Quelle  Decoder.c   Sprache: C

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

  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.

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

// ReSharper disable CppClangTidyClangDiagnosticImplicitFallthrough
// ReSharper disable CppClangTidyClangDiagnosticSwitchEnum
// ReSharper disable CppClangTidyClangDiagnosticCoveredSwitchDefault

// Temporarily disabled due to a LLVM issue:
// ReSharper disable CppClangTidyBugproneNarrowingConversions

#include "zydis/Zycore/LibC.h"
#include "zydis/Zydis/Decoder.h"
#include "zydis/Zydis/Status.h"
#include "zydis/Zydis/Internal/DecoderData.h"
#include "zydis/Zydis/Internal/SharedData.h"

/* ============================================================================================== */
/* Internal enums and types                                                                       */
/* ============================================================================================== */

/* ---------------------------------------------------------------------------------------------- */
/* Decoder context                                                                                */
/* ---------------------------------------------------------------------------------------------- */

/**
 * Defines the `ZydisDecoderState` struct.
 */
typedef struct ZydisDecoderState_
{
    /**
     * A pointer to the `ZydisDecoder` instance.
     */
    const ZydisDecoder* decoder;
    /**
     * A pointer to the `ZydisDecoderContext` struct.
     */
    ZydisDecoderContext* context;
    /**
     * The input buffer.
     */
    const ZyanU8* buffer;
    /**
     * The input buffer length.
     */
    ZyanUSize buffer_len;
    /**
     * Prefix information.
     */
    struct
    {
        /**
         * Signals, if the instruction has a `LOCK` prefix (`F0`).
         *
         * This prefix originally belongs to group 1, but separating it from the other ones makes
         * parsing easier for us later.
         */
        ZyanBool has_lock;
        /**
         * The effective prefix of group 1 (either `F2` or `F3`).
         */
        ZyanU8 group1;
        /**
         * The effective prefix of group 2 (`2E`, `36`, `3E`, `26`, `64` or `65`).
         */
        ZyanU8 group2;
        /**
         * The effective segment prefix.
         */
        ZyanU8 effective_segment;
        /**
         * The prefix that should be treated as the mandatory-prefix, if the
         * current instruction needs one.
         *
         * The last `F3`/`F2` prefix has precedence over previous ones and
         * `F3`/`F2` in general have precedence over `66`.
         */
        ZyanU8 mandatory_candidate;
        /**
         * The offset of the effective `LOCK` prefix.
         */
        ZyanU8 offset_lock;
        /**
         * The offset of the effective prefix in group 1.
         */
        ZyanU8 offset_group1;
        /**
         * The offset of the effective prefix in group 2.
         */
        ZyanU8 offset_group2;
        /**
         * The offset of the operand-size override prefix (`66`).
         *
         * This is the only prefix in group 3.
         */
        ZyanU8 offset_osz_override;
        /**
         * The offset of the address-size override prefix (`67`).
         *
         * This is the only prefix in group 4.
         */
        ZyanU8 offset_asz_override;
        /**
         * The offset of the effective segment prefix.
         */
        ZyanU8 offset_segment;
        /**
         * The offset of the mandatory-candidate prefix.
         */
        ZyanU8 offset_mandatory;
        /**
         * The offset of a possible `CET` `no-lock` prefix.
         */
        ZyanI8 offset_notrack;
    } prefixes;
} ZydisDecoderState;

/* ---------------------------------------------------------------------------------------------- */
/* Register encoding                                                                              */
/* ---------------------------------------------------------------------------------------------- */

/**
 * Defines the `ZydisRegisterEncoding` enum.
 */
typedef enum ZydisRegisterEncoding_
{
    ZYDIS_REG_ENCODING_INVALID,
    /**
     * The register-id is encoded as part of the opcode (bits [3..0]).
     *
     * Possible extension by:
     * - `REX.B`
     */
    ZYDIS_REG_ENCODING_OPCODE,
    /**
     * The register-id is encoded in `modrm.reg`.
     *
     * Possible extension by:
     * - `.R`
     * - `.R'` (vector only, EVEX/MVEX)
     */
    ZYDIS_REG_ENCODING_REG,
    /**
     * The register-id is encoded in `.vvvv`.
     *
     * Possible extension by:
     * - `.v'` (vector only, EVEX/MVEX).
     */
    ZYDIS_REG_ENCODING_NDSNDD,
    /**
     * The register-id is encoded in `modrm.rm`.
     *
     * Possible extension by:
     * - `.B`
     * - `.X` (vector only, EVEX/MVEX)`
     */
    ZYDIS_REG_ENCODING_RM,
    /**
     * The register-id is encoded in `modrm.rm` or `sib.base` (if `SIB` is present).
     *
     * Possible extension by:
     * - `.B`
     */
    ZYDIS_REG_ENCODING_BASE,
    /**
     * The register-id is encoded in `sib.index`.
     *
     * Possible extension by:
     * - `.X`
     */
    ZYDIS_REG_ENCODING_INDEX,
    /**
     * The register-id is encoded in `sib.index`.
     *
     * Possible extension by:
     * - `.X`
     * - `.V'` (vector only, EVEX/MVEX)
     */
    ZYDIS_REG_ENCODING_VIDX,
    /**
     * The register-id is encoded in an additional 8-bit immediate value.
     *
     * Bits [7:4] in 64-bit mode with possible extension by bit [3] (vector only), bits [7:5] for
     * all other modes.
     */
    ZYDIS_REG_ENCODING_IS4,
    /**
     * The register-id is encoded in `EVEX.aaa/MVEX.kkk`.
     */
    ZYDIS_REG_ENCODING_MASK,

    /**
     * Maximum value of this enum.
     */
    ZYDIS_REG_ENCODING_MAX_VALUE = ZYDIS_REG_ENCODING_MASK,
    /**
     * The minimum number of bits required to represent all values of this enum.
     */
    ZYDIS_REG_ENCODING_REQUIRED_BITS = ZYAN_BITS_TO_REPRESENT(ZYDIS_REG_ENCODING_MAX_VALUE)
} ZydisRegisterEncoding;

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

/* ============================================================================================== */
/* Internal functions                                                                             */
/* ============================================================================================== */

/* ---------------------------------------------------------------------------------------------- */
/* Input helper functions                                                                         */
/* ---------------------------------------------------------------------------------------------- */

/**
 * Reads one byte from the current read-position of the input data-source.
 *
 * @param   state       A pointer to the `ZydisDecoderState` struct.
 * @param   instruction A pointer to the `ZydisDecodedInstruction` struct.
 * @param   value       A pointer to the memory that receives the byte from the input data-source.
 *
 * @return  A zyan status code.
 *
 * This function may fail, if the `ZYDIS_MAX_INSTRUCTION_LENGTH` limit got exceeded, or no more
 * data is available.
 */
static ZyanStatus ZydisInputPeek(ZydisDecoderState* state,
    ZydisDecodedInstruction* instruction, ZyanU8* value)
{
    ZYAN_ASSERT(state);
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(value);

    if (instruction->length >= ZYDIS_MAX_INSTRUCTION_LENGTH)
    {
        return ZYDIS_STATUS_INSTRUCTION_TOO_LONG;
    }

    if (state->buffer_len > 0)
    {
        *value = state->buffer[0];
        return ZYAN_STATUS_SUCCESS;
    }

    return ZYDIS_STATUS_NO_MORE_DATA;
}

/**
 * Increases the read-position of the input data-source by one byte.
 *
 * @param   state       A pointer to the `ZydisDecoderState` instance
 * @param   instruction A pointer to the `ZydisDecodedInstruction` struct.
 *
 * This function is supposed to get called ONLY after a successful call of `ZydisInputPeek`.
 *
 * This function increases the `length` field of the `ZydisDecodedInstruction` struct by one.
 */
static void ZydisInputSkip(ZydisDecoderState* state, ZydisDecodedInstruction* instruction)
{
    ZYAN_ASSERT(state);
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(instruction->length < ZYDIS_MAX_INSTRUCTION_LENGTH);

