/*===- 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.
*
*===----------------------------------------------------------------------===*/
#include <stdarg.h> /* for va_*() */
#include <stdio.h> /* for vsnprintf() */
#include <stdlib.h> /* for exit() */
#include <string.h> /* for memset() */
#include "X86DisassemblerDecoder.h"
#include "X86GenDisassemblerTables.inc"
#define TRUE 1
#define FALSE 0
typedef int8_t bool;
#ifndef NDEBUG
#define debug(s) do { x86DisassemblerDebug(__FILE__, __LINE__, s); } while (0)
#else
#define debug(s) do { } while (0)
#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(uint8_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,
uint8_t opcode) {
const struct ContextDecision* decision = 0;
switch (type) {
case ONEBYTE:
decision = &ONEBYTE_SYM;
break;
case TWOBYTE:
decision = &TWOBYTE_SYM;
break;
case THREEBYTE_38:
decision = &THREEBYTE38_SYM;
break;
case THREEBYTE_3A:
decision = &THREEBYTE3A_SYM;
break;
}
return decision->opcodeDecisions[insnContext].modRMDecisions[opcode].
modrm_type != MODRM_ONEENTRY;
return 0;
}
/*
* 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 - 