265 lines
9.9 KiB
C
265 lines
9.9 KiB
C
/***************************************************************************************************
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Zyan Disassembler Library (Zydis)
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Original Author : Florian Bernd
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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***************************************************************************************************/
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/**
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* @file
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* Demonstrates basic hooking functionality of the `ZydisFormatter` class and the ability
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* to completely omit specific operands.
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*
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* This example demonstrates the hooking functionality of the `ZydisFormatter` class by
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* rewriting the mnemonics of `(V)CMPPS` and `(V)CMPPD` to their corresponding alias-forms (based
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* on the condition encoded in the immediate operand).
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*/
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#include <inttypes.h>
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#include <Zycore/Format.h>
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#include <Zycore/LibC.h>
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#include <Zydis/Zydis.h>
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/* ============================================================================================== */
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/* Static data */
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/* ============================================================================================== */
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/**
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* Static array with the condition-code strings.
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*/
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static const char* const CONDITION_CODE_STRINGS[0x20] =
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{
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/*00*/ "eq",
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/*01*/ "lt",
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/*02*/ "le",
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/*03*/ "unord",
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/*04*/ "neq",
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/*05*/ "nlt",
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/*06*/ "nle",
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/*07*/ "ord",
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/*08*/ "eq_uq",
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/*09*/ "nge",
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/*0A*/ "ngt",
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/*0B*/ "false",
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/*0C*/ "oq",
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/*0D*/ "ge",
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/*0E*/ "gt",
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/*0F*/ "true",
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/*10*/ "eq_os",
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/*11*/ "lt_oq",
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/*12*/ "le_oq",
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/*13*/ "unord_s",
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/*14*/ "neq_us",
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/*15*/ "nlt_uq",
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/*16*/ "nle_uq",
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/*17*/ "ord_s",
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/*18*/ "eq_us",
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/*19*/ "nge_uq",
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/*1A*/ "ngt_uq",
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/*1B*/ "false_os",
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/*1C*/ "neq_os",
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/*1D*/ "ge_oq",
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/*1E*/ "gt_oq",
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/*1F*/ "true_us"
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};
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/* ============================================================================================== */
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/* Enums and Types */
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/* ============================================================================================== */
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/**
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* Custom user data struct for the formatter.
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*/
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typedef struct ZydisCustomUserData_
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{
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ZyanBool omit_immediate;
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} ZydisCustomUserData;
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/* ============================================================================================== */
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/* Hook callbacks */
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/* ============================================================================================== */
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ZydisFormatterFunc default_print_mnemonic;
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static ZyanStatus ZydisFormatterPrintMnemonic(const ZydisFormatter* formatter,
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ZydisFormatterBuffer* buffer, ZydisFormatterContext* context)
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{
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// We use the user-data to pass data to the `ZydisFormatterFormatOperandImm` function
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ZydisCustomUserData* user_data = (ZydisCustomUserData*)context->user_data;
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user_data->omit_immediate = ZYAN_TRUE;
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// Rewrite the instruction-mnemonic for the given instructions
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if (context->instruction->operand_count &&
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context->instruction->operands[context->instruction->operand_count - 1].type ==
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ZYDIS_OPERAND_TYPE_IMMEDIATE)
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{
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// Retrieve the `ZyanString` instance of the formatter-buffer
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ZyanString* string;
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ZYAN_CHECK(ZydisFormatterBufferGetString(buffer, &string));
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const ZyanU8 condition_code = (ZyanU8)context->instruction->operands[
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context->instruction->operand_count - 1].imm.value.u;
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switch (context->instruction->mnemonic)
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{
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case ZYDIS_MNEMONIC_CMPPS:
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if (condition_code < 0x08)
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{
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ZYAN_CHECK(ZydisFormatterBufferAppend(buffer, ZYDIS_TOKEN_MNEMONIC));
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return ZyanStringAppendFormat(string, "cmp%sps",
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CONDITION_CODE_STRINGS[condition_code]);
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}
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break;
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case ZYDIS_MNEMONIC_CMPPD:
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if (condition_code < 0x08)
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{
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ZYAN_CHECK(ZydisFormatterBufferAppend(buffer, ZYDIS_TOKEN_MNEMONIC));
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return ZyanStringAppendFormat(string, "cmp%spd",
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CONDITION_CODE_STRINGS[condition_code]);
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}
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break;
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case ZYDIS_MNEMONIC_VCMPPS:
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if (condition_code < 0x20)
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{