    ++instruction->length;
    ++state->buffer;
    --state->buffer_len;
}

/**
 * Reads one byte from the current read-position of the input data-source and increases
 *          the read-position by one byte afterwards.
 *
 * @param   state       A pointer to the `ZydisDecoderState` struct.
 * @param   instruction A pointer to the `ZydisDecodedInstruction` struct.
 * @param   value       A pointer to the memory that receives the byte from the input data-source.
 *
 * @return  A zyan status code.
 *
 * This function acts like a subsequent call of `ZydisInputPeek` and `ZydisInputSkip`.
 */
static ZyanStatus ZydisInputNext(ZydisDecoderState* state,
    ZydisDecodedInstruction* instruction, ZyanU8* value)
{
    ZYAN_ASSERT(state);
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(value);

    if (instruction->length >= ZYDIS_MAX_INSTRUCTION_LENGTH)
    {
        return ZYDIS_STATUS_INSTRUCTION_TOO_LONG;
    }

    if (state->buffer_len > 0)
    {
        *value = state->buffer++[0];
        ++instruction->length;
        --state->buffer_len;
        return ZYAN_STATUS_SUCCESS;
    }

    return ZYDIS_STATUS_NO_MORE_DATA;
}

/**
 * Reads a variable amount of bytes from the current read-position of the input
 *          data-source and increases the read-position by specified amount of bytes afterwards.
 *
 * @param   state           A pointer to the `ZydisDecoderState` struct.
 * @param   instruction     A pointer to the `ZydisDecodedInstruction` struct.
 * @param   value           A pointer to the memory that receives the byte from the input
 *                          data-source.
 * @param   number_of_bytes The number of bytes to read from the input data-source.
 *
 * @return  A zyan status code.
 *
 * This function acts like a subsequent call of `ZydisInputPeek` and `ZydisInputSkip`.
 */
static ZyanStatus ZydisInputNextBytes(ZydisDecoderState* state,
    ZydisDecodedInstruction* instruction, ZyanU8* value, ZyanU8 number_of_bytes)
{
    ZYAN_ASSERT(state);
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(value);

    if (instruction->length + number_of_bytes > ZYDIS_MAX_INSTRUCTION_LENGTH)
    {
        return ZYDIS_STATUS_INSTRUCTION_TOO_LONG;
    }

    if (state->buffer_len >= number_of_bytes)
    {
        instruction->length += number_of_bytes;

        ZYAN_MEMCPY(value, state->buffer, number_of_bytes);
        state->buffer += number_of_bytes;
        state->buffer_len -= number_of_bytes;

        return ZYAN_STATUS_SUCCESS;
    }

    return ZYDIS_STATUS_NO_MORE_DATA;
}

/* ---------------------------------------------------------------------------------------------- */
/* Decode functions                                                                               */
/* ---------------------------------------------------------------------------------------------- */

/**
 * Decodes the `REX`-prefix.
 *
 * @param   context     A pointer to the `ZydisDecoderContext` struct.
 * @param   instruction A pointer to the `ZydisDecodedInstruction` struct.
 * @param   data        The `REX` byte.
 */
static void ZydisDecodeREX(ZydisDecoderContext* context, ZydisDecodedInstruction* instruction,
    ZyanU8 data)
{
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT((data & 0xF0) == 0x40);

    instruction->attributes |= ZYDIS_ATTRIB_HAS_REX;
    instruction->raw.rex.W   = (data >> 3) & 0x01;
    instruction->raw.rex.R   = (data >> 2) & 0x01;
    instruction->raw.rex.X   = (data >> 1) & 0x01;
    instruction->raw.rex.B   = (data >> 0) & 0x01;

    // Update internal fields
    context->vector_unified.W = instruction->raw.rex.W;
    context->vector_unified.R = instruction->raw.rex.R;
    context->vector_unified.X = instruction->raw.rex.X;
    context->vector_unified.B = instruction->raw.rex.B;
}

/**
 * Decodes the `XOP`-prefix.
 *
 * @param   context     A pointer to the `ZydisDecoderContext` struct.
 * @param   instruction A pointer to the `ZydisDecodedInstruction` struct.
 * @param   data        The `XOP` bytes.
 *
 * @return  A zyan status code.
 */
static ZyanStatus ZydisDecodeXOP(ZydisDecoderContext* context,
    ZydisDecodedInstruction* instruction, const ZyanU8 data[3])
{
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(data[0] == 0x8F);
    ZYAN_ASSERT(((data[1] >> 0) & 0x1F) >= 8);
    ZYAN_ASSERT(instruction->raw.xop.offset == instruction->length - 3);

    if (instruction->machine_mode == ZYDIS_MACHINE_MODE_REAL_16)
    {
        // XOP is invalid in 16-bit real mode
        return ZYDIS_STATUS_DECODING_ERROR;
    }

    instruction->attributes |= ZYDIS_ATTRIB_HAS_XOP;
    instruction->raw.xop.R       = (data[1] >> 7) & 0x01;
    instruction->raw.xop.X       = (data[1] >> 6) & 0x01;
    instruction->raw.xop.B       = (data[1] >> 5) & 0x01;
    instruction->raw.xop.m_mmmm  = (data[1] >> 0) & 0x1F;

    if ((instruction->raw.xop.m_mmmm < 0x08) || (instruction->raw.xop.m_mmmm > 0x0A))
    {
        // Invalid according to the AMD documentation
        return ZYDIS_STATUS_INVALID_MAP;
    }

    instruction->raw.xop.W    = (data[2] >> 7) & 0x01;
    instruction->raw.xop.vvvv = (data[2] >> 3) & 0x0F;
    instruction->raw.xop.L    = (data[2] >> 2) & 0x01;
    instruction->raw.xop.pp   = (data[2] >> 0) & 0x03;

    // Update internal fields
    context->vector_unified.W    = instruction->raw.xop.W;
    context->vector_unified.R    = 0x01 & ~instruction->raw.xop.R;
    context->vector_unified.X    = 0x01 & ~instruction->raw.xop.X;
    context->vector_unified.B    = 0x01 & ~instruction->raw.xop.B;
    context->vector_unified.L    = instruction->raw.xop.L;
    context->vector_unified.LL   = instruction->raw.xop.L;
    context->vector_unified.vvvv = (0x0F & ~instruction->raw.xop.vvvv);

    return ZYAN_STATUS_SUCCESS;
}

/**
 * Decodes the `VEX`-prefix.
 *
 * @param   context     A pointer to the `ZydisDecoderContext` struct.
 * @param   instruction A pointer to the `ZydisDecodedInstruction` struct.
 * @param   data        The `VEX` bytes.
 *
 * @return  A zyan status code.
 */
static ZyanStatus ZydisDecodeVEX(ZydisDecoderContext* context,
    ZydisDecodedInstruction* instruction, const ZyanU8 data[3])
{
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT((data[0] == 0xC4) || (data[0] == 0xC5));

    if (instruction->machine_mode == ZYDIS_MACHINE_MODE_REAL_16)
    {
        // VEX is invalid in 16-bit real mode
        return ZYDIS_STATUS_DECODING_ERROR;
    }

    instruction->attributes |= ZYDIS_ATTRIB_HAS_VEX;
    switch (data[0])
    {
    case 0xC4:
        ZYAN_ASSERT(instruction->raw.vex.offset == instruction->length - 3);
        instruction->raw.vex.size    = 3;
        instruction->raw.vex.R       = (data[1] >> 7) & 0x01;
        instruction->raw.vex.X       = (data[1] >> 6) & 0x01;
        instruction->raw.vex.B       = (data[1] >> 5) & 0x01;
        instruction->raw.vex.m_mmmm  = (data[1] >> 0) & 0x1F;
        instruction->raw.vex.W       = (data[2] >> 7) & 0x01;
        instruction->raw.vex.vvvv    = (data[2] >> 3) & 0x0F;
        instruction->raw.vex.L       = (data[2] >> 2) & 0x01;
        instruction->raw.vex.pp      = (data[2] >> 0) & 0x03;
        break;
    case 0xC5:
        ZYAN_ASSERT(instruction->raw.vex.offset == instruction->length - 2);
        instruction->raw.vex.size    = 2;
        instruction->raw.vex.R       = (data[1] >> 7) & 0x01;
        instruction->raw.vex.X       = 1;
        instruction->raw.vex.B       = 1;
        instruction->raw.vex.m_mmmm  = 1;
        instruction->raw.vex.W       = 0;
        instruction->raw.vex.vvvv    = (data[1] >> 3) & 0x0F;
        instruction->raw.vex.L       = (data[1] >> 2) & 0x01;
        instruction->raw.vex.pp      = (data[1] >> 0) & 0x03;
        break;
    default:
        ZYAN_UNREACHABLE;
    }

    // Map 0 is only valid for some KNC instructions
#ifdef ZYDIS_DISABLE_KNC
    if ((instruction->raw.vex.m_mmmm == 0) || (instruction->raw.vex.m_mmmm > 0x03))
#else
    if (instruction->raw.vex.m_mmmm > 0x03)
#endif
    {
        // Invalid according to the intel documentation
        return ZYDIS_STATUS_INVALID_MAP;
    }

