tools/objtool/arch/x86/decode.c - arm/linux - Git at Google

 /*
  * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * as published by the Free Software Foundation; either version 2
  * of the License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */

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

 #define unlikely(cond) (cond)
 #include "insn/insn.h"
 #include "insn/inat.c"
 #include "insn/insn.c"

 #include "../../elf.h"
 #include "../../arch.h"
 #include "../../warn.h"

 static unsigned char op_to_cfi_reg[][2] = {
 	{CFI_AX, CFI_R8},
 	{CFI_CX, CFI_R9},
 	{CFI_DX, CFI_R10},
 	{CFI_BX, CFI_R11},
 	{CFI_SP, CFI_R12},
 	{CFI_BP, CFI_R13},
 	{CFI_SI, CFI_R14},
 	{CFI_DI, CFI_R15},
 };

 static int is_x86_64(struct elf *elf)
 {
 	switch (elf->ehdr.e_machine) {
 	case EM_X86_64:
 		return 1;
 	case EM_386:
 		return 0;
 	default:
 		WARN("unexpected ELF machine type %d", elf->ehdr.e_machine);
 		return -1;
 	}
 }

 bool arch_callee_saved_reg(unsigned char reg)
 {
 	switch (reg) {
 	case CFI_BP:
 	case CFI_BX:
 	case CFI_R12:
 	case CFI_R13:
 	case CFI_R14:
 	case CFI_R15:
 		return true;

 	case CFI_AX:
 	case CFI_CX:
 	case CFI_DX:
 	case CFI_SI:
 	case CFI_DI:
 	case CFI_SP:
 	case CFI_R8:
 	case CFI_R9:
 	case CFI_R10:
 	case CFI_R11:
 	case CFI_RA:
 	default:
 		return false;
 	}
 }

 int arch_decode_instruction(struct elf *elf, struct section *sec,
 			    unsigned long offset, unsigned int maxlen,
 			    unsigned int *len, unsigned char *type,
 			    unsigned long *immediate, struct stack_op *op)
 {
 	struct insn insn;
 	int x86_64, sign;
 	unsigned char op1, op2, rex = 0, rex_b = 0, rex_r = 0, rex_w = 0,
 		      rex_x = 0, modrm = 0, modrm_mod = 0, modrm_rm = 0,
 		      modrm_reg = 0, sib = 0;

 	x86_64 = is_x86_64(elf);
 	if (x86_64 == -1)
 		return -1;

 	insn_init(&insn, sec->data->d_buf + offset, maxlen, x86_64);
 	insn_get_length(&insn);

 	if (!insn_complete(&insn)) {
 		WARN_FUNC("can't decode instruction", sec, offset);
 		return -1;
 	}

 	*len = insn.length;
 	*type = INSN_OTHER;

 	if (insn.vex_prefix.nbytes)
 		return 0;

 	op1 = insn.opcode.bytes[0];
 	op2 = insn.opcode.bytes[1];

 	if (insn.rex_prefix.nbytes) {
 		rex = insn.rex_prefix.bytes[0];
 		rex_w = X86_REX_W(rex) >> 3;
 		rex_r = X86_REX_R(rex) >> 2;
 		rex_x = X86_REX_X(rex) >> 1;
 		rex_b = X86_REX_B(rex);
 	}

 	if (insn.modrm.nbytes) {
 		modrm = insn.modrm.bytes[0];
 		modrm_mod = X86_MODRM_MOD(modrm);
 		modrm_reg = X86_MODRM_REG(modrm);
 		modrm_rm = X86_MODRM_RM(modrm);
 	}

 	if (insn.sib.nbytes)
 		sib = insn.sib.bytes[0];

 	switch (op1) {

 	case 0x1:
 	case 0x29:
 		if (rex_w && !rex_b && modrm_mod == 3 && modrm_rm == 4) {

