tor-browser

EncoderData.h (8293B)

---

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

 Zyan Disassembler Library (Zydis)

 Original Author : Mappa

* 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.

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

#ifndef ZYDIS_INTERNAL_ENCODERDATA_H
#define ZYDIS_INTERNAL_ENCODERDATA_H

#include "zydis/Zycore/Defines.h"
#include "zydis/Zydis/Mnemonic.h"
#include "zydis/Zydis/SharedTypes.h"

/**
* Used in encoder's table to represent standard ISA sizes in form of bit flags.
*/
typedef enum ZydisWidthFlag_
{
   ZYDIS_WIDTH_INVALID = 0x00,
   ZYDIS_WIDTH_16      = 0x01,
   ZYDIS_WIDTH_32      = 0x02,
   ZYDIS_WIDTH_64      = 0x04,

   /**
    * Maximum value of this enum.
    */
   ZYDIS_WIDTH_MAX_VALUE = (ZYDIS_WIDTH_64 | (ZYDIS_WIDTH_64 - 1)),
   /**
    * The minimum number of bits required to represent all values of this enum.
    */
   ZYDIS_WIDTH_REQUIRED_BITS = ZYAN_BITS_TO_REPRESENT(ZYDIS_WIDTH_MAX_VALUE)
} ZydisWidthFlag;

/**
* Used in encoder's table to represent mandatory instruction prefix. Using this enum instead of
* actual prefix value saves space.
*/
typedef enum ZydisMandatoryPrefix_
{
   ZYDIS_MANDATORY_PREFIX_NONE,
   ZYDIS_MANDATORY_PREFIX_66,
   ZYDIS_MANDATORY_PREFIX_F2,
   ZYDIS_MANDATORY_PREFIX_F3,

   /**
    * Maximum value of this enum.
    */
   ZYDIS_MANDATORY_PREFIX_MAX_VALUE = ZYDIS_MANDATORY_PREFIX_F3,
   /**
    * The minimum number of bits required to represent all values of this enum.
    */
   ZYDIS_MANDATORY_PREFIX_REQUIRED_BITS = ZYAN_BITS_TO_REPRESENT(ZYDIS_MANDATORY_PREFIX_MAX_VALUE)
} ZydisMandatoryPrefix;

/**
* Used in encoder's table to represent vector size supported by instruction definition.
*/
typedef enum ZydisVectorLength_
{
   ZYDIS_VECTOR_LENGTH_INVALID,
   ZYDIS_VECTOR_LENGTH_128,
   ZYDIS_VECTOR_LENGTH_256,
   ZYDIS_VECTOR_LENGTH_512,

   /**
    * Maximum value of this enum.
    */
   ZYDIS_VECTOR_LENGTH_MAX_VALUE = ZYDIS_VECTOR_LENGTH_512,
   /**
    * The minimum number of bits required to represent all values of this enum.
    */
   ZYDIS_VECTOR_LENGTH_REQUIRED_BITS = ZYAN_BITS_TO_REPRESENT(ZYDIS_VECTOR_LENGTH_MAX_VALUE)
} ZydisVectorLength;

/**
* Used in encoder's table to represent hint type supported by instruction definition.
*/
typedef enum ZydisSizeHint_
{
   ZYDIS_SIZE_HINT_NONE,
   ZYDIS_SIZE_HINT_ASZ,
   ZYDIS_SIZE_HINT_OSZ,

   /**
    * Maximum value of this enum.
    */
   ZYDIS_SIZE_HINT_MAX_VALUE = ZYDIS_SIZE_HINT_OSZ,
   /**
    * The minimum number of bits required to represent all values of this enum.
    */
   ZYDIS_SIZE_HINT_REQUIRED_BITS = ZYAN_BITS_TO_REPRESENT(ZYDIS_SIZE_HINT_MAX_VALUE)
} ZydisSizeHint;

/**
* Used in encoder's primary lookup table which allows to access a set of instruction definitions
* for specified mnemonic in constant time.
*/
typedef struct ZydisEncoderLookupEntry_
{
   /**
    * Index to main array of `ZydisEncodableInstruction`.
    */
   ZyanU16 encoder_reference;
   /**
    * The number of entries.
    */
   ZyanU8 instruction_count;
} ZydisEncoderLookupEntry;

#pragma pack(push, 1)