    // Update internal fields
    context->vector_unified.W    = instruction->raw.vex.W;
    context->vector_unified.R    = 0x01 & ~instruction->raw.vex.R;
    context->vector_unified.X    = 0x01 & ~instruction->raw.vex.X;
    context->vector_unified.B    = 0x01 & ~instruction->raw.vex.B;
    context->vector_unified.L    = instruction->raw.vex.L;
    context->vector_unified.LL   = instruction->raw.vex.L;
    context->vector_unified.vvvv = (0x0F & ~instruction->raw.vex.vvvv);

    return ZYAN_STATUS_SUCCESS;
}

#ifndef ZYDIS_DISABLE_AVX512
/**
 * Decodes the `EVEX`-prefix.
 *
 * @param   context     A pointer to the `ZydisDecoderContext` struct.
 * @param   instruction A pointer to the `ZydisDecodedInstruction` struct.
 * @param   data        The `EVEX` bytes.
 *
 * @return  A zyan status code.
 */
static ZyanStatus ZydisDecodeEVEX(ZydisDecoderContext* context,
    ZydisDecodedInstruction* instruction, const ZyanU8 data[4])
{
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(data[0] == 0x62);
    ZYAN_ASSERT(instruction->raw.evex.offset == instruction->length - 4);

    if (instruction->machine_mode == ZYDIS_MACHINE_MODE_REAL_16)
    {
        // EVEX is invalid in 16-bit real mode
        return ZYDIS_STATUS_DECODING_ERROR;
    }

    instruction->attributes |= ZYDIS_ATTRIB_HAS_EVEX;
    instruction->raw.evex.R         = (data[1] >> 7) & 0x01;
    instruction->raw.evex.X         = (data[1] >> 6) & 0x01;
    instruction->raw.evex.B         = (data[1] >> 5) & 0x01;
    instruction->raw.evex.R2        = (data[1] >> 4) & 0x01;

    if (data[1] & 0x08)
    {
        // Invalid according to the intel documentation
        return ZYDIS_STATUS_MALFORMED_EVEX;
    }

    instruction->raw.evex.mmm       = (data[1] >> 0) & 0x07;

    if ((instruction->raw.evex.mmm == 0x00) ||
        (instruction->raw.evex.mmm == 0x04) ||
        (instruction->raw.evex.mmm == 0x07))
    {
        // Invalid according to the intel documentation
        return ZYDIS_STATUS_INVALID_MAP;
    }

    instruction->raw.evex.W         = (data[2] >> 7) & 0x01;
    instruction->raw.evex.vvvv      = (data[2] >> 3) & 0x0F;

    ZYAN_ASSERT(((data[2] >> 2) & 0x01) == 0x01);

    instruction->raw.evex.pp        = (data[2] >> 0) & 0x03;
    instruction->raw.evex.z         = (data[3] >> 7) & 0x01;
    instruction->raw.evex.L2        = (data[3] >> 6) & 0x01;
    instruction->raw.evex.L         = (data[3] >> 5) & 0x01;
    instruction->raw.evex.b         = (data[3] >> 4) & 0x01;
    instruction->raw.evex.V2        = (data[3] >> 3) & 0x01;

    if (!instruction->raw.evex.V2 &&
        (instruction->machine_mode != ZYDIS_MACHINE_MODE_LONG_64))
    {
        return ZYDIS_STATUS_MALFORMED_EVEX;
    }

    instruction->raw.evex.aaa       = (data[3] >> 0) & 0x07;

    if (instruction->raw.evex.z && !instruction->raw.evex.aaa)
    {
        return ZYDIS_STATUS_INVALID_MASK; // TODO: Dedicated status code
    }

    // Update internal fields
    context->vector_unified.W    = instruction->raw.evex.W;
    context->vector_unified.R    = 0x01 & ~instruction->raw.evex.R;
    context->vector_unified.X    = 0x01 & ~instruction->raw.evex.X;
    context->vector_unified.B    = 0x01 & ~instruction->raw.evex.B;
    context->vector_unified.LL   = (data[3] >> 5) & 0x03;
    context->vector_unified.R2   = 0x01 & ~instruction->raw.evex.R2;
    context->vector_unified.V2   = 0x01 & ~instruction->raw.evex.V2;
    context->vector_unified.vvvv = 0x0F & ~instruction->raw.evex.vvvv;
    context->vector_unified.mask = instruction->raw.evex.aaa;

    if (!instruction->raw.evex.V2 && (instruction->machine_mode != ZYDIS_MACHINE_MODE_LONG_64))
    {
        return ZYDIS_STATUS_MALFORMED_EVEX;
    }
    if (!instruction->raw.evex.b && (context->vector_unified.LL == 3))
    {
        // LL = 3 is only valid for instructions with embedded rounding control
        return ZYDIS_STATUS_MALFORMED_EVEX;
    }

    return ZYAN_STATUS_SUCCESS;
}
#endif

#ifndef ZYDIS_DISABLE_KNC
/**
 * Decodes the `MVEX`-prefix.
 *
 * @param   context     A pointer to the `ZydisDecoderContext` struct.
 * @param   instruction A pointer to the `ZydisDecodedInstruction` struct.
 * @param   data        The `MVEX` bytes.
 *
 * @return  A zyan status code.
 */
static ZyanStatus ZydisDecodeMVEX(ZydisDecoderContext* context,
    ZydisDecodedInstruction* instruction, const ZyanU8 data[4])
{
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(data[0] == 0x62);
    ZYAN_ASSERT(instruction->raw.mvex.offset == instruction->length - 4);

    if (instruction->machine_mode != ZYDIS_MACHINE_MODE_LONG_64)
    {
        // MVEX is only valid in 64-bit mode
        return ZYDIS_STATUS_DECODING_ERROR;
    }

    instruction->attributes |= ZYDIS_ATTRIB_HAS_MVEX;
    instruction->raw.mvex.R    = (data[1] >> 7) & 0x01;
    instruction->raw.mvex.X    = (data[1] >> 6) & 0x01;
    instruction->raw.mvex.B    = (data[1] >> 5) & 0x01;
    instruction->raw.mvex.R2   = (data[1] >> 4) & 0x01;
    instruction->raw.mvex.mmmm = (data[1] >> 0) & 0x0F;

    if (instruction->raw.mvex.mmmm > 0x03)
    {
        // Invalid according to the intel documentation
        return ZYDIS_STATUS_INVALID_MAP;
    }

    instruction->raw.mvex.W    = (data[2] >> 7) & 0x01;
    instruction->raw.mvex.vvvv = (data[2] >> 3) & 0x0F;

    ZYAN_ASSERT(((data[2] >> 2) & 0x01) == 0x00);

    instruction->raw.mvex.pp   = (data[2] >> 0) & 0x03;
    instruction->raw.mvex.E    = (data[3] >> 7) & 0x01;
    instruction->raw.mvex.SSS  = (data[3] >> 4) & 0x07;
    instruction->raw.mvex.V2   = (data[3] >> 3) & 0x01;
    instruction->raw.mvex.kkk  = (data[3] >> 0) & 0x07;

    // Update internal fields
    context->vector_unified.W    = instruction->raw.mvex.W;
    context->vector_unified.R    = 0x01 & ~instruction->raw.mvex.R;
    context->vector_unified.X    = 0x01 & ~instruction->raw.mvex.X;
    context->vector_unified.B    = 0x01 & ~instruction->raw.mvex.B;
    context->vector_unified.R2   = 0x01 & ~instruction->raw.mvex.R2;
    context->vector_unified.V2   = 0x01 & ~instruction->raw.mvex.V2;
    context->vector_unified.LL   = 2;
    context->vector_unified.vvvv = 0x0F & ~instruction->raw.mvex.vvvv;
    context->vector_unified.mask = instruction->raw.mvex.kkk;

    return ZYAN_STATUS_SUCCESS;
}
#endif

/**
 * Decodes the `ModRM`-byte.
 *
 * @param   instruction A pointer to the `ZydisDecodedInstruction` struct.
 * @param   data        The `ModRM` byte.
 */
static void ZydisDecodeModRM(ZydisDecodedInstruction* instruction, ZyanU8 data)
{
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(!(instruction->attributes & ZYDIS_ATTRIB_HAS_MODRM));
    ZYAN_ASSERT(instruction->raw.modrm.offset == instruction->length - 1);

    instruction->attributes   |= ZYDIS_ATTRIB_HAS_MODRM;
    instruction->raw.modrm.mod = (data >> 6) & 0x03;
    instruction->raw.modrm.reg = (data >> 3) & 0x07;
    instruction->raw.modrm.rm  = (data >> 0) & 0x07;
}

