imm64; break; } insn->numImmediatesConsumed++; return 0; } /* * readVVVV - Consumes vvvv from an instruction if it has a VEX prefix. * * @param insn - The instruction whose operand is to be read. * @return - 0 if the vvvv was successfully consumed; nonzero * otherwise. */ static int readVVVV(struct InternalInstruction *insn) { int vvvv; // dbgprintf(insn, "readVVVV()"); if (insn->vectorExtensionType == TYPE_EVEX) vvvv = (v2FromEVEX4of4(insn->vectorExtensionPrefix[3]) << 4 | vvvvFromEVEX3of4(insn->vectorExtensionPrefix[2])); else if (insn->vectorExtensionType == TYPE_VEX_3B) vvvv = vvvvFromVEX3of3(insn->vectorExtensionPrefix[2]); else if (insn->vectorExtensionType == TYPE_VEX_2B) vvvv = vvvvFromVEX2of2(insn->vectorExtensionPrefix[1]); else if (insn->vectorExtensionType == TYPE_XOP) vvvv = vvvvFromXOP3of3(insn->vectorExtensionPrefix[2]); else return -1; if (insn->mode != MODE_64BIT) vvvv &= 0x7; insn->vvvv = vvvv; return 0; } /* * readMaskRegister - Reads an mask register from the opcode field of an * instruction. * * @param insn - The instruction whose opcode field is to be read. * @return - 0 on success; nonzero otherwise. */ static int readMaskRegister(struct InternalInstruction *insn) { // dbgprintf(insn, "readMaskRegister()"); if (insn->vectorExtensionType != TYPE_EVEX) return -1; insn->writemask = aaaFromEVEX4of4(insn->vectorExtensionPrefix[3]); return 0; } /* * readOperands - Consults the specifier for an instruction and consumes all * operands for that instruction, interpreting them as it goes. * * @param insn - The instruction whose operands are to be read and interpreted. * @return - 0 if all operands could be read; nonzero otherwise. */ static int readOperands(struct InternalInstruction *insn) { int index; int hasVVVV, needVVVV; int sawRegImm = 0; // printf(">>> readOperands()\n"); /* If non-zero vvvv specified, need to make sure one of the operands uses it. */ hasVVVV = !readVVVV(insn); needVVVV = hasVVVV && (insn->vvvv != 0); for (index = 0; index < X86_MAX_OPERANDS; ++index) { //printf(">>> encoding[%u] = %u\n", index, x86OperandSets[insn->spec->operands][index].encoding); switch (x86OperandSets[insn->spec->operands][index].encoding) { case ENCODING_NONE: case ENCODING_SI: case ENCODING_DI: break; case ENCODING_REG: CASE_ENCODING_RM: if (readModRM(insn)) return -1; if (fixupReg(insn, &x86OperandSets[insn->spec->operands][index])) return -1; // Apply the AVX512 compressed displacement scaling factor. if (x86OperandSets[insn->spec->operands][index].encoding != ENCODING_REG && insn->eaDisplacement == EA_DISP_8) insn->displacement *= 1 << (x86OperandSets[insn->spec->operands][index].encoding - ENCODING_RM); break; case ENCODING_CB: case ENCODING_CW: case ENCODING_CD: case ENCODING_CP: case ENCODING_CO: case ENCODING_CT: // dbgprintf(insn, "We currently don't hande code-offset encodings"); return -1; case ENCODING_IB: if (sawRegImm) { /* Saw a register immediate so don't read again and instead split the previous immediate. FIXME: This is a hack. */ insn->immediates[insn->numImmediatesConsumed] = insn->immediates[insn->numImmediatesConsumed - 1] & 0xf; ++insn->numImmediatesConsumed; break; } if (readImmediate(insn, 1)) return -1; if (x86OperandSets[insn->spec->operands][index].type == TYPE_XMM128 || x86OperandSets[insn->spec->operands][index].type == TYPE_XMM256) sawRegImm = 1; break; case ENCODING_IW: if (readImmediate(insn, 2)) return -1; break; case ENCODING_ID: if (readImmediate(insn, 