/**
* This structure is encoder's internal representation of encodable instruction definition.
*/
typedef struct ZydisEncodableInstruction_
{
   /**
    * Index to one of decoder's instruction definition arrays.
    */
   ZyanU16 instruction_reference;
   /**
    * Compressed information about operand count and types. Operand count is stored in lowest bits.
    * Types of subsequent operands are stored in higher bits.
    */
   ZyanU16 operand_mask;
   /**
    * The instruction-opcode.
    */
   ZyanU8 opcode;
   /**
    * The mandatory ModR/M value.
    */
   ZyanU8 modrm;
   /**
    * The instruction-encoding.
    */
   ZyanU8 encoding                 ZYAN_BITFIELD(ZYDIS_INSTRUCTION_ENCODING_REQUIRED_BITS);
   /**
    * The opcode map.
    */
   ZyanU8 opcode_map               ZYAN_BITFIELD(ZYDIS_OPCODE_MAP_REQUIRED_BITS);
   /**
    * The combination of allowed processor modes.
    */
   ZyanU8 modes                    ZYAN_BITFIELD(ZYDIS_WIDTH_REQUIRED_BITS);
   /**
    * The combination of allowed address sizes.
    */
   ZyanU8 address_sizes            ZYAN_BITFIELD(ZYDIS_WIDTH_REQUIRED_BITS);
   /**
    * The combination of allowed operand sizes.
    */
   ZyanU8 operand_sizes            ZYAN_BITFIELD(ZYDIS_WIDTH_REQUIRED_BITS);
   /**
    * The mandatory prefix.
    */
   ZyanU8 mandatory_prefix         ZYAN_BITFIELD(ZYDIS_MANDATORY_PREFIX_REQUIRED_BITS);
   /**
    * True if `REX.W` is required for this definition.
    */
   ZyanU8 rex_w                    ZYAN_BITFIELD(1);
   /**
    * The vector length.
    */
   ZyanU8 vector_length            ZYAN_BITFIELD(ZYDIS_MANDATORY_PREFIX_REQUIRED_BITS);
   /**
    * The accepted sizing hint.
    */
   ZyanU8 accepts_hint             ZYAN_BITFIELD(ZYDIS_SIZE_HINT_REQUIRED_BITS);
   /**
    * Indicates that next instruction definition can be safely used instead of current one. This
    * is used with some `VEX` instructions to take advantage of 2-byte `VEX` prefix when possible.
    * 2-byte `VEX` allows to use high registers only when operand is encoded in `modrm_reg`
    * (high bit in `REX.R`). Encoder uses swappable definitions to take advantage of this
    * optimization opportunity.
    *
    * Second use of this field is to handle special case for `mov` instruction. This particular
    * conflict is described in detail inside `ZydisHandleSwappableDefinition`.
    */
   ZyanU8 swappable                ZYAN_BITFIELD(1);
} ZydisEncodableInstruction;

#pragma pack(pop)

/**
* Contains information used by instruction size prediction algorithm inside
* `ZydisEncoderEncodeInstructionAbsolute`.
*/
typedef struct ZydisEncoderRelInfo_
{
   /**
    * Sizes of instruction variants. First index is effective address size. Second index is
    * desired immediate size (8, 16 and 32 bits respectively).
    */
   ZyanU8 size[3][3];
   /**
    * See `ZydisSizeHint`.
    */
   ZyanU8 accepts_scaling_hints;
   /**
    * True if instruction accepts branch hint prefixes.
    */
   ZyanBool accepts_branch_hints;
   /**
    * True if instruction accepts bound (`BND`) prefix.
    */
   ZyanBool accepts_bound;
} ZydisEncoderRelInfo;

/**
* Fetches array of `ZydisEncodableInstruction` structures and its size for given instruction 
* mnemonic. 
*
* @param   mnemonic    Instruction mnemonic.
* @param   instruction This variable will receive a pointer to the array of 
*                      `ZydisEncodableInstruction` structures.
*
* @return  Entry count (0 if function failed).
*/
ZyanU8 ZydisGetEncodableInstructions(ZydisMnemonic mnemonic, 
   const ZydisEncodableInstruction **instruction);

/**
* Fetches `ZydisEncoderRelInfo` record for given instruction mnemonic.
*
* @param   mnemonic    Instruction mnemonic.
*
* @return  Pointer to `ZydisEncoderRelInfo` structure or `ZYAN_NULL` if instruction doesn't have
*          relative operands.
*/
const ZydisEncoderRelInfo *ZydisGetRelInfo(ZydisMnemonic mnemonic);

#endif /* ZYDIS_INTERNAL_ENCODERDATA_H */