/**
 * Decodes the `SIB`-byte.
 *
 * @param   instruction A pointer to the `ZydisDecodedInstruction` struct
 * @param   data        The `SIB` byte.
 */
static void ZydisDecodeSIB(ZydisDecodedInstruction* instruction, ZyanU8 data)
{
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(instruction->attributes & ZYDIS_ATTRIB_HAS_MODRM);
    ZYAN_ASSERT(instruction->raw.modrm.rm == 4);
    ZYAN_ASSERT(!(instruction->attributes & ZYDIS_ATTRIB_HAS_SIB));
    ZYAN_ASSERT(instruction->raw.sib.offset == instruction->length - 1);

    instruction->attributes    |= ZYDIS_ATTRIB_HAS_SIB;
    instruction->raw.sib.scale = (data >> 6) & 0x03;
    instruction->raw.sib.index = (data >> 3) & 0x07;
    instruction->raw.sib.base  = (data >> 0) & 0x07;
}

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

/**
 * Reads a displacement value.
 *
 * @param   state       A pointer to the `ZydisDecoderState` struct.
 * @param   instruction A pointer to the `ZydisDecodedInstruction` struct.
 * @param   size        The physical size of the displacement value.
 *
 * @return  A zyan status code.
 */
static ZyanStatus ZydisReadDisplacement(ZydisDecoderState* state,
    ZydisDecodedInstruction* instruction, ZyanU8 size)
{
    ZYAN_ASSERT(state);
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(instruction->raw.disp.size == 0);

    instruction->raw.disp.size = size;
    instruction->raw.disp.offset = instruction->length;

    switch (size)
    {
    case 8:
    {
        ZyanU8 value;
        ZYAN_CHECK(ZydisInputNext(state, instruction, &value));
        instruction->raw.disp.value = *(ZyanI8*)&value;
        break;
    }
    case 16:
    {
        ZyanU16 value;
        ZYAN_CHECK(ZydisInputNextBytes(state, instruction, (ZyanU8*)&value, 2));
        instruction->raw.disp.value = *(ZyanI16*)&value;
        break;
    }
    case 32:
    {
        ZyanU32 value;
        ZYAN_CHECK(ZydisInputNextBytes(state, instruction, (ZyanU8*)&value, 4));
        instruction->raw.disp.value = *(ZyanI32*)&value;
        break;
    }
    case 64:
    {
        ZyanU64 value;
        ZYAN_CHECK(ZydisInputNextBytes(state, instruction, (ZyanU8*)&value, 8));
        instruction->raw.disp.value = *(ZyanI64*)&value;
        break;
    }
    default:
        ZYAN_UNREACHABLE;
    }

    // TODO: Fix endianess on big-endian systems

    return ZYAN_STATUS_SUCCESS;
}

/**
 * Reads an immediate value.
 *
 * @param   state       A pointer to the `ZydisDecoderState` struct.
 * @param   instruction A pointer to the `ZydisDecodedInstruction` struct.
 * @param   id          The immediate id (either `0` or `1`).
 * @param   size        The physical size of the immediate value.
 * @param   is_signed   Signals, if the immediate value is signed.
 * @param   is_relative Signals, if the immediate value is a relative offset.
 *
 * @return  A zyan status code.
 */
static ZyanStatus ZydisReadImmediate(ZydisDecoderState* state,
    ZydisDecodedInstruction* instruction, ZyanU8 id, ZyanU8 size, ZyanBool is_signed,
    ZyanBool is_relative)
{
    ZYAN_ASSERT(state);
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT((id == 0) || (id == 1));
    ZYAN_ASSERT(is_signed || !is_relative);
    ZYAN_ASSERT(instruction->raw.imm[id].size == 0);

    instruction->raw.imm[id].size = size;
    instruction->raw.imm[id].offset = instruction->length;
    instruction->raw.imm[id].is_signed = is_signed;
    instruction->raw.imm[id].is_relative = is_relative;
    switch (size)
    {
    case 8:
    {
        ZyanU8 value;
        ZYAN_CHECK(ZydisInputNext(state, instruction, &value));
        if (is_signed)
        {
            instruction->raw.imm[id].value.s = (ZyanI8)value;
        } else
        {
            instruction->raw.imm[id].value.u = value;
        }
        break;
    }
    case 16:
    {
        ZyanU16 value;
        ZYAN_CHECK(ZydisInputNextBytes(state, instruction, (ZyanU8*)&value, 2));
        if (is_signed)
        {
            instruction->raw.imm[id].value.s = (ZyanI16)value;
        } else
        {
            instruction->raw.imm[id].value.u = value;
        }
        break;
    }
    case 32:
    {
        ZyanU32 value;
        ZYAN_CHECK(ZydisInputNextBytes(state, instruction, (ZyanU8*)&value, 4));
        if (is_signed)
        {
            instruction->raw.imm[id].value.s = (ZyanI32)value;
        } else
        {
            instruction->raw.imm[id].value.u = value;
        }
        break;
    }
    case 64:
    {
        ZyanU64 value;
        ZYAN_CHECK(ZydisInputNextBytes(state, instruction, (ZyanU8*)&value, 8));
        if (is_signed)
        {
            instruction->raw.imm[id].value.s = (ZyanI64)value;
        } else
        {
            instruction->raw.imm[id].value.u = value;
        }
        break;
    }
    default:
        ZYAN_UNREACHABLE;
    }

    // TODO: Fix endianess on big-endian systems

    return ZYAN_STATUS_SUCCESS;
}

/* ---------------------------------------------------------------------------------------------- */
/* Semantic instruction decoding                                                                  */
/* ---------------------------------------------------------------------------------------------- */

#ifndef ZYDIS_MINIMAL_MODE
/**
 * Calculates the register-id for a specific register-encoding and register-class.
 *
 * @param   context         A pointer to the `ZydisDecoderContext` struct.
 * @param   instruction     A pointer to the ` ZydisDecodedInstruction` struct.
 * @param   encoding        The register-encoding.
 * @param   register_class  The register-class.
 *
 * @return  A zyan status code.
 *
 * This function calculates the register-id by combining different fields and flags of previously
 * decoded structs.
 */
static ZyanU8 ZydisCalcRegisterId(const ZydisDecoderContext* context,
    const ZydisDecodedInstruction* instruction, ZydisRegisterEncoding encoding,
    ZydisRegisterClass register_class)
{
    ZYAN_ASSERT(context);
    ZYAN_ASSERT(instruction);

    // TODO: Combine OPCODE and IS4 in `ZydisPopulateRegisterIds` and get rid of this
    // TODO: function entirely

    switch (encoding)
    {
    case ZYDIS_REG_ENCODING_REG:
        return context->reg_info.id_reg;
    case ZYDIS_REG_ENCODING_NDSNDD:
        return context->reg_info.id_ndsndd;
    case ZYDIS_REG_ENCODING_RM:
        return context->reg_info.id_rm;
    case ZYDIS_REG_ENCODING_BASE:
        return context->reg_info.id_base;
    case ZYDIS_REG_ENCODING_INDEX:
    case ZYDIS_REG_ENCODING_VIDX:
        return context->reg_info.id_index;
    case ZYDIS_REG_ENCODING_OPCODE:
    {
        ZYAN_ASSERT((register_class == ZYDIS_REGCLASS_GPR8) ||
                    (register_class == ZYDIS_REGCLASS_GPR16) ||
                    (register_class == ZYDIS_REGCLASS_GPR32) ||
                    (register_class == ZYDIS_REGCLASS_GPR64));
        ZyanU8 value = (instruction->opcode & 0x0F);
        if (value > 7)
        {
            value = value - 8;
        }
        if (instruction->machine_mode != ZYDIS_MACHINE_MODE_LONG_64)
        {
            return value;
        }
        return value | (context->vector_unified.B << 3);
    }
    case ZYDIS_REG_ENCODING_IS4:
    {
        if (instruction->machine_mode != ZYDIS_MACHINE_MODE_LONG_64)
        {
            return (instruction->raw.imm[0].value.u >> 4) & 0x07;
        }
        ZyanU8 value = (instruction->raw.imm[0].value.u >> 4) & 0x0F;
        // We have to check the instruction-encoding, because the extension by bit [3] is only
        // valid for EVEX and MVEX instructions
        if ((instruction->encoding == ZYDIS_INSTRUCTION_ENCODING_EVEX) ||
            (instruction->encoding == ZYDIS_INSTRUCTION_ENCODING_MVEX))
        {
            switch (register_class)
            {
            case ZYDIS_REGCLASS_XMM:
            case ZYDIS_REGCLASS_YMM:
            case ZYDIS_REGCLASS_ZMM:
                value |= ((instruction->raw.imm[0].value.u & 0x08) << 1);
            default:
                break;
            }
        }
        return value;
    }
    case ZYDIS_REG_ENCODING_MASK:
        return context->vector_unified.mask;
    default:
        ZYAN_UNREACHABLE;
    }
}
#endif

