arch/PowerPC/PPCDisassembler.c

//===------ PPCDisassembler.cpp - Disassembler for PowerPC ------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

/* Capstone Disassembly Engine */
/* By Nguyen Anh Quynh <aquynh@gmail.com>, 2013-2014 */

#ifdef CAPSTONE_HAS_POWERPC

#include <stdio.h>	// DEBUG
#include <stdlib.h>

#include "../../cs_priv.h"

#include "../../MCInst.h"
#include "../../MCInstrDesc.h"
#include "../../MCFixedLenDisassembler.h"
#include "../../MCRegisterInfo.h"
#include "../../MCDisassembler.h"
#include "../../MathExtras.h"

#define GET_REGINFO_ENUM
#include "PPCGenRegisterInfo.inc"


// FIXME: These can be generated by TableGen from the existing register
// encoding values!

static const unsigned CRRegs[] = {
	PPC_CR0, PPC_CR1, PPC_CR2, PPC_CR3,
	PPC_CR4, PPC_CR5, PPC_CR6, PPC_CR7
};

static const unsigned CRBITRegs[] = {
	PPC_CR0LT, PPC_CR0GT, PPC_CR0EQ, PPC_CR0UN,
	PPC_CR1LT, PPC_CR1GT, PPC_CR1EQ, PPC_CR1UN,
	PPC_CR2LT, PPC_CR2GT, PPC_CR2EQ, PPC_CR2UN,
	PPC_CR3LT, PPC_CR3GT, PPC_CR3EQ, PPC_CR3UN,
	PPC_CR4LT, PPC_CR4GT, PPC_CR4EQ, PPC_CR4UN,
	PPC_CR5LT, PPC_CR5GT, PPC_CR5EQ, PPC_CR5UN,
	PPC_CR6LT, PPC_CR6GT, PPC_CR6EQ, PPC_CR6UN,
	PPC_CR7LT, PPC_CR7GT, PPC_CR7EQ, PPC_CR7UN
};

static const unsigned FRegs[] = {
	PPC_F0, PPC_F1, PPC_F2, PPC_F3,
	PPC_F4, PPC_F5, PPC_F6, PPC_F7,
	PPC_F8, PPC_F9, PPC_F10, PPC_F11,
	PPC_F12, PPC_F13, PPC_F14, PPC_F15,
	PPC_F16, PPC_F17, PPC_F18, PPC_F19,
	PPC_F20, PPC_F21, PPC_F22, PPC_F23,
	PPC_F24, PPC_F25, PPC_F26, PPC_F27,
	PPC_F28, PPC_F29, PPC_F30, PPC_F31
};

static const unsigned VRegs[] = {
	PPC_V0, PPC_V1, PPC_V2, PPC_V3,
	PPC_V4, PPC_V5, PPC_V6, PPC_V7,
	PPC_V8, PPC_V9, PPC_V10, PPC_V11,
	PPC_V12, PPC_V13, PPC_V14, PPC_V15,
	PPC_V16, PPC_V17, PPC_V18, PPC_V19,
	PPC_V20, PPC_V21, PPC_V22, PPC_V23,
	PPC_V24, PPC_V25, PPC_V26, PPC_V27,
	PPC_V28, PPC_V29, PPC_V30, PPC_V31
};

static const unsigned GPRegs[] = {
	PPC_R0, PPC_R1, PPC_R2, PPC_R3,
	PPC_R4, PPC_R5, PPC_R6, PPC_R7,
	PPC_R8, PPC_R9, PPC_R10, PPC_R11,
	PPC_R12, PPC_R13, PPC_R14, PPC_R15,
	PPC_R16, PPC_R17, PPC_R18, PPC_R19,
	PPC_R20, PPC_R21, PPC_R22, PPC_R23,
	PPC_R24, PPC_R25, PPC_R26, PPC_R27,
	PPC_R28, PPC_R29, PPC_R30, PPC_R31
};

static const unsigned GP0Regs[] = {
	PPC_ZERO, PPC_R1, PPC_R2, PPC_R3,
	PPC_R4, PPC_R5, PPC_R6, PPC_R7,
	PPC_R8, PPC_R9, PPC_R10, PPC_R11,
	PPC_R12, PPC_R13, PPC_R14, PPC_R15,
	PPC_R16, PPC_R17, PPC_R18, PPC_R19,
	PPC_R20, PPC_R21, PPC_R22, PPC_R23,
	PPC_R24, PPC_R25, PPC_R26, PPC_R27,
	PPC_R28, PPC_R29, PPC_R30, PPC_R31
};