 			/* add/sub reg, %rsp */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_ADD;
 			op->src.reg = op_to_cfi_reg[modrm_reg][rex_r];
 			op->dest.type = OP_SRC_REG;
 			op->dest.reg = CFI_SP;
 		}
 		break;

 	case 0x50 ... 0x57:

 		/* push reg */
 		*type = INSN_STACK;
 		op->src.type = OP_SRC_REG;
 		op->src.reg = op_to_cfi_reg[op1 & 0x7][rex_b];
 		op->dest.type = OP_DEST_PUSH;

 		break;

 	case 0x58 ... 0x5f:

 		/* pop reg */
 		*type = INSN_STACK;
 		op->src.type = OP_SRC_POP;
 		op->dest.type = OP_DEST_REG;
 		op->dest.reg = op_to_cfi_reg[op1 & 0x7][rex_b];

 		break;

 	case 0x68:
 	case 0x6a:
 		/* push immediate */
 		*type = INSN_STACK;
 		op->src.type = OP_SRC_CONST;
 		op->dest.type = OP_DEST_PUSH;
 		break;

 	case 0x70 ... 0x7f:
 		*type = INSN_JUMP_CONDITIONAL;
 		break;

 	case 0x81:
 	case 0x83:
 		if (rex != 0x48)
 			break;

 		if (modrm == 0xe4) {
 			/* and imm, %rsp */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_AND;
 			op->src.reg = CFI_SP;
 			op->src.offset = insn.immediate.value;
 			op->dest.type = OP_DEST_REG;
 			op->dest.reg = CFI_SP;
 			break;
 		}

 		if (modrm == 0xc4)
 			sign = 1;
 		else if (modrm == 0xec)
 			sign = -1;
 		else
 			break;

 		/* add/sub imm, %rsp */
 		*type = INSN_STACK;
 		op->src.type = OP_SRC_ADD;
 		op->src.reg = CFI_SP;
 		op->src.offset = insn.immediate.value * sign;
 		op->dest.type = OP_DEST_REG;
 		op->dest.reg = CFI_SP;
 		break;

 	case 0x89:
 		if (rex_w && !rex_r && modrm_mod == 3 && modrm_reg == 4) {

 			/* mov %rsp, reg */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_REG;
 			op->src.reg = CFI_SP;
 			op->dest.type = OP_DEST_REG;
 			op->dest.reg = op_to_cfi_reg[modrm_rm][rex_b];
 			break;
 		}

 		if (rex_w && !rex_b && modrm_mod == 3 && modrm_rm == 4) {

 			/* mov reg, %rsp */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_REG;
 			op->src.reg = op_to_cfi_reg[modrm_reg][rex_r];
 			op->dest.type = OP_DEST_REG;
 			op->dest.reg = CFI_SP;
 			break;
 		}

 		/* fallthrough */
 	case 0x88:
 		if (!rex_b &&
 		    (modrm_mod == 1 || modrm_mod == 2) && modrm_rm == 5) {

 			/* mov reg, disp(%rbp) */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_REG;
 			op->src.reg = op_to_cfi_reg[modrm_reg][rex_r];
 			op->dest.type = OP_DEST_REG_INDIRECT;
 			op->dest.reg = CFI_BP;
 			op->dest.offset = insn.displacement.value;

 		} else if (rex_w && !rex_b && modrm_rm == 4 && sib == 0x24) {

 			/* mov reg, disp(%rsp) */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_REG;
 			op->src.reg = op_to_cfi_reg[modrm_reg][rex_r];
 			op->dest.type = OP_DEST_REG_INDIRECT;
 			op->dest.reg = CFI_SP;
 			op->dest.offset = insn.displacement.value;
 		}

 		break;

 	case 0x8b:
 		if (rex_w && !rex_b && modrm_mod == 1 && modrm_rm == 5) {

 			/* mov disp(%rbp), reg */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_REG_INDIRECT;
 			op->src.reg = CFI_BP;
 			op->src.offset = insn.displacement.value;
 			op->dest.type = OP_DEST_REG;
 			op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r];

