mirror of https://github.com/x64dbg/zydis
Implemented basic prefix encoding
This commit is contained in:
Joel Höner
parent
3d2365b6ed
commit
0793090388
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@ -36,50 +36,21 @@
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extern "C" {
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#endif
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/* ============================================================================================== */
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/* Types */
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/* ============================================================================================== */
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/**
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* @brief Defines the @c ZydisInstructionEncoder struct.
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*
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* All fields in this struct are private and may change anytime.
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*/
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typedef struct ZydisInstructionEncoder_
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{
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/**
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* @brief The output buffer.
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*/
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struct
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{
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uint8_t* buffer;
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size_t bufferLen;
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} output;
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} ZydisInstructionEncoder;
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/* ============================================================================================== */
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/* Exported functions */
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/* ============================================================================================== */
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/**
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* @brief Initializes the given @c ZydisInstructionEncoder instance.
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* @param decoder A pointer to the @c ZydisInstructionEncoder instance.
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* @return A zydis status code.
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*/
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ZYDIS_EXPORT ZydisStatus ZydisEncoderInitInstructionEncoder(ZydisInstructionEncoder* encoder);
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/**
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* @brief Encodes the given instruction info to byte-code.
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*
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* @param encoder A pointer to the @c ZydisInstructionEncoder instance.
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* @param buffer A pointer to the output buffer.
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* @param bufferLen The length of the output buffer.
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* @param info A pointer to the @c ZydisInstructionInfo struct to be encoded.
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*
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* @return A zydis status code.
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*/
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ZYDIS_EXPORT ZydisStatus ZydisEncoderEncodeInstruction(ZydisInstructionEncoder* encoder,
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const void* buffer, size_t bufferLen, ZydisInstructionInfo* info);
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ZYDIS_EXPORT ZydisStatus ZydisEncoderEncodeInstruction(const void* buffer, size_t bufferLen,
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ZydisInstructionInfo* info);
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/* ============================================================================================== */
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215
src/Encoder.c
215
src/Encoder.c
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@ -27,24 +27,217 @@
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#include <Zydis/Encoder.h>
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/* ============================================================================================== */
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/* Implementation of public functions */
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/* Internal context */
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/* ============================================================================================== */
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ZydisStatus ZydisEncoderInitInstructionEncoder(ZydisInstructionEncoder* encoder)
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/**
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* @brief The encoder context struct.
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*/
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typedef struct ZydisInstructionEncoder_
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{
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// Nothing yet.
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(void)encoder;
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return ZYDIS_STATUS_SUCCESS;
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uint8_t* buffer;
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size_t bufferLen;
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size_t writeOffs;
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ZydisInstructionInfo* info;
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} ZydisInstructionEncoder;
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/* ============================================================================================== */
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/* Internal helpers */
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/* ============================================================================================== */
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static ZydisStatus ZydisEmitByte(ZydisInstructionEncoder* encoder, uint8_t byte)
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{
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if (encoder->writeOffs + 1 >= encoder->bufferLen)