static const unsigned G8Regs[] = {
	PPC_X0, PPC_X1, PPC_X2, PPC_X3,
	PPC_X4, PPC_X5, PPC_X6, PPC_X7,
	PPC_X8, PPC_X9, PPC_X10, PPC_X11,
	PPC_X12, PPC_X13, PPC_X14, PPC_X15,
	PPC_X16, PPC_X17, PPC_X18, PPC_X19,
	PPC_X20, PPC_X21, PPC_X22, PPC_X23,
	PPC_X24, PPC_X25, PPC_X26, PPC_X27,
	PPC_X28, PPC_X29, PPC_X30, PPC_X31
};

static uint64_t getFeatureBits(int feature)
{
	// enable all features
	return (uint64_t)-1;
}

static DecodeStatus decodeRegisterClass(MCInst *Inst, uint64_t RegNo,
		const unsigned *Regs)
{
	// assert(RegNo < N && "Invalid register number");
	MCInst_addOperand(Inst, MCOperand_CreateReg(Regs[RegNo]));
	return MCDisassembler_Success;
}

static DecodeStatus DecodeCRRCRegisterClass(MCInst *Inst, uint64_t RegNo,
		uint64_t Address,
		const void *Decoder)
{
	return decodeRegisterClass(Inst, RegNo, CRRegs);
}

static DecodeStatus DecodeCRBITRCRegisterClass(MCInst *Inst, uint64_t RegNo,
		uint64_t Address,
		const void *Decoder)
{
	return decodeRegisterClass(Inst, RegNo, CRBITRegs);
}

static DecodeStatus DecodeF4RCRegisterClass(MCInst *Inst, uint64_t RegNo,
		uint64_t Address,
		const void *Decoder)
{
	return decodeRegisterClass(Inst, RegNo, FRegs);
}

static DecodeStatus DecodeF8RCRegisterClass(MCInst *Inst, uint64_t RegNo,
		uint64_t Address,
		const void *Decoder)
{
	return decodeRegisterClass(Inst, RegNo, FRegs);
}

static DecodeStatus DecodeVRRCRegisterClass(MCInst *Inst, uint64_t RegNo,
		uint64_t Address,
		const void *Decoder)
{
	return decodeRegisterClass(Inst, RegNo, VRegs);
}

static DecodeStatus DecodeGPRCRegisterClass(MCInst *Inst, uint64_t RegNo,
		uint64_t Address,
		const void *Decoder)
{
	return decodeRegisterClass(Inst, RegNo, GPRegs);
}

static DecodeStatus DecodeGPRC_NOR0RegisterClass(MCInst *Inst, uint64_t RegNo,
		uint64_t Address,
		const void *Decoder)
{
	return decodeRegisterClass(Inst, RegNo, GP0Regs);
}

static DecodeStatus DecodeG8RCRegisterClass(MCInst *Inst, uint64_t RegNo,
		uint64_t Address,
		const void *Decoder)
{
	return decodeRegisterClass(Inst, RegNo, G8Regs);
}

#define DecodePointerLikeRegClass0 DecodeGPRCRegisterClass
#define DecodePointerLikeRegClass1 DecodeGPRC_NOR0RegisterClass

static DecodeStatus decodeUImmOperand(MCInst *Inst, uint64_t Imm,
		int64_t Address, const void *Decoder, unsigned N)
{
	//assert(isUInt<N>(Imm) && "Invalid immediate");
	MCInst_addOperand(Inst, MCOperand_CreateImm(Imm));
	return MCDisassembler_Success;
}

static DecodeStatus decodeSImmOperand(MCInst *Inst, uint64_t Imm,
		int64_t Address, const void *Decoder, unsigned N)
{
	// assert(isUInt<N>(Imm) && "Invalid immediate");
	MCInst_addOperand(Inst, MCOperand_CreateImm(SignExtend64(Imm, N)));
	return MCDisassembler_Success;
}


#define GET_INSTRINFO_ENUM
#include "PPCGenInstrInfo.inc"

static DecodeStatus decodeMemRIOperands(MCInst *Inst, uint64_t Imm,
		int64_t Address, const void *Decoder)
{
	// Decode the memri field (imm, reg), which has the low 16-bits as the
	// displacement and the next 5 bits as the register #.

	uint64_t Base = Imm >> 16;
	uint64_t Disp = Imm & 0xFFFF;