 		} else if (rex_w && !rex_b && sib == 0x24 &&
 			   modrm_mod != 3 && modrm_rm == 4) {

 			/* mov disp(%rsp), reg */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_REG_INDIRECT;
 			op->src.reg = CFI_SP;
 			op->src.offset = insn.displacement.value;
 			op->dest.type = OP_DEST_REG;
 			op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r];
 		}

 		break;

 	case 0x8d:
 		if (sib == 0x24 && rex_w && !rex_b && !rex_x) {

 			*type = INSN_STACK;
 			if (!insn.displacement.value) {
 				/* lea (%rsp), reg */
 				op->src.type = OP_SRC_REG;
 			} else {
 				/* lea disp(%rsp), reg */
 				op->src.type = OP_SRC_ADD;
 				op->src.offset = insn.displacement.value;
 			}
 			op->src.reg = CFI_SP;
 			op->dest.type = OP_DEST_REG;
 			op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r];

 		} else if (rex == 0x48 && modrm == 0x65) {

 			/* lea disp(%rbp), %rsp */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_ADD;
 			op->src.reg = CFI_BP;
 			op->src.offset = insn.displacement.value;
 			op->dest.type = OP_DEST_REG;
 			op->dest.reg = CFI_SP;

 		} else if (rex == 0x49 && modrm == 0x62 &&
 			   insn.displacement.value == -8) {

 			/*
 			 * lea -0x8(%r10), %rsp
 			 *
 			 * Restoring rsp back to its original value after a
 			 * stack realignment.
 			 */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_ADD;
 			op->src.reg = CFI_R10;
 			op->src.offset = -8;
 			op->dest.type = OP_DEST_REG;
 			op->dest.reg = CFI_SP;

 		} else if (rex == 0x49 && modrm == 0x65 &&
 			   insn.displacement.value == -16) {

 			/*
 			 * lea -0x10(%r13), %rsp
 			 *
 			 * Restoring rsp back to its original value after a
 			 * stack realignment.
 			 */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_ADD;
 			op->src.reg = CFI_R13;
 			op->src.offset = -16;
 			op->dest.type = OP_DEST_REG;
 			op->dest.reg = CFI_SP;
 		}

 		break;

 	case 0x8f:
 		/* pop to mem */
 		*type = INSN_STACK;
 		op->src.type = OP_SRC_POP;
 		op->dest.type = OP_DEST_MEM;
 		break;

 	case 0x90:
 		*type = INSN_NOP;
 		break;

 	case 0x9c:
 		/* pushf */
 		*type = INSN_STACK;
 		op->src.type = OP_SRC_CONST;
 		op->dest.type = OP_DEST_PUSH;
 		break;

 	case 0x9d:
 		/* popf */
 		*type = INSN_STACK;
 		op->src.type = OP_SRC_POP;
 		op->dest.type = OP_DEST_MEM;
 		break;

 	case 0x0f:

 		if (op2 >= 0x80 && op2 <= 0x8f) {

 			*type = INSN_JUMP_CONDITIONAL;

 		} else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 ||
 			   op2 == 0x35) {

 			/* sysenter, sysret */
 			*type = INSN_CONTEXT_SWITCH;

 		} else if (op2 == 0x0b || op2 == 0xb9) {

 			/* ud2 */
 			*type = INSN_BUG;

 		} else if (op2 == 0x0d || op2 == 0x1f) {

 			/* nopl/nopw */
 			*type = INSN_NOP;

 		} else if (op2 == 0xa0 || op2 == 0xa8) {

 			/* push fs/gs */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_CONST;
 			op->dest.type = OP_DEST_PUSH;