#ifndef ZYDIS_MINIMAL_MODE
/**
 * Sets the operand-size and element-specific information for the given operand.
 *
 * @param   context         A pointer to the `ZydisDecoderContext` struct.
 * @param   instruction     A pointer to the `ZydisDecodedInstruction` struct.
 * @param   operand         A pointer to the `ZydisDecodedOperand` struct.
 * @param   definition      A pointer to the `ZydisOperandDefinition` struct.
 */
static void ZydisSetOperandSizeAndElementInfo(const ZydisDecoderContext* context,
    const ZydisDecodedInstruction* instruction, ZydisDecodedOperand* operand,
    const ZydisOperandDefinition* definition)
{
    ZYAN_ASSERT(context);
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(operand);
    ZYAN_ASSERT(definition);

    // Operand size
    switch (operand->type)
    {
    case ZYDIS_OPERAND_TYPE_REGISTER:
    {
        if (definition->size[context->eosz_index])
        {
            operand->size = definition->size[context->eosz_index] * 8;
        } else
        {
            operand->size = ZydisRegisterGetWidth(instruction->machine_mode,
                operand->reg.value);
        }
        operand->element_type = ZYDIS_ELEMENT_TYPE_INT;
        operand->element_size = operand->size;
        break;
    }
    case ZYDIS_OPERAND_TYPE_MEMORY:
        switch (instruction->encoding)
        {
        case ZYDIS_INSTRUCTION_ENCODING_LEGACY:
        case ZYDIS_INSTRUCTION_ENCODING_3DNOW:
        case ZYDIS_INSTRUCTION_ENCODING_XOP:
        case ZYDIS_INSTRUCTION_ENCODING_VEX:
            if (operand->mem.type == ZYDIS_MEMOP_TYPE_AGEN)
            {
                ZYAN_ASSERT(definition->size[context->eosz_index] == 0);
                operand->size = instruction->address_width;
                operand->element_type = ZYDIS_ELEMENT_TYPE_INT;
            } else
            {
                ZYAN_ASSERT(definition->size[context->eosz_index] ||
                    (instruction->meta.category == ZYDIS_CATEGORY_AMX_TILE));
                operand->size = definition->size[context->eosz_index] * 8;
            }
            break;
        case ZYDIS_INSTRUCTION_ENCODING_EVEX:
#ifndef ZYDIS_DISABLE_AVX512
            if (definition->size[context->eosz_index])
            {
                // Operand size is hardcoded
                operand->size = definition->size[context->eosz_index] * 8;
            } else
            {
                // Operand size depends on the tuple-type, the element-size and the number of
                // elements
                ZYAN_ASSERT(instruction->avx.vector_length);
                ZYAN_ASSERT(context->evex.element_size);
                switch (context->evex.tuple_type)
                {
                case ZYDIS_TUPLETYPE_FV:
                    if (instruction->avx.broadcast.mode)
                    {
                        operand->size = context->evex.element_size;
                    } else
                    {
                        operand->size = instruction->avx.vector_length;
                    }
                    break;
                case ZYDIS_TUPLETYPE_HV:
                    if (instruction->avx.broadcast.mode)
                    {
                        operand->size = context->evex.element_size;
                    } else
                    {
                        operand->size = (ZyanU16)instruction->avx.vector_length / 2;
                    }
                    break;
                case ZYDIS_TUPLETYPE_QUARTER:
                    if (instruction->avx.broadcast.mode)
                    {
                        operand->size = context->evex.element_size;
                    }
                    else
                    {
                        operand->size = (ZyanU16)instruction->avx.vector_length / 4;
                    }
                    break;
                default:
                    ZYAN_UNREACHABLE;
                }
            }
            ZYAN_ASSERT(operand->size);
#else
            ZYAN_UNREACHABLE;
#endif
            break;
        case ZYDIS_INSTRUCTION_ENCODING_MVEX:
#ifndef ZYDIS_DISABLE_KNC
            if (definition->size[context->eosz_index])
            {
                // Operand size is hardcoded
                operand->size = definition->size[context->eosz_index] * 8;
            } else
            {
                ZYAN_ASSERT(definition->element_type == ZYDIS_IELEMENT_TYPE_VARIABLE);
                ZYAN_ASSERT(instruction->avx.vector_length == 512);

                switch (instruction->avx.conversion.mode)
                {
                case ZYDIS_CONVERSION_MODE_INVALID:
                    operand->size = 512;
                    switch (context->mvex.functionality)
                    {
                    case ZYDIS_MVEX_FUNC_SF_32:
                    case ZYDIS_MVEX_FUNC_SF_32_BCST_4TO16:
                    case ZYDIS_MVEX_FUNC_UF_32:
                    case ZYDIS_MVEX_FUNC_DF_32:
                        operand->element_type = ZYDIS_ELEMENT_TYPE_FLOAT32;
                        operand->element_size = 32;
                        break;
                    case ZYDIS_MVEX_FUNC_SF_32_BCST:
                        operand->size = 256;
                        operand->element_type = ZYDIS_ELEMENT_TYPE_FLOAT32;
                        operand->element_size = 32;
                        break;
                    case ZYDIS_MVEX_FUNC_SI_32:
                    case ZYDIS_MVEX_FUNC_SI_32_BCST_4TO16:
                    case ZYDIS_MVEX_FUNC_UI_32:
                    case ZYDIS_MVEX_FUNC_DI_32:
                        operand->element_type = ZYDIS_ELEMENT_TYPE_INT;
                        operand->element_size = 32;
                        break;
                    case ZYDIS_MVEX_FUNC_SI_32_BCST:
                        operand->size = 256;
                        operand->element_type = ZYDIS_ELEMENT_TYPE_INT;
                        operand->element_size = 32;
                        break;
                    case ZYDIS_MVEX_FUNC_SF_64:
                    case ZYDIS_MVEX_FUNC_UF_64:
                    case ZYDIS_MVEX_FUNC_DF_64:
                        operand->element_type = ZYDIS_ELEMENT_TYPE_FLOAT64;
                        operand->element_size = 64;
                        break;
                    case ZYDIS_MVEX_FUNC_SI_64:
                    case ZYDIS_MVEX_FUNC_UI_64:
                    case ZYDIS_MVEX_FUNC_DI_64:
                        operand->element_type = ZYDIS_ELEMENT_TYPE_INT;
                        operand->element_size = 64;
                        break;
                    default:
                        ZYAN_UNREACHABLE;
                    }
                    break;
                case ZYDIS_CONVERSION_MODE_FLOAT16:
                    operand->size = 256;
                    operand->element_type = ZYDIS_ELEMENT_TYPE_FLOAT16;
                    operand->element_size = 16;
                    break;
                case ZYDIS_CONVERSION_MODE_SINT16:
                    operand->size = 256;
                    operand->element_type = ZYDIS_ELEMENT_TYPE_INT;
                    operand->element_size = 16;
                    break;
                case ZYDIS_CONVERSION_MODE_UINT16:
                    operand->size = 256;
                    operand->element_type = ZYDIS_ELEMENT_TYPE_UINT;
                    operand->element_size = 16;
                    break;
                case ZYDIS_CONVERSION_MODE_SINT8:
                    operand->size = 128;
                    operand->element_type = ZYDIS_ELEMENT_TYPE_INT;
                    operand->element_size = 8;
                    break;
                case ZYDIS_CONVERSION_MODE_UINT8:
                    operand->size = 128;
                    operand->element_type = ZYDIS_ELEMENT_TYPE_UINT;
                    operand->element_size = 8;
                    break;
                default:
                    ZYAN_UNREACHABLE;
                }

                switch (instruction->avx.broadcast.mode)
                {
                case ZYDIS_BROADCAST_MODE_INVALID:
                    // Nothing to do here
                    break;
                case ZYDIS_BROADCAST_MODE_1_TO_8:
                case ZYDIS_BROADCAST_MODE_1_TO_16:
                    operand->size = operand->element_size;
                    break;
                case ZYDIS_BROADCAST_MODE_4_TO_8:
                case ZYDIS_BROADCAST_MODE_4_TO_16:
                    operand->size = operand->element_size * 4;
                    break;
                default:
                    ZYAN_UNREACHABLE;
                }
            }
#else
            ZYAN_UNREACHABLE;
#endif
            break;
        default:
            ZYAN_UNREACHABLE;
        }
        break;
    case ZYDIS_OPERAND_TYPE_POINTER:
        ZYAN_ASSERT((instruction->raw.imm[0].size == 16) ||
                    (instruction->raw.imm[0].size == 32));
        ZYAN_ASSERT( instruction->raw.imm[1].size == 16);
        operand->size = instruction->raw.imm[0].size + instruction->raw.imm[1].size;
        break;
    case ZYDIS_OPERAND_TYPE_IMMEDIATE:
        operand->size = definition->size[context->eosz_index] * 8;
        break;
    default:
        ZYAN_UNREACHABLE;
    }