4)) return -1; break; case ENCODING_IO: if (readImmediate(insn, 8)) return -1; break; case ENCODING_Iv: if (readImmediate(insn, insn->immediateSize)) return -1; break; case ENCODING_Ia: if (readImmediate(insn, insn->addressSize)) return -1; break; case ENCODING_RB: if (readOpcodeRegister(insn, 1)) return -1; break; case ENCODING_RW: if (readOpcodeRegister(insn, 2)) return -1; break; case ENCODING_RD: if (readOpcodeRegister(insn, 4)) return -1; break; case ENCODING_RO: if (readOpcodeRegister(insn, 8)) return -1; break; case ENCODING_Rv: if (readOpcodeRegister(insn, 0)) return -1; break; case ENCODING_FP: break; case ENCODING_VVVV: needVVVV = 0; /* Mark that we have found a VVVV operand. */ if (!hasVVVV) return -1; if (fixupReg(insn, &x86OperandSets[insn->spec->operands][index])) return -1; break; case ENCODING_WRITEMASK: if (readMaskRegister(insn)) return -1; break; case ENCODING_DUP: break; default: // dbgprintf(insn, "Encountered an operand with an unknown encoding."); return -1; } } /* If we didn't find ENCODING_VVVV operand, but non-zero vvvv present, fail */ if (needVVVV) return -1; return 0; } // return True if instruction is illegal to use with prefixes // This also check & fix the prefixPresent[] when a prefix is irrelevant. static bool checkPrefix(struct InternalInstruction *insn) { // LOCK prefix if (insn->isPrefixf0) { switch(insn->instructionID) { default: // invalid LOCK return true; // nop dword [rax] case X86_NOOPL: // DEC case X86_DEC16m: case X86_DEC32m: case X86_DEC64_16m: case X86_DEC64_32m: case X86_DEC64m: case X86_DEC8m: // ADC case X86_ADC16mi: case X86_ADC16mi8: case X86_ADC16mr: case X86_ADC32mi: case X86_ADC32mi8: case X86_ADC32mr: case X86_ADC64mi32: case X86_ADC64mi8: case X86_ADC64mr: case X86_ADC8mi: case X86_ADC8mr: // ADD case X86_ADD16mi: case X86_ADD16mi8: case X86_ADD16mr: case X86_ADD32mi: case X86_ADD32mi8: case X86_ADD32mr: case X86_ADD64mi32: case X86_ADD64mi8: case X86_ADD64mr: case X86_ADD8mi: case X86_ADD8mr: // AND case X86_AND16mi: case X86_AND16mi8: case X86_AND16mr: case X86_AND32mi: case X86_AND32mi8: case X86_AND32mr: case X86_AND64mi32: case X86_AND64mi8: case X86_AND64mr: case X86_AND8mi: case X86_AND8mr: // BTC case X86_BTC16mi8: case X86_BTC16mr: case X86_BTC32mi8: case X86_BTC32mr: case X86_BTC64mi8: case X86_BTC64mr: // BTR case X86_BTR16mi8: case X86_BTR16mr: case X86_BTR32mi8: case X86_BTR32mr: case X86_BTR64mi8: case X86_BTR64mr: // BTS case X86_BTS16mi8: case X86_BTS16mr: case X86_BTS32mi8: case X86_BTS32mr: case X86_BTS64mi8: case X86_BTS64mr: // CMPXCHG case X86_CMPXCHG16B: case X86_CMPXCHG16rm: case X86_CMPXCHG32rm: case X86_CMPXCHG64rm: case X86_CMPXCHG8rm: case X86_CMPXCHG8B: // INC case X86_INC16m: case X86_INC32m: case X86_INC64_16m: case X86_INC64_32m: case X86_INC64m: case X86_INC8m: // NEG case X86_NEG16m: case X86_NEG32m: case X86_NEG64m: case X86_NEG8m: // NOT case X86_NOT16m: case X86_NOT32m: case X86_NOT64m: case X86_NOT8m: // OR case X86_OR16mi: case X86_OR16mi8: case X86_OR16mr: case X86_OR32mi: case X86_OR32mi8: case X86_OR32mr: case X86_OR32mrLocked: case X86_OR64mi32: case X86_OR64mi8: case X86_OR64mr: case X86_OR8mi: case X86_OR8mr: // SBB case X86_SBB16mi: case X86_SBB16mi8: case X86_SBB16mr: case X86_SBB32mi: case X86_SBB32mi8: case X86_SBB32mr: case X86_SBB64mi32: case X86_SBB64mi8: case X86_SBB64mr: case X86_SBB8mi: case X86_SBB8mr: // SUB case X86_SUB16mi: case X86_SUB16mi8: case X86_SUB16mr: case X86_SUB32mi: case X86_SUB32mi8: case X86_SUB32mr: case X86_SUB64mi32: case X86_SUB64mi8: case X86_SUB64mr: case X86_SUB8mi: case X86_SUB8mr: // XADD case X86_XADD16rm: case X86_XADD32rm: case X86_XADD64rm: case X86_XADD8rm: // XCHG case X86_XCHG16rm: case X86_XCHG32rm: case X86_XCHG64rm: case X86_XCHG8rm: // XOR case X86_XOR16mi: case X86_XOR16mi8: case X86_XOR16mr: case X86_XOR32mi: case X86_XOR32mi8: case X86_XOR32mr: case X86_XOR64mi32: case X86_XOR64mi8: case X86_XOR64mr: case X86_XOR8mi: case X86_XOR8mr: // this instruction can be used with LOCK prefix return false; } } // REPNE prefix if (insn->isPrefixf2) { // 0xf2 can be a part of instruction encoding, but not really a prefix. // In such a case, clear it. if (insn->twoByteEscape == 0x0f) { insn->prefix0 = 0; } } // no invalid prefixes return false; } /* * decodeInstruction - Reads and interprets a full instruction provided by the * user. * * @param insn - A pointer to the instruction to be populated. Must be * pre-allocated. * @param reader - The function to be used to read the instruction's bytes. * @param readerArg - A generic argument to be passed to the reader to store * any internal state. * @param startLoc - The address (in the reader's address space) of the first * byte in the instruction. * @param mode - The mode (real mode, IA-32e, or IA-32e in 64-bit mode) to * decode the instruction in. * @return - 0 if instruction is valid; nonzero if not. */ int decodeInstruction(struct InternalInstruction *insn, byteReader_t reader, const void *readerArg, uint64_t startLoc, DisassemblerMode mode) { insn->reader = reader; insn->readerArg = readerArg; insn->startLocation = startLoc; insn->readerCursor = startLoc; insn->mode = mode; if (readPrefixes(insn) || readOpcode(insn) || getID(insn) || insn->instructionID == 0 || checkPrefix(insn) || readOperands(insn)) return -1; insn->length = (size_t)(insn->readerCursor - insn->startLocation); // instruction length must be <= 15 to be valid if (insn->length > 15) return -1; if (insn->operandSize == 0) insn->operandSize = insn->registerSize; insn->operands = &x86OperandSets[insn->spec->operands][0]; // dbgprintf(insn, "Read from 0x%llx to 0x%llx: length %zu", // startLoc, insn->readerCursor, insn->length); //if (insn->length > 15) // dbgprintf(insn, "Instruction exceeds 15-byte limit"); #if 0 printf("\n>>> x86OperandSets = %lu\n", sizeof(x86OperandSets)); printf(">>> x86DisassemblerInstrSpecifiers = %lu\n", sizeof(x86DisassemblerInstrSpecifiers)); printf(">>> x86DisassemblerContexts = %lu\n", sizeof(x86DisassemblerContexts)); printf(">>> modRMTable = %lu\n", sizeof(modRMTable)); printf(">>> x86DisassemblerOneByteOpcodes = %lu\n", sizeof(x86DisassemblerOneByteOpcodes)); printf(">>> x86DisassemblerTwoByteOpcodes = %lu\n", sizeof(x86DisassemblerTwoByteOpcodes)); printf(">>> x86DisassemblerThreeByte38Opcodes = %lu\n", sizeof(x86DisassemblerThreeByte38Opcodes)); printf(">>> x86DisassemblerThreeByte3AOpcodes = %lu\n", sizeof(x86DisassemblerThreeByte3AOpcodes)); printf(">>> x86DisassemblerThreeByteA6Opcodes = %lu\n", sizeof(x86DisassemblerThreeByteA6Opcodes)); printf(">>> x86DisassemblerThreeByteA7Opcodes= %lu\n", sizeof(x86DisassemblerThreeByteA7Opcodes)); printf(">>> x86DisassemblerXOP8Opcodes = %lu\n", sizeof(x86DisassemblerXOP8Opcodes)); printf(">>> x86DisassemblerXOP9Opcodes = %lu\n", sizeof(x86DisassemblerXOP9Opcodes)); printf(">>> x86DisassemblerXOPAOpcodes = %lu\n\n", sizeof(x86DisassemblerXOPAOpcodes)); #endif return 0; } #endif