 		} else if (op2 == 0xa1 || op2 == 0xa9) {

 			/* pop fs/gs */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_POP;
 			op->dest.type = OP_DEST_MEM;
 		}

 		break;

 	case 0xc9:
 		/*
 		 * leave
 		 *
 		 * equivalent to:
 		 * mov bp, sp
 		 * pop bp
 		 */
 		*type = INSN_STACK;
 		op->dest.type = OP_DEST_LEAVE;

 		break;

 	case 0xe3:
 		/* jecxz/jrcxz */
 		*type = INSN_JUMP_CONDITIONAL;
 		break;

 	case 0xe9:
 	case 0xeb:
 		*type = INSN_JUMP_UNCONDITIONAL;
 		break;

 	case 0xc2:
 	case 0xc3:
 		*type = INSN_RETURN;
 		break;

 	case 0xca: /* retf */
 	case 0xcb: /* retf */
 	case 0xcf: /* iret */
 		*type = INSN_CONTEXT_SWITCH;
 		break;

 	case 0xe8:
 		*type = INSN_CALL;
 		break;

 	case 0xff:
 		if (modrm_reg == 2 || modrm_reg == 3)

 			*type = INSN_CALL_DYNAMIC;

 		else if (modrm_reg == 4)

 			*type = INSN_JUMP_DYNAMIC;

 		else if (modrm_reg == 5)

 			/* jmpf */
 			*type = INSN_CONTEXT_SWITCH;

 		else if (modrm_reg == 6) {

 			/* push from mem */
 			*type = INSN_STACK;
 			op->src.type = OP_SRC_CONST;
 			op->dest.type = OP_DEST_PUSH;
 		}

 		break;

 	default:
 		break;
 	}

 	*immediate = insn.immediate.nbytes ? insn.immediate.value : 0;

 	return 0;
 }

 void arch_initial_func_cfi_state(struct cfi_state *state)
 {
 	int i;

 	for (i = 0; i < CFI_NUM_REGS; i++) {
 		state->regs[i].base = CFI_UNDEFINED;
 		state->regs[i].offset = 0;
 	}

 	/* initial CFA (call frame address) */
 	state->cfa.base = CFI_SP;
 	state->cfa.offset = 8;

 	/* initial RA (return address) */
 	state->regs[16].base = CFI_CFA;
 	state->regs[16].offset = -8;
 }
	/*
	* Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version 2
	* of the License, or (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, see <http://www.gnu.org/licenses/>.
	*/

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

	#define unlikely(cond) (cond)
	#include "insn/insn.h"
	#include "insn/inat.c"
	#include "insn/insn.c"

	#include "../../elf.h"
	#include "../../arch.h"
	#include "../../warn.h"

	static unsigned char op_to_cfi_reg[][2] = {
	{CFI_AX, CFI_R8},
	{CFI_CX, CFI_R9},
	{CFI_DX, CFI_R10},
	{CFI_BX, CFI_R11},
	{CFI_SP, CFI_R12},
	{CFI_BP, CFI_R13},
	{CFI_SI, CFI_R14},
	{CFI_DI, CFI_R15},
	};

	static int is_x86_64(struct elf *elf)
	{
	switch (elf->ehdr.e_machine) {
	case EM_X86_64:
	return 1;
	case EM_386:
	return 0;
	default:
	WARN("unexpected ELF machine type %d", elf->ehdr.e_machine);
	return -1;
	}
	}

	bool arch_callee_saved_reg(unsigned char reg)
	{
	switch (reg) {
	case CFI_BP:
	case CFI_BX:
	case CFI_R12:
	case CFI_R13:
	case CFI_R14:
	case CFI_R15:
	return true;

	case CFI_AX:
	case CFI_CX:
	case CFI_DX:
	case CFI_SI:
	case CFI_DI:
	case CFI_SP:
	case CFI_R8:
	case CFI_R9:
	case CFI_R10:
	case CFI_R11:
	case CFI_RA:
	default:
	return false;
	}
	}

	int arch_decode_instruction(struct elf elf, struct section sec,
	unsigned long offset, unsigned int maxlen,
	unsigned int len, unsigned char type,
	unsigned long immediate, struct stack_op op)
	{
	struct insn insn;
	int x86_64, sign;
	unsigned char op1, op2, rex = 0, rex_b = 0, rex_r = 0, rex_w = 0,
	rex_x = 0, modrm = 0, modrm_mod = 0, modrm_rm = 0,
	modrm_reg = 0, sib = 0;

	x86_64 = is_x86_64(elf);
	if (x86_64 == -1)
	return -1;

	insn_init(&insn, sec->data->d_buf + offset, maxlen, x86_64);
	insn_get_length(&insn);

	if (!insn_complete(&insn)) {
	WARN_FUNC("can't decode instruction", sec, offset);
	return -1;
	}