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ZYAN_CHECK(ZydisFormatterBufferAppend(buffer, ZYDIS_TOKEN_MNEMONIC));
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return ZyanStringAppendFormat(string, "vcmp%sps",
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CONDITION_CODE_STRINGS[condition_code]);
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}
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break;
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case ZYDIS_MNEMONIC_VCMPPD:
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if (condition_code < 0x20)
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{
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ZYAN_CHECK(ZydisFormatterBufferAppend(buffer, ZYDIS_TOKEN_MNEMONIC));
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return ZyanStringAppendFormat(string, "vcmp%spd",
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CONDITION_CODE_STRINGS[condition_code]);
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}
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break;
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default:
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break;
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}
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}
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// We did not rewrite the instruction-mnemonic. Signal the `ZydisFormatterFormatOperandImm`
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// function not to omit the operand
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user_data->omit_immediate = ZYAN_FALSE;
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// Default mnemonic printing
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return default_print_mnemonic(formatter, buffer, context);
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}
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/* ---------------------------------------------------------------------------------------------- */
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ZydisFormatterFunc default_format_operand_imm;
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static ZyanStatus ZydisFormatterFormatOperandIMM(const ZydisFormatter* formatter,
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ZydisFormatterBuffer* buffer, ZydisFormatterContext* context)
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{
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// The `ZydisFormatterFormatMnemonic` sinals us to omit the immediate (condition-code)
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// operand, because it got replaced by the alias-mnemonic
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const ZydisCustomUserData* user_data = (ZydisCustomUserData*)context->user_data;
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if (user_data->omit_immediate)
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{
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return ZYDIS_STATUS_SKIP_TOKEN;
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}
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// Default immediate formatting
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return default_format_operand_imm(formatter, buffer, context);
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}
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/* ---------------------------------------------------------------------------------------------- */
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/* ============================================================================================== */
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/* Helper functions */
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/* ============================================================================================== */
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static void DisassembleBuffer(ZydisDecoder* decoder, ZyanU8* data, ZyanUSize length,
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ZyanBool install_hooks)
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{
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ZydisFormatter formatter;
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ZydisFormatterInit(&formatter, ZYDIS_FORMATTER_STYLE_INTEL);
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ZydisFormatterSetProperty(&formatter, ZYDIS_FORMATTER_PROP_FORCE_SEGMENT, ZYAN_TRUE);
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ZydisFormatterSetProperty(&formatter, ZYDIS_FORMATTER_PROP_FORCE_SIZE, ZYAN_TRUE);
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if (install_hooks)
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{
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default_print_mnemonic = (ZydisFormatterFunc)&ZydisFormatterPrintMnemonic;
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ZydisFormatterSetHook(&formatter, ZYDIS_FORMATTER_FUNC_PRINT_MNEMONIC,
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(const void**)&default_print_mnemonic);
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default_format_operand_imm = (ZydisFormatterFunc)&ZydisFormatterFormatOperandIMM;
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ZydisFormatterSetHook(&formatter, ZYDIS_FORMATTER_FUNC_FORMAT_OPERAND_IMM,
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(const void**)&default_format_operand_imm);
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}
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ZyanU64 runtime_address = 0x007FFFFFFF400000;
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ZydisDecodedInstruction instruction;
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ZydisCustomUserData user_data;
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char buffer[256];
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while (ZYAN_SUCCESS(ZydisDecoderDecodeBuffer(decoder, data, length, &instruction)))
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{
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ZYAN_PRINTF("%016" PRIX64 " ", runtime_address);
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ZydisFormatterFormatInstructionEx(&formatter, &instruction, &buffer[0], sizeof(buffer),
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runtime_address, &user_data);
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ZYAN_PRINTF(" %s\n", &buffer[0]);
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data += instruction.length;
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length -= instruction.length;
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runtime_address += instruction.length;
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}
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}
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/* ============================================================================================== */
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/* Entry point */
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/* ============================================================================================== */
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int main(void)
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{
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if (ZydisGetVersion() != ZYDIS_VERSION)
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{
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fputs("Invalid zydis version\n", ZYAN_STDERR);
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return EXIT_FAILURE;
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}
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ZyanU8 data[] =
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{
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// nop
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0x90,
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// cmpps xmm1, xmm4, 0x03
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0x0F, 0xC2, 0xCC, 0x03,
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// vcmppd xmm1, xmm2, xmm3, 0x17
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0xC5, 0xE9, 0xC2, 0xCB, 0x17,
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// vcmpps k2 {k7}, zmm2, dword ptr ds:[rax + rbx*4 + 0x100] {1to16}, 0x0F
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0x62, 0xF1, 0x6C, 0x5F, 0xC2, 0x54, 0x98, 0x40, 0x0F
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};
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ZydisDecoder decoder;
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ZydisDecoderInit(&decoder, ZYDIS_MACHINE_MODE_LONG_64, ZYDIS_ADDRESS_WIDTH_64);
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DisassembleBuffer(&decoder, &data[0], sizeof(data), ZYAN_FALSE);
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ZYAN_PUTS("");
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DisassembleBuffer(&decoder, &data[0], sizeof(data), ZYAN_TRUE);
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return 0;
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}
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/* ============================================================================================== */
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