zydis/include/Zydis/Decoder.h

/***************************************************************************************************

  Zyan Disassembler Library (Zydis)

  Original Author : Florian Bernd

 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.

***************************************************************************************************/

/**
 * @file
 * @brief   Functions for decoding instructions.
 */

#ifndef ZYDIS_DECODER_H
#define ZYDIS_DECODER_H

#include <Zydis/CommonTypes.h>
#include <Zydis/DecoderTypes.h>
#include <Zydis/Defines.h>
#include <Zydis/Status.h>

#ifdef __cplusplus
extern "C" {
#endif

/* ============================================================================================== */
/* Enums and types                                                                                */
/* ============================================================================================== */

/* ---------------------------------------------------------------------------------------------- */
/* Decoder mode                                                                                   */
/* ---------------------------------------------------------------------------------------------- */

/**
 * @brief   Defines the @c ZydisDecoderMode datatype.
 */
typedef uint8_t ZydisDecoderMode;

/**
 * @brief   Values that represent decoder-modes.
 */
enum ZydisDecoderModes
{
    ZYDIS_DECODER_MODE_INVALID,
    /**
     * @brief   Enables minimal instruction decoding without semantic analysis.
     * 
     * This mode provides access to the mnemonic, the instruction-length, the effective 
     * operand-size, the effective address-width, some attributes (e.g. `ZYDIS_ATTRIB_IS_RELATIVE`) 
     * and all of the information in the `raw` field of the `ZydisDecodedInstruction` struct.
     * 
     * Operands, most attributes and other specific information (like AVX info) are not 
     * accessible in this mode.
     */
    ZYDIS_DECODER_MODE_MINIMAL,
    /**
     * @brief   Enables the AMD-branch mode.
     * 
     * Intel ignores the operand-size override-prefix (`0x66`) for all branches with 32-bit 
     * immediates and forces the operand-size of the instruction to 64-bit in 64-bit mode.
     * In AMD-branch mode `0x66` is not ignored and changes the operand-size and the size of the
     * immediate to 16-bit.
     */
    ZYDIS_DECODER_MODE_AMD_BRANCHES,
    /**
     * @brief   Enables the MPX mode.
     * 
     * The MPX isa-extension reuses (overrides) some of the widenop instruction opcodes. 
     * 
     * This mode is enabled by default. 
     */
    ZYDIS_DECODER_MODE_MPX,
    /**
     * @brief   Enables the CET mode.
     * 
     * The CET isa-extension reuses (overrides) some of the widenop instruction opcodes. 
     * 
     * This mode is enabled by default.  
     */
    ZYDIS_DECODER_MODE_CET,
    /**
     * @brief   Enables the LZCNT mode.
     * 
     * The LZCNT isa-extension reuses (overrides) some of the widenop instruction opcodes.
     * 
     * This mode is enabled by default.   
     */
    ZYDIS_DECODER_MODE_LZCNT,
    /**
     * @brief   Enables the TZCNT mode.
     * 
     * The TZCNT isa-extension reuses (overrides) some of the widenop instruction opcodes.  
     * 
     * This mode is enabled by default. 
     */
    ZYDIS_DECODER_MODE_TZCNT,
    /**
     * @brief   Maximum value of this enum.
     */
    ZYDIS_DECODER_MODE_MAX_VALUE = ZYDIS_DECODER_MODE_TZCNT
};

/* ---------------------------------------------------------------------------------------------- */
/* Decoder struct                                                                                 */
/* ---------------------------------------------------------------------------------------------- */

/**
 * @brief   Defines the @c ZydisDecoder struct.
 */
typedef struct ZydisDecoder_
{
    ZydisMachineMode machineMode;
    ZydisAddressWidth addressWidth;
    ZydisBool decoderMode[ZYDIS_DECODER_MODE_MAX_VALUE + 1];
} ZydisDecoder;

/* ---------------------------------------------------------------------------------------------- */

/* ============================================================================================== */
/* Exported functions                                                                             */
/* ============================================================================================== */

/**
 * @brief   Initializes the given @c ZydisDecoder instance.
 *
 * @param   decoder         A pointer to the @c ZydisDecoder instance.
 * @param   machineMode     The machine mode.
 * @param   addressWidth    The address width.
 *
 * @return  A zydis status code.
 */
ZYDIS_EXPORT ZydisStatus ZydisDecoderInit(ZydisDecoder* decoder, ZydisMachineMode machineMode, 
    ZydisAddressWidth addressWidth);

/**
 * @brief   Enables or disables the specified decoder-mode.
 *
 * @param   decoder A pointer to the @c ZydisDecoder instance.
 * @param   mode    The decoder mode.
 * @param   enabled `ZYDIS_TRUE` to enable, or `ZYDIS_FALSE` to disable the specified decoder-mode.
 *
 * @return  A zydis status code.
 */
ZYDIS_EXPORT ZydisStatus ZydisDecoderEnableMode(ZydisDecoder* decoder, ZydisDecoderMode mode,
    ZydisBool enabled);

/**
 * @brief   Decodes the instruction in the given input @c buffer.
 *
 * @param   decoder             A pointer to the @c ZydisDecoder instance.
 * @param   buffer              A pointer to the input buffer.
 * @param   bufferLen           The length of the input buffer.
 * @param   instructionPointer  The instruction-pointer.
 * @param   instruction         A pointer to the @c ZydisDecodedInstruction struct, that receives 
 *                              the details about the decoded instruction.
 *
 * @return  A zydis status code. 
 */
ZYDIS_EXPORT ZydisStatus ZydisDecoderDecodeBuffer(const ZydisDecoder* decoder, 
    const void* buffer, size_t bufferLen, uint64_t instructionPointer, 
    ZydisDecodedInstruction* instruction);

/* ============================================================================================== */

#ifdef __cplusplus
}
#endif

#endif /* ZYDIS_DECODER_H */