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{
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return ZYDIS_STATUS_INSUFFICIENT_BUFFER_SIZE;
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}
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encoder->buffer[encoder->writeOffs++] = byte;
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return ZYDIS_STATUS_SUCCESS;
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}
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ZydisStatus ZydisEncoderEncodeInstruction(ZydisInstructionEncoder* encoder,
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void* buffer, size_t bufferLen, ZydisInstructionInfo* info)
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static ZydisStatus ZydisEncodeLegacyPrefixes(ZydisInstructionEncoder* encoder)
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{
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if (!encoder || !info) return ZYDIS_STATUS_INVALID_PARAMETER;
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if (!buffer || !bufferLen) return ZYDIS_STATUS_INSUFFICIENT_BUFFER_SIZE;
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ZYDIS_ASSERT(encoder);
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uint64_t attribs = encoder->info->attributes;
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encoder->output.buffer = (uint8_t*)buffer;
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encoder->output.bufferLen = bufferLen;
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if (attribs & ZYDIS_ATTRIB_HAS_LOCK)
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{
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ZYDIS_CHECK(ZydisEmitByte(encoder, 0xF0));
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}
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if (attribs & (ZYDIS_ATTRIB_HAS_REP | ZYDIS_ATTRIB_HAS_REPE | ZYDIS_ATTRIB_HAS_XRELEASE))
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{
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ZYDIS_CHECK(ZydisEmitByte(encoder, 0xF3));
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}
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if (attribs & (ZYDIS_ATTRIB_HAS_REPNE | ZYDIS_ATTRIB_HAS_BOUND | ZYDIS_ATTRIB_HAS_XACQUIRE))
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{
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ZYDIS_CHECK(ZydisEmitByte(encoder, 0xF2));
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}
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if (attribs & (ZYDIS_ATTRIB_HAS_BRANCH_NOT_TAKEN | ZYDIS_ATTRIB_HAS_SEGMENT_CS))
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{
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ZYDIS_CHECK(ZydisEmitByte(encoder, 0x2E));
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}
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if (attribs & (ZYDIS_ATTRIB_HAS_BRANCH_TAKEN | ZYDIS_ATTRIB_HAS_SEGMENT_DS))
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{
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ZYDIS_CHECK(ZydisEmitByte(encoder, 0x3E));
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}
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if (attribs & ZYDIS_ATTRIB_HAS_SEGMENT_SS)
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{
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ZYDIS_CHECK(ZydisEmitByte(encoder, 0x36));
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}
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if (attribs & ZYDIS_ATTRIB_HAS_SEGMENT_ES)
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{
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ZYDIS_CHECK(ZydisEmitByte(encoder, 0x26));
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}
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if (attribs & ZYDIS_ATTRIB_HAS_SEGMENT_FS)
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{
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ZYDIS_CHECK(ZydisEmitByte(encoder, 0x64));
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}
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if (attribs & ZYDIS_ATTRIB_HAS_SEGMENT_GS)
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{
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ZYDIS_CHECK(ZydisEmitByte(encoder, 0x65));
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}
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if (attribs & ZYDIS_ATTRIB_HAS_OPERANDSIZE)
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{
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ZYDIS_CHECK(ZydisEmitByte(encoder, 0x66));
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}
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if (attribs & ZYDIS_ATTRIB_HAS_ADDRESSSIZE)
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{
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ZYDIS_CHECK(ZydisEmitByte(encoder, 0x67));
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}
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return ZYDIS_STATUS_SUCCESS;
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}
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static ZydisStatus ZydisEncodeREX(ZydisInstructionEncoder *encoder)
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{
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ZYDIS_ASSERT(encoder);
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ZYDIS_CHECK(ZydisEmitByte(
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encoder,
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0x40 |
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(encoder->info->details.rex.W & 0x01) << 3 |
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(encoder->info->details.rex.R & 0x01) << 2 |
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(encoder->info->details.rex.X & 0x01) << 1 |
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(encoder->info->details.rex.B & 0x01) << 0
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));
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return ZYDIS_STATUS_SUCCESS;
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}
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static ZydisStatus ZydisEncodeVEX(ZydisInstructionEncoder *encoder)
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{
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ZYDIS_ASSERT(encoder);
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// Write opcode.
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uint8_t opcode = encoder->info->details.vex.data[0];
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ZYDIS_CHECK(ZydisEmitByte(encoder, opcode));
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// Write prefix' "operands".