	*len = insn.length;
	*type = INSN_OTHER;

	if (insn.vex_prefix.nbytes)
	return 0;

	op1 = insn.opcode.bytes[0];
	op2 = insn.opcode.bytes[1];

	if (insn.rex_prefix.nbytes) {
	rex = insn.rex_prefix.bytes[0];
	rex_w = X86_REX_W(rex) >> 3;
	rex_r = X86_REX_R(rex) >> 2;
	rex_x = X86_REX_X(rex) >> 1;
	rex_b = X86_REX_B(rex);
	}

	if (insn.modrm.nbytes) {
	modrm = insn.modrm.bytes[0];
	modrm_mod = X86_MODRM_MOD(modrm);
	modrm_reg = X86_MODRM_REG(modrm);
	modrm_rm = X86_MODRM_RM(modrm);
	}

	if (insn.sib.nbytes)
	sib = insn.sib.bytes[0];

	switch (op1) {

	case 0x1:
	case 0x29:
	if (rex_w && !rex_b && modrm_mod == 3 && modrm_rm == 4) {

	/* add/sub reg, %rsp */
	*type = INSN_STACK;
	op->src.type = OP_SRC_ADD;
	op->src.reg = op_to_cfi_reg[modrm_reg][rex_r];
	op->dest.type = OP_SRC_REG;
	op->dest.reg = CFI_SP;
	}
	break;

	case 0x50 ... 0x57:

	/* push reg */
	*type = INSN_STACK;
	op->src.type = OP_SRC_REG;
	op->src.reg = op_to_cfi_reg[op1 & 0x7][rex_b];
	op->dest.type = OP_DEST_PUSH;

	break;

	case 0x58 ... 0x5f:

	/* pop reg */
	*type = INSN_STACK;
	op->src.type = OP_SRC_POP;
	op->dest.type = OP_DEST_REG;
	op->dest.reg = op_to_cfi_reg[op1 & 0x7][rex_b];

	break;

	case 0x68:
	case 0x6a:
	/* push immediate */
	*type = INSN_STACK;
	op->src.type = OP_SRC_CONST;
	op->dest.type = OP_DEST_PUSH;
	break;

	case 0x70 ... 0x7f:
	*type = INSN_JUMP_CONDITIONAL;
	break;

	case 0x81:
	case 0x83:
	if (rex != 0x48)
	break;

	if (modrm == 0xe4) {
	/* and imm, %rsp */
	*type = INSN_STACK;
	op->src.type = OP_SRC_AND;
	op->src.reg = CFI_SP;
	op->src.offset = insn.immediate.value;
	op->dest.type = OP_DEST_REG;
	op->dest.reg = CFI_SP;
	break;
	}

	if (modrm == 0xc4)
	sign = 1;
	else if (modrm == 0xec)
	sign = -1;
	else
	break;

	/* add/sub imm, %rsp */
	*type = INSN_STACK;
	op->src.type = OP_SRC_ADD;
	op->src.reg = CFI_SP;
	op->src.offset = insn.immediate.value * sign;
	op->dest.type = OP_DEST_REG;
	op->dest.reg = CFI_SP;
	break;

	case 0x89:
	if (rex_w && !rex_r && modrm_mod == 3 && modrm_reg == 4) {

	/* mov %rsp, reg */
	*type = INSN_STACK;
	op->src.type = OP_SRC_REG;
	op->src.reg = CFI_SP;
	op->dest.type = OP_DEST_REG;
	op->dest.reg = op_to_cfi_reg[modrm_rm][rex_b];
	break;
	}

	if (rex_w && !rex_b && modrm_mod == 3 && modrm_rm == 4) {

	/* mov reg, %rsp */
	*type = INSN_STACK;
	op->src.type = OP_SRC_REG;
	op->src.reg = op_to_cfi_reg[modrm_reg][rex_r];
	op->dest.type = OP_DEST_REG;
	op->dest.reg = CFI_SP;
	break;
	}