    // Element-type and -size
    if (definition->element_type && (definition->element_type != ZYDIS_IELEMENT_TYPE_VARIABLE))
    {
        ZydisGetElementInfo(definition->element_type, &operand->element_type,
            &operand->element_size);
        if (!operand->element_size)
        {
            // The element size is the same as the operand size. This is used for single element
            // scaling operands
            operand->element_size = operand->size;
        }
    }

    // Element count
    if (operand->element_size && operand->size && (operand->element_type != ZYDIS_ELEMENT_TYPE_CC))
    {
        operand->element_count = operand->size / operand->element_size;
    } else
    {
        operand->element_count = 1;
    }
}
#endif

#ifndef ZYDIS_MINIMAL_MODE
/**
 * Decodes an register-operand.
 *
 * @param   instruction      A pointer to the `ZydisDecodedInstruction` struct.
 * @param   operand          A pointer to the `ZydisDecodedOperand` struct.
 * @param   register_class   The register class.
 * @param   register_id      The register id.
 *
 * @return  A zyan status code.
 */
static ZyanStatus ZydisDecodeOperandRegister(const ZydisDecodedInstruction* instruction,
    ZydisDecodedOperand* operand, ZydisRegisterClass register_class, ZyanU8 register_id)
{
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(operand);

    operand->type = ZYDIS_OPERAND_TYPE_REGISTER;

    if (register_class == ZYDIS_REGCLASS_GPR8)
    {
        if ((instruction->attributes & ZYDIS_ATTRIB_HAS_REX) && (register_id >= 4))
        {
            operand->reg.value = ZYDIS_REGISTER_SPL + (register_id - 4);
        } else
        {
            operand->reg.value = ZYDIS_REGISTER_AL + register_id;
        }
    } else
    {
        operand->reg.value = ZydisRegisterEncode(register_class, register_id);
        ZYAN_ASSERT(operand->reg.value);
        /*if (!operand->reg.value)
        {
            return ZYAN_STATUS_BAD_REGISTER;
        }*/
    }

    return ZYAN_STATUS_SUCCESS;
}
#endif

#ifndef ZYDIS_MINIMAL_MODE
/**
 * Decodes a memory operand.
 *
 * @param   context             A pointer to the `ZydisDecoderContext` struct.
 * @param   instruction         A pointer to the `ZydisDecodedInstruction` struct.
 * @param   operand             A pointer to the `ZydisDecodedOperand` struct.
 * @param   vidx_register_class The register-class to use as the index register-class for
 *                              instructions with `VSIB` addressing.
 *
 * @return  A zyan status code.
 */
static ZyanStatus ZydisDecodeOperandMemory(const ZydisDecoderContext* context,
    const ZydisDecodedInstruction* instruction, ZydisDecodedOperand* operand,
    ZydisRegisterClass vidx_register_class)
{
    ZYAN_ASSERT(context);
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(operand);
    ZYAN_ASSERT(instruction->attributes & ZYDIS_ATTRIB_HAS_MODRM);
    ZYAN_ASSERT(instruction->raw.modrm.mod != 3);
    ZYAN_ASSERT(!vidx_register_class || ((instruction->raw.modrm.rm == 4) &&
        ((instruction->address_width == 32) || (instruction->address_width == 64))));

    operand->type = ZYDIS_OPERAND_TYPE_MEMORY;
    operand->mem.type = ZYDIS_MEMOP_TYPE_MEM;

    const ZyanU8 modrm_rm = instruction->raw.modrm.rm;
    ZyanU8 displacement_size = 0;
    switch (instruction->address_width)
    {
    case 16:
    {
        static const ZydisRegister bases[] =
        {
            ZYDIS_REGISTER_BX,   ZYDIS_REGISTER_BX,   ZYDIS_REGISTER_BP,   ZYDIS_REGISTER_BP,
            ZYDIS_REGISTER_SI,   ZYDIS_REGISTER_DI,   ZYDIS_REGISTER_BP,   ZYDIS_REGISTER_BX
        };
        static const ZydisRegister indices[] =
        {
            ZYDIS_REGISTER_SI,   ZYDIS_REGISTER_DI,   ZYDIS_REGISTER_SI,   ZYDIS_REGISTER_DI,
            ZYDIS_REGISTER_NONE, ZYDIS_REGISTER_NONE, ZYDIS_REGISTER_NONE, ZYDIS_REGISTER_NONE
        };
        operand->mem.base = bases[modrm_rm];
        operand->mem.index = indices[modrm_rm];
        operand->mem.scale = (operand->mem.index == ZYDIS_REGISTER_NONE) ? 0 : 1;
        switch (instruction->raw.modrm.mod)
        {
        case 0:
            if (modrm_rm == 6)
            {
                displacement_size = 16;
                operand->mem.base = ZYDIS_REGISTER_NONE;
            }
            break;
        case 1:
            displacement_size = 8;
            break;
        case 2:
            displacement_size = 16;
            break;
        default:
            ZYAN_UNREACHABLE;
        }
        break;
    }
    case 32:
    {
        operand->mem.base = ZYDIS_REGISTER_EAX + ZydisCalcRegisterId(context, instruction,
            ZYDIS_REG_ENCODING_BASE, ZYDIS_REGCLASS_GPR32);
        switch (instruction->raw.modrm.mod)
        {
        case 0:
            if (modrm_rm == 5)
            {
                if (instruction->machine_mode == ZYDIS_MACHINE_MODE_LONG_64)
                {
                    operand->mem.base = ZYDIS_REGISTER_EIP;
                } else
                {
                    operand->mem.base = ZYDIS_REGISTER_NONE;
                }
                displacement_size = 32;
            }
            break;
        case 1:
            displacement_size = 8;
            break;
        case 2:
            displacement_size = 32;
            break;
        default:
            ZYAN_UNREACHABLE;
        }
        if (modrm_rm == 4)
        {
            ZYAN_ASSERT(instruction->attributes & ZYDIS_ATTRIB_HAS_SIB);
            operand->mem.index =
                ZydisRegisterEncode(vidx_register_class ? vidx_register_class : ZYDIS_REGCLASS_GPR32,
                    ZydisCalcRegisterId(context, instruction,
                        vidx_register_class ? ZYDIS_REG_ENCODING_VIDX : ZYDIS_REG_ENCODING_INDEX,
                        vidx_register_class ? vidx_register_class : ZYDIS_REGCLASS_GPR32));
            operand->mem.scale = (1 << instruction->raw.sib.scale);
            if (operand->mem.index == ZYDIS_REGISTER_ESP)
            {
                operand->mem.index = ZYDIS_REGISTER_NONE;
                operand->mem.scale = 0;
            }
            if (operand->mem.base == ZYDIS_REGISTER_EBP)
            {
                if (instruction->raw.modrm.mod == 0)
                {
                    operand->mem.base = ZYDIS_REGISTER_NONE;
                }
                displacement_size = (instruction->raw.modrm.mod == 1) ? 8 : 32;
            }
        } else
        {
            operand->mem.index = ZYDIS_REGISTER_NONE;
            operand->mem.scale = 0;
        }
        break;
    }
    case 64:
    {
        operand->mem.base = ZYDIS_REGISTER_RAX + ZydisCalcRegisterId(context, instruction,
            ZYDIS_REG_ENCODING_BASE, ZYDIS_REGCLASS_GPR64);
        switch (instruction->raw.modrm.mod)
        {
        case 0:
            if (modrm_rm == 5)
            {
                if (instruction->machine_mode == ZYDIS_MACHINE_MODE_LONG_64)
                {
                    operand->mem.base = ZYDIS_REGISTER_RIP;
                } else
                {
                    operand->mem.base = ZYDIS_REGISTER_NONE;
                }
                displacement_size = 32;
            }
            break;
        case 1:
            displacement_size = 8;
            break;
        case 2:
            displacement_size = 32;
            break;
        default:
            ZYAN_UNREACHABLE;
        }
        if ((modrm_rm & 0x07) == 4)
        {
            ZYAN_ASSERT(instruction->attributes & ZYDIS_ATTRIB_HAS_SIB);
            operand->mem.index =
                ZydisRegisterEncode(vidx_register_class ? vidx_register_class : ZYDIS_REGCLASS_GPR64,
                    ZydisCalcRegisterId(context, instruction,
                        vidx_register_class ? ZYDIS_REG_ENCODING_VIDX : ZYDIS_REG_ENCODING_INDEX,
                        vidx_register_class ? vidx_register_class : ZYDIS_REGCLASS_GPR64));
            operand->mem.scale = (1 << instruction->raw.sib.scale);
            if (operand->mem.index == ZYDIS_REGISTER_RSP)
            {
                operand->mem.index = ZYDIS_REGISTER_NONE;
                operand->mem.scale = 0;
            }
            if ((operand->mem.base == ZYDIS_REGISTER_RBP) ||
                (operand->mem.base == ZYDIS_REGISTER_R13))
            {
                if (instruction->raw.modrm.mod == 0)
                {
                    operand->mem.base = ZYDIS_REGISTER_NONE;
                }
                displacement_size = (instruction->raw.modrm.mod == 1) ? 8 : 32;
            }
        } else
        {
            operand->mem.index = ZYDIS_REGISTER_NONE;
            operand->mem.scale = 0;
        }
        break;
    }
    default:
        ZYAN_UNREACHABLE;
    }
    if (displacement_size)
    {
        ZYAN_ASSERT(instruction->raw.disp.size == displacement_size);
        operand->mem.disp.has_displacement = ZYAN_TRUE;
        operand->mem.disp.value = instruction->raw.disp.value;
    }
    return ZYAN_STATUS_SUCCESS;
}
#endif