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switch (opcode)
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{
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case 0xC4:
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ZYDIS_CHECK(ZydisEmitByte(
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encoder,
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(encoder->info->details.vex.R & 0x01) << 7 |
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(encoder->info->details.vex.X & 0x01) << 6 |
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(encoder->info->details.vex.B & 0x01) << 5 |
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(encoder->info->details.vex.m_mmmm & 0x1F) << 0
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));
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ZYDIS_CHECK(ZydisEmitByte(
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encoder,
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(encoder->info->details.vex.W & 0x01) << 7 |
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(encoder->info->details.vex.vvvv & 0x0F) << 3 |
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(encoder->info->details.vex.L & 0x01) << 2 |
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(encoder->info->details.vex.pp & 0x03) << 0
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));
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break;
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case 0xC5:
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ZYDIS_CHECK(ZydisEmitByte(
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encoder,
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(encoder->info->details.vex.R & 0x01) << 7 |
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(encoder->info->details.vex.vvvv & 0x0F) << 3 |
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(encoder->info->details.vex.L & 0x01) << 2 |
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(encoder->info->details.vex.pp & 0x03) << 0
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));
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break;
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default:
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ZYDIS_UNREACHABLE; // TODO: return error instead
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}
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return ZYDIS_STATUS_SUCCESS;
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}
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static ZydisStatus ZydisEncodeEVEX(ZydisInstructionEncoder *encoder)
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{
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ZYDIS_ASSERT(encoder);
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ZYDIS_CHECK(ZydisEmitByte(encoder, 0x62));
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ZYDIS_CHECK(ZydisEmitByte(
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encoder,
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(encoder->info->details.evex.R & 0x01) << 7 |
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(encoder->info->details.evex.X & 0x01) << 6 |
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(encoder->info->details.evex.B & 0x01) << 5 |
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(encoder->info->details.evex.R2 & 0x01) << 4 |
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(encoder->info->details.evex.mm & 0x03) << 0
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));
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ZYDIS_CHECK(ZydisEmitByte(
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encoder,
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(encoder->info->details.evex.W & 0x01) << 7 |
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(encoder->info->details.evex.vvvv & 0x0F) << 3 |
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(encoder->info->details.evex.pp & 0x03) << 0
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));
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ZYDIS_CHECK(ZydisEmitByte(
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encoder,
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(encoder->info->details.evex.z & 0x01) << 7 |
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(encoder->info->details.evex.L2 & 0x01) << 6 |
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(encoder->info->details.evex.L & 0x01) << 5 |
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(encoder->info->details.evex.b & 0x01) << 4 |
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(encoder->info->details.evex.V2 & 0x01) << 3 |
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(encoder->info->details.evex.aaa & 0x07) << 0
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));
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return ZYDIS_STATUS_SUCCESS;
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}
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static ZydisStatus ZydisEncodeXOP(ZydisInstructionEncoder *encoder)
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{
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ZYDIS_ASSERT(encoder);
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ZYDIS_CHECK(ZydisEmitByte(encoder, 0x8F));
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ZYDIS_CHECK(ZydisEmitByte(
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encoder,
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(encoder->info->details.xop.R & 0x01) << 7 |
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(encoder->info->details.xop.X & 0x01) << 6 |
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(encoder->info->details.xop.B & 0x01) << 5 |
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(encoder->info->details.xop.m_mmmm & 0x1F) << 0
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));
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ZYDIS_CHECK(ZydisEmitByte(
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encoder,
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(encoder->info->details.xop.W & 0x01) << 7 |
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(encoder->info->details.xop.vvvv & 0x0F) << 3 |
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(encoder->info->details.xop.L & 0x01) << 2 |
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(encoder->info->details.xop.pp & 0x03) << 0
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));
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return ZYDIS_STATUS_SUCCESS;
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}
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/* ============================================================================================== */
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/* Implementation of public functions */
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/* ============================================================================================== */
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ZydisStatus ZydisEncoderEncodeInstruction(void* buffer, size_t bufferLen,
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ZydisInstructionInfo* info)
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{
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if (!info) return ZYDIS_STATUS_INVALID_PARAMETER;
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if (!buffer || !bufferLen) return ZYDIS_STATUS_INSUFFICIENT_BUFFER_SIZE;
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ZydisInstructionEncoder encoder;
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encoder.buffer = (uint8_t*)buffer;
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encoder.bufferLen = bufferLen;
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encoder.writeOffs = 0;
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encoder.info = info;
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ZYDIS_CHECK(ZydisEncodeLegacyPrefixes(&encoder));
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return ZYDIS_STATUS_SUCCESS;
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}
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