	/* fallthrough */
	case 0x88:
	if (!rex_b &&
	(modrm_mod == 1 \|\| modrm_mod == 2) && modrm_rm == 5) {

	/* mov reg, disp(%rbp) */
	*type = INSN_STACK;
	op->src.type = OP_SRC_REG;
	op->src.reg = op_to_cfi_reg[modrm_reg][rex_r];
	op->dest.type = OP_DEST_REG_INDIRECT;
	op->dest.reg = CFI_BP;
	op->dest.offset = insn.displacement.value;

	} else if (rex_w && !rex_b && modrm_rm == 4 && sib == 0x24) {

	/* mov reg, disp(%rsp) */
	*type = INSN_STACK;
	op->src.type = OP_SRC_REG;
	op->src.reg = op_to_cfi_reg[modrm_reg][rex_r];
	op->dest.type = OP_DEST_REG_INDIRECT;
	op->dest.reg = CFI_SP;
	op->dest.offset = insn.displacement.value;
	}

	break;

	case 0x8b:
	if (rex_w && !rex_b && modrm_mod == 1 && modrm_rm == 5) {

	/* mov disp(%rbp), reg */
	*type = INSN_STACK;
	op->src.type = OP_SRC_REG_INDIRECT;
	op->src.reg = CFI_BP;
	op->src.offset = insn.displacement.value;
	op->dest.type = OP_DEST_REG;
	op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r];

	} else if (rex_w && !rex_b && sib == 0x24 &&
	modrm_mod != 3 && modrm_rm == 4) {

	/* mov disp(%rsp), reg */
	*type = INSN_STACK;
	op->src.type = OP_SRC_REG_INDIRECT;
	op->src.reg = CFI_SP;
	op->src.offset = insn.displacement.value;
	op->dest.type = OP_DEST_REG;
	op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r];
	}

	break;

	case 0x8d:
	if (sib == 0x24 && rex_w && !rex_b && !rex_x) {

	*type = INSN_STACK;
	if (!insn.displacement.value) {
	/* lea (%rsp), reg */
	op->src.type = OP_SRC_REG;
	} else {
	/* lea disp(%rsp), reg */
	op->src.type = OP_SRC_ADD;
	op->src.offset = insn.displacement.value;
	}
	op->src.reg = CFI_SP;
	op->dest.type = OP_DEST_REG;
	op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r];

	} else if (rex == 0x48 && modrm == 0x65) {

	/* lea disp(%rbp), %rsp */
	*type = INSN_STACK;
	op->src.type = OP_SRC_ADD;
	op->src.reg = CFI_BP;
	op->src.offset = insn.displacement.value;
	op->dest.type = OP_DEST_REG;
	op->dest.reg = CFI_SP;

	} else if (rex == 0x49 && modrm == 0x62 &&
	insn.displacement.value == -8) {

	/*
	* lea -0x8(%r10), %rsp
	*
	* Restoring rsp back to its original value after a
	* stack realignment.
	*/
	*type = INSN_STACK;
	op->src.type = OP_SRC_ADD;
	op->src.reg = CFI_R10;
	op->src.offset = -8;
	op->dest.type = OP_DEST_REG;
	op->dest.reg = CFI_SP;