#ifndef ZYDIS_MINIMAL_MODE
/**
 * Decodes an implicit register operand.
 *
 * @param   decoder         A pointer to the `ZydisDecoder` instance.
 * @param   context         A pointer to the `ZydisDecoderContext` struct.
 * @param   instruction     A pointer to the `ZydisDecodedInstruction` struct.
 * @param   operand         A pointer to the `ZydisDecodedOperand` struct.
 * @param   definition      A pointer to the `ZydisOperandDefinition` struct.
 */
static void ZydisDecodeOperandImplicitRegister(const ZydisDecoder* decoder,
    const ZydisDecoderContext* context, const ZydisDecodedInstruction* instruction,
    ZydisDecodedOperand* operand, const ZydisOperandDefinition* definition)
{
    ZYAN_ASSERT(context);
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(operand);
    ZYAN_ASSERT(definition);

    operand->type = ZYDIS_OPERAND_TYPE_REGISTER;

    switch (definition->op.reg.type)
    {
    case ZYDIS_IMPLREG_TYPE_STATIC:
        operand->reg.value = definition->op.reg.reg.reg;
        break;
    case ZYDIS_IMPLREG_TYPE_GPR_OSZ:
    {
        static const ZydisRegisterClass lookup[3] =
        {
            ZYDIS_REGCLASS_GPR16,
            ZYDIS_REGCLASS_GPR32,
            ZYDIS_REGCLASS_GPR64
        };
        operand->reg.value =
            ZydisRegisterEncode(lookup[context->eosz_index], definition->op.reg.reg.id);
        break;
    }
    case ZYDIS_IMPLREG_TYPE_GPR_ASZ:
        operand->reg.value = ZydisRegisterEncode(
            (instruction->address_width    == 16) ? ZYDIS_REGCLASS_GPR16  :
            (instruction->address_width    == 32) ? ZYDIS_REGCLASS_GPR32  : ZYDIS_REGCLASS_GPR64,
            definition->op.reg.reg.id);
        break;
    case ZYDIS_IMPLREG_TYPE_IP_ASZ:
        operand->reg.value =
            (instruction->address_width    == 16) ? ZYDIS_REGISTER_IP     :
            (instruction->address_width    == 32) ? ZYDIS_REGISTER_EIP    : ZYDIS_REGISTER_RIP;
        break;
    case ZYDIS_IMPLREG_TYPE_GPR_SSZ:
        operand->reg.value = ZydisRegisterEncode(
            (decoder->stack_width == ZYDIS_STACK_WIDTH_16) ? ZYDIS_REGCLASS_GPR16 :
            (decoder->stack_width == ZYDIS_STACK_WIDTH_32) ? ZYDIS_REGCLASS_GPR32 :
                                                             ZYDIS_REGCLASS_GPR64,
            definition->op.reg.reg.id);
        break;
    case ZYDIS_IMPLREG_TYPE_IP_SSZ:
        operand->reg.value =
            (decoder->stack_width == ZYDIS_STACK_WIDTH_16) ? ZYDIS_REGISTER_EIP    :
            (decoder->stack_width == ZYDIS_STACK_WIDTH_32) ? ZYDIS_REGISTER_EIP    :
                                                             ZYDIS_REGISTER_RIP;
        break;
    case ZYDIS_IMPLREG_TYPE_FLAGS_SSZ:
        operand->reg.value =
            (decoder->stack_width == ZYDIS_STACK_WIDTH_16) ? ZYDIS_REGISTER_FLAGS  :
            (decoder->stack_width == ZYDIS_STACK_WIDTH_32) ? ZYDIS_REGISTER_EFLAGS :
                                                             ZYDIS_REGISTER_RFLAGS;
        break;
    default:
        ZYAN_UNREACHABLE;
    }
}
#endif

#ifndef ZYDIS_MINIMAL_MODE
/**
 * Decodes an implicit memory operand.
 *
 * @param   decoder         A pointer to the `ZydisDecoder` instance.
 * @param   context         A pointer to the `ZydisDecoderContext` struct.
 * @param   instruction     A pointer to the `ZydisDecodedInstruction` struct.
 * @param   operand         A pointer to the `ZydisDecodedOperand` struct.
 * @param   definition      A pointer to the `ZydisOperandDefinition` struct.
 */
static void ZydisDecodeOperandImplicitMemory(const ZydisDecoder* decoder,
    const ZydisDecoderContext* context, const ZydisDecodedInstruction* instruction,
    ZydisDecodedOperand* operand, const ZydisOperandDefinition* definition)
{
    ZYAN_ASSERT(context);
    ZYAN_ASSERT(operand);
    ZYAN_ASSERT(definition);

    static const ZydisRegisterClass lookup[3] =
    {
        ZYDIS_REGCLASS_GPR16,
        ZYDIS_REGCLASS_GPR32,
        ZYDIS_REGCLASS_GPR64
    };

    operand->type = ZYDIS_OPERAND_TYPE_MEMORY;
    operand->mem.type = ZYDIS_MEMOP_TYPE_MEM;

    switch (definition->op.mem.base)
    {
    case ZYDIS_IMPLMEM_BASE_AGPR_REG:
        operand->mem.base = ZydisRegisterEncode(lookup[context->easz_index],
            ZydisCalcRegisterId(context, instruction, ZYDIS_REG_ENCODING_REG,
                lookup[context->easz_index]));
        break;
    case ZYDIS_IMPLMEM_BASE_AGPR_RM:
        operand->mem.base = ZydisRegisterEncode(lookup[context->easz_index],
            ZydisCalcRegisterId(context, instruction, ZYDIS_REG_ENCODING_RM,
                lookup[context->easz_index]));
        break;
    case ZYDIS_IMPLMEM_BASE_AAX:
        operand->mem.base = ZydisRegisterEncode(lookup[context->easz_index], 0);
        break;
    case ZYDIS_IMPLMEM_BASE_ADX:
        operand->mem.base = ZydisRegisterEncode(lookup[context->easz_index], 2);
        break;
    case ZYDIS_IMPLMEM_BASE_ABX:
        operand->mem.base = ZydisRegisterEncode(lookup[context->easz_index], 3);
        break;
    case ZYDIS_IMPLMEM_BASE_ASI:
        operand->mem.base = ZydisRegisterEncode(lookup[context->easz_index], 6);
        break;
    case ZYDIS_IMPLMEM_BASE_ADI:
        operand->mem.base = ZydisRegisterEncode(lookup[context->easz_index], 7);
        break;
    case ZYDIS_IMPLMEM_BASE_SSP:
        operand->mem.base = ZydisRegisterEncode(lookup[decoder->stack_width], 4);
        break;
    case ZYDIS_IMPLMEM_BASE_SBP:
        operand->mem.base = ZydisRegisterEncode(lookup[decoder->stack_width], 5);
        break;
    default:
        ZYAN_UNREACHABLE;
    }

    if (definition->op.mem.seg)
    {
        operand->mem.segment =
            ZydisRegisterEncode(ZYDIS_REGCLASS_SEGMENT, definition->op.mem.seg - 1);
        ZYAN_ASSERT(operand->mem.segment);
    }
}
#endif