	// assert(Base < 32 && "Invalid base register");

	switch (MCInst_getOpcode(Inst)) {
		default: break;
		case PPC_LBZU:
		case PPC_LHAU:
		case PPC_LHZU:
		case PPC_LWZU:
		case PPC_LFSU:
		case PPC_LFDU:
				 // Add the tied output operand.
				 MCInst_addOperand(Inst, MCOperand_CreateReg(GP0Regs[Base]));
				 break;
		case PPC_STBU:
		case PPC_STHU:
		case PPC_STWU:
		case PPC_STFSU:
		case PPC_STFDU:
				 MCInst_insert(Inst, 0, MCOperand_CreateReg(GP0Regs[Base]));
				 break;
	}

	MCInst_addOperand(Inst, MCOperand_CreateImm(SignExtend64(Disp, 16)));
	MCInst_addOperand(Inst, MCOperand_CreateReg(GP0Regs[Base]));
	return MCDisassembler_Success;
}

static DecodeStatus decodeMemRIXOperands(MCInst *Inst, uint64_t Imm,
		int64_t Address, const void *Decoder)
{
	// Decode the memrix field (imm, reg), which has the low 14-bits as the
	// displacement and the next 5 bits as the register #.

	uint64_t Base = Imm >> 14;
	uint64_t Disp = Imm & 0x3FFF;

	// assert(Base < 32 && "Invalid base register");

	if (MCInst_getOpcode(Inst) == PPC_LDU)
		// Add the tied output operand.
		MCInst_addOperand(Inst, MCOperand_CreateReg(GP0Regs[Base]));
	else if (MCInst_getOpcode(Inst) == PPC_STDU)
		MCInst_insert(Inst, 0, MCOperand_CreateReg(GP0Regs[Base]));

	MCInst_addOperand(Inst, MCOperand_CreateImm(SignExtend64(Disp << 2, 16)));
	MCInst_addOperand(Inst, MCOperand_CreateReg(GP0Regs[Base]));
	return MCDisassembler_Success;
}

static DecodeStatus decodeCRBitMOperand(MCInst *Inst, uint64_t Imm,
		int64_t Address, const void *Decoder)
{
	// The cr bit encoding is 0x80 >> cr_reg_num.

	unsigned Zeros = CountTrailingZeros_64(Imm);
	// assert(Zeros < 8 && "Invalid CR bit value");

	MCInst_addOperand(Inst, MCOperand_CreateReg(CRRegs[7 - Zeros]));
	return MCDisassembler_Success;
}

#include "PPCGenDisassemblerTables.inc"

static DecodeStatus getInstruction(MCInst *MI,
		const uint8_t *code, size_t code_len,
		uint16_t *Size,
		uint64_t Address, MCRegisterInfo *MRI)
{
	uint32_t insn;
	DecodeStatus result;
	// Get the four bytes of the instruction.
	if (code_len < 4) {
		// not enough data
		*Size = 0;
		return MCDisassembler_Fail;
	}

	// The instruction is big-endian encoded.
	if (MI->csh->mode & CS_MODE_BIG_ENDIAN)
		insn = (code[0] << 24) | (code[1] << 16) |
			(code[2] <<  8) | (code[3] <<  0);
	else
		insn = (code[3] << 24) | (code[2] << 16) |
			(code[1] <<  8) | (code[0] <<  0);

	result = decodeInstruction_4(DecoderTable32, MI, insn, Address, 4);
	if (result != MCDisassembler_Fail) {
		*Size = 4;
		return result;
	}

	// report error
	MCInst_clear(MI);
	*Size = 0;
	return MCDisassembler_Fail;
}

bool PPC_getInstruction(csh ud, const uint8_t *code, size_t code_len,
		MCInst *instr, uint16_t *size, uint64_t address, void *info)
{
	DecodeStatus status = getInstruction(instr,
			code, code_len,
			size,
			address, (MCRegisterInfo *)info);

	return status == MCDisassembler_Success;
}

#define GET_REGINFO_MC_DESC
#include "PPCGenRegisterInfo.inc"
void PPC_init(MCRegisterInfo *MRI)
{
	/*
	   InitMCRegisterInfo( PPCRegDesc, 182, RA, PC,
	   PPCMCRegisterClasses, 15,
	   PPCRegUnitRoots,
	   138,
	   PPCRegDiffLists,
	   PPCRegStrings,
	   PPCSubRegIdxLists,
	   6,
	   PPCSubRegIdxRanges,
	   PPCRegEncodingTable);
	 */

	MCRegisterInfo_InitMCRegisterInfo(MRI, PPCRegDesc, 182,
			0, 0,
			PPCMCRegisterClasses, 15,
			0, 0,
			PPCRegDiffLists,
			0,
			PPCSubRegIdxLists, 6,
			0);
}

#endif