	} else if (rex == 0x49 && modrm == 0x65 &&
	insn.displacement.value == -16) {

	/*
	* lea -0x10(%r13), %rsp
	*
	* Restoring rsp back to its original value after a
	* stack realignment.
	*/
	*type = INSN_STACK;
	op->src.type = OP_SRC_ADD;
	op->src.reg = CFI_R13;
	op->src.offset = -16;
	op->dest.type = OP_DEST_REG;
	op->dest.reg = CFI_SP;
	}

	break;

	case 0x8f:
	/* pop to mem */
	*type = INSN_STACK;
	op->src.type = OP_SRC_POP;
	op->dest.type = OP_DEST_MEM;
	break;

	case 0x90:
	*type = INSN_NOP;
	break;

	case 0x9c:
	/* pushf */
	*type = INSN_STACK;
	op->src.type = OP_SRC_CONST;
	op->dest.type = OP_DEST_PUSH;
	break;

	case 0x9d:
	/* popf */
	*type = INSN_STACK;
	op->src.type = OP_SRC_POP;
	op->dest.type = OP_DEST_MEM;
	break;

	case 0x0f:

	if (op2 >= 0x80 && op2 <= 0x8f) {

	*type = INSN_JUMP_CONDITIONAL;

	} else if (op2 == 0x05 \|\| op2 == 0x07 \|\| op2 == 0x34 \|\|
	op2 == 0x35) {

	/* sysenter, sysret */
	*type = INSN_CONTEXT_SWITCH;

	} else if (op2 == 0x0b \|\| op2 == 0xb9) {

	/* ud2 */
	*type = INSN_BUG;

	} else if (op2 == 0x0d \|\| op2 == 0x1f) {

	/* nopl/nopw */
	*type = INSN_NOP;

	} else if (op2 == 0xa0 \|\| op2 == 0xa8) {

	/* push fs/gs */
	*type = INSN_STACK;
	op->src.type = OP_SRC_CONST;
	op->dest.type = OP_DEST_PUSH;

	} else if (op2 == 0xa1 \|\| op2 == 0xa9) {

	/* pop fs/gs */
	*type = INSN_STACK;
	op->src.type = OP_SRC_POP;
	op->dest.type = OP_DEST_MEM;
	}

	break;

	case 0xc9:
	/*
	* leave
	*
	* equivalent to:
	* mov bp, sp
	* pop bp
	*/
	*type = INSN_STACK;
	op->dest.type = OP_DEST_LEAVE;

	break;

	case 0xe3:
	/* jecxz/jrcxz */
	*type = INSN_JUMP_CONDITIONAL;
	break;

	case 0xe9:
	case 0xeb:
	*type = INSN_JUMP_UNCONDITIONAL;
	break;

	case 0xc2:
	case 0xc3:
	*type = INSN_RETURN;
	break;

	case 0xca: /* retf */
	case 0xcb: /* retf */
	case 0xcf: /* iret */
	*type = INSN_CONTEXT_SWITCH;
	break;

	case 0xe8:
	*type = INSN_CALL;
	break;

	case 0xff:
	if (modrm_reg == 2 \|\| modrm_reg == 3)

	*type = INSN_CALL_DYNAMIC;

	else if (modrm_reg == 4)

	*type = INSN_JUMP_DYNAMIC;

	else if (modrm_reg == 5)

	/* jmpf */
	*type = INSN_CONTEXT_SWITCH;

	else if (modrm_reg == 6) {

	/* push from mem */
	*type = INSN_STACK;
	op->src.type = OP_SRC_CONST;
	op->dest.type = OP_DEST_PUSH;
	}

	break;

	default:
	break;
	}

	*immediate = insn.immediate.nbytes ? insn.immediate.value : 0;

	return 0;
	}

	void arch_initial_func_cfi_state(struct cfi_state *state)
	{
	int i;

	for (i = 0; i < CFI_NUM_REGS; i++) {
	state->regs[i].base = CFI_UNDEFINED;
	state->regs[i].offset = 0;
	}

	/* initial CFA (call frame address) */
	state->cfa.base = CFI_SP;
	state->cfa.offset = 8;

	/* initial RA (return address) */
	state->regs[16].base = CFI_CFA;
	state->regs[16].offset = -8;
	}