#ifndef ZYDIS_MINIMAL_MODE
static ZyanStatus ZydisDecodeOperands(const ZydisDecoder* decoder, const ZydisDecoderContext* context,
    const ZydisDecodedInstruction* instruction, ZydisDecodedOperand* operands, ZyanU8 operand_count)
{
    ZYAN_ASSERT(decoder);
    ZYAN_ASSERT(context);
    ZYAN_ASSERT(context->definition);
    ZYAN_ASSERT(instruction);
    ZYAN_ASSERT(operands);
    ZYAN_ASSERT(operand_count);
    ZYAN_ASSERT(operand_count <= instruction->operand_count);

    const ZydisInstructionDefinition* definition = context->definition;
    const ZydisOperandDefinition* operand = ZydisGetOperandDefinitions(definition);

    ZYAN_MEMSET(operands, 0, sizeof(ZydisDecodedOperand) * operand_count);

    ZyanU8 imm_id = 0;
    for (ZyanU8 i = 0; i < operand_count; ++i)
    {
        ZydisRegisterClass register_class = ZYDIS_REGCLASS_INVALID;

        operands[i].id = i;
        operands[i].visibility = operand->visibility;
        operands[i].actions = operand->actions;
        ZYAN_ASSERT(!(operand->actions &
            ZYDIS_OPERAND_ACTION_READ & ZYDIS_OPERAND_ACTION_CONDREAD) ||
            (operand->actions & ZYDIS_OPERAND_ACTION_READ) ^
            (operand->actions & ZYDIS_OPERAND_ACTION_CONDREAD));
        ZYAN_ASSERT(!(operand->actions &
            ZYDIS_OPERAND_ACTION_WRITE & ZYDIS_OPERAND_ACTION_CONDWRITE) ||
            (operand->actions & ZYDIS_OPERAND_ACTION_WRITE) ^
            (operand->actions & ZYDIS_OPERAND_ACTION_CONDWRITE));

        // Implicit operands
        switch (operand->type)
        {
        case ZYDIS_SEMANTIC_OPTYPE_IMPLICIT_REG:
            ZydisDecodeOperandImplicitRegister(decoder, context, instruction, &operands[i], operand);
            break;
        case ZYDIS_SEMANTIC_OPTYPE_IMPLICIT_MEM:
            ZydisDecodeOperandImplicitMemory(decoder, context, instruction, &operands[i], operand);
            break;
        case ZYDIS_SEMANTIC_OPTYPE_IMPLICIT_IMM1:
            operands[i].type = ZYDIS_OPERAND_TYPE_IMMEDIATE;
            operands[i].size = 8;
            operands[i].imm.value.u = 1;
            operands[i].imm.is_signed = ZYAN_FALSE;
            operands[i].imm.is_relative = ZYAN_FALSE;
            break;
        default:
            break;
        }
        if (operands[i].type)
        {
            goto FinalizeOperand;
        }

        operands[i].encoding = operand->op.encoding;

        // Register operands
        switch (operand->type)
        {
        case ZYDIS_SEMANTIC_OPTYPE_GPR8:
            register_class = ZYDIS_REGCLASS_GPR8;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_GPR16:
            register_class = ZYDIS_REGCLASS_GPR16;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_GPR32:
            register_class = ZYDIS_REGCLASS_GPR32;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_GPR64:
            register_class = ZYDIS_REGCLASS_GPR64;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_GPR16_32_64:
            ZYAN_ASSERT((instruction->operand_width == 16) || (instruction->operand_width == 32) ||
                (instruction->operand_width == 64));
            register_class =
                (instruction->operand_width == 16) ? ZYDIS_REGCLASS_GPR16 : (
                    (instruction->operand_width == 32) ? ZYDIS_REGCLASS_GPR32 : ZYDIS_REGCLASS_GPR64);
            break;
        case ZYDIS_SEMANTIC_OPTYPE_GPR32_32_64:
            ZYAN_ASSERT((instruction->operand_width == 16) || (instruction->operand_width == 32) ||
                (instruction->operand_width == 64));
            register_class =
                (instruction->operand_width == 16) ? ZYDIS_REGCLASS_GPR32 : (
                    (instruction->operand_width == 32) ? ZYDIS_REGCLASS_GPR32 : ZYDIS_REGCLASS_GPR64);
            break;
        case ZYDIS_SEMANTIC_OPTYPE_GPR16_32_32:
            ZYAN_ASSERT((instruction->operand_width == 16) || (instruction->operand_width == 32) ||
                (instruction->operand_width == 64));
            register_class =
                (instruction->operand_width == 16) ? ZYDIS_REGCLASS_GPR16 : ZYDIS_REGCLASS_GPR32;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_GPR_ASZ:
            ZYAN_ASSERT((instruction->address_width == 16) || (instruction->address_width == 32) ||
                (instruction->address_width == 64));
            register_class =
                (instruction->address_width == 16) ? ZYDIS_REGCLASS_GPR16 : (
                    (instruction->address_width == 32) ? ZYDIS_REGCLASS_GPR32 : ZYDIS_REGCLASS_GPR64);
            break;
        case ZYDIS_SEMANTIC_OPTYPE_FPR:
            register_class = ZYDIS_REGCLASS_X87;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_MMX:
            register_class = ZYDIS_REGCLASS_MMX;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_XMM:
            register_class = ZYDIS_REGCLASS_XMM;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_YMM:
            register_class = ZYDIS_REGCLASS_YMM;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_ZMM:
            register_class = ZYDIS_REGCLASS_ZMM;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_TMM:
            register_class = ZYDIS_REGCLASS_TMM;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_BND:
            register_class = ZYDIS_REGCLASS_BOUND;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_SREG:
            register_class = ZYDIS_REGCLASS_SEGMENT;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_CR:
            register_class = ZYDIS_REGCLASS_CONTROL;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_DR:
            register_class = ZYDIS_REGCLASS_DEBUG;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_MASK:
            register_class = ZYDIS_REGCLASS_MASK;
            break;
        default:
            break;
        }
        if (register_class)
        {
            switch (operand->op.encoding)
            {
            case ZYDIS_OPERAND_ENCODING_MODRM_REG:
                ZYAN_CHECK(
                    ZydisDecodeOperandRegister(
                        instruction, &operands[i], register_class,
                        ZydisCalcRegisterId(
                            context, instruction, ZYDIS_REG_ENCODING_REG, register_class)));
                break;
            case ZYDIS_OPERAND_ENCODING_MODRM_RM:
                ZYAN_CHECK(
                    ZydisDecodeOperandRegister(
                        instruction, &operands[i], register_class,
                        ZydisCalcRegisterId(
                            context, instruction, ZYDIS_REG_ENCODING_RM, register_class)));
                break;
            case ZYDIS_OPERAND_ENCODING_OPCODE:
                ZYAN_CHECK(
                    ZydisDecodeOperandRegister(
                        instruction, &operands[i], register_class,
                        ZydisCalcRegisterId(
                            context, instruction, ZYDIS_REG_ENCODING_OPCODE, register_class)));
                break;
            case ZYDIS_OPERAND_ENCODING_NDSNDD:
                ZYAN_CHECK(
                    ZydisDecodeOperandRegister(
                        instruction, &operands[i], register_class,
                        ZydisCalcRegisterId(
                            context, instruction, ZYDIS_REG_ENCODING_NDSNDD, register_class)));
                break;
            case ZYDIS_OPERAND_ENCODING_MASK:
                ZYAN_CHECK(
                    ZydisDecodeOperandRegister(
                        instruction, &operands[i], register_class,
                        ZydisCalcRegisterId(
                            context, instruction, ZYDIS_REG_ENCODING_MASK, register_class)));
                break;
            case ZYDIS_OPERAND_ENCODING_IS4:
                ZYAN_CHECK(
                    ZydisDecodeOperandRegister(
                        instruction, &operands[i], register_class,
                        ZydisCalcRegisterId(
                            context, instruction, ZYDIS_REG_ENCODING_IS4, register_class)));
                break;
            default:
                ZYAN_UNREACHABLE;
            }

            if (operand->is_multisource4)
            {
                operands[i].attributes |= ZYDIS_OATTRIB_IS_MULTISOURCE4;
            }

            goto FinalizeOperand;
        }

        // Memory operands
        switch (operand->type)
        {
        case ZYDIS_SEMANTIC_OPTYPE_MEM:
            ZYAN_CHECK(
                ZydisDecodeOperandMemory(
                    context, instruction, &operands[i], ZYDIS_REGCLASS_INVALID));
            break;
        case ZYDIS_SEMANTIC_OPTYPE_MEM_VSIBX:
            ZYAN_CHECK(
                ZydisDecodeOperandMemory(
                    context, instruction, &operands[i], ZYDIS_REGCLASS_XMM));
            operands[i].mem.type = ZYDIS_MEMOP_TYPE_VSIB;
            break;
        case ZYDIS_SEMANTIC_OPTYPE_MEM_VSIBY:
            ZYAN_CHECK(
                ZydisDecodeOperandMemory(
--> --------------------

--> maximum size reached

--> --------------------