/*
 * Copyright (c) 2018-2019 Atmosphère-NX
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * Adapted by DarkLordZach for use/interaction with yuzu
 *
 * Modifications Copyright 2019 yuzu emulator team
 * Licensed under GPLv2 or any later version
 * Refer to the license.txt file included.
 */

#include "common/assert.h"
#include "common/scope_exit.h"
#include "core/memory/dmnt_cheat_types.h"
#include "core/memory/dmnt_cheat_vm.h"

namespace Memory {

void DmntCheatVm::DebugLog(u32 log_id, u64 value) {
    callbacks->DebugLog(static_cast<u8>(log_id), value);
}

void DmntCheatVm::LogOpcode(const CheatVmOpcode& opcode) {
    switch (opcode.opcode) {
    case CheatVmOpcodeType_StoreStatic:
        this->LogToDebugFile("Opcode: Store Static\n");
        this->LogToDebugFile("Bit Width: %x\n", opcode.store_static.bit_width);
        this->LogToDebugFile("Mem Type:  %x\n", opcode.store_static.mem_type);
        this->LogToDebugFile("Reg Idx:   %x\n", opcode.store_static.offset_register);
        this->LogToDebugFile("Rel Addr:  %lx\n", opcode.store_static.rel_address);
        this->LogToDebugFile("Value:     %lx\n", opcode.store_static.value.bit64);
        break;
    case CheatVmOpcodeType_BeginConditionalBlock:
        this->LogToDebugFile("Opcode: Begin Conditional\n");
        this->LogToDebugFile("Bit Width: %x\n", opcode.begin_cond.bit_width);
        this->LogToDebugFile("Mem Type:  %x\n", opcode.begin_cond.mem_type);
        this->LogToDebugFile("Cond Type: %x\n", opcode.begin_cond.cond_type);
        this->LogToDebugFile("Rel Addr:  %lx\n", opcode.begin_cond.rel_address);
        this->LogToDebugFile("Value:     %lx\n", opcode.begin_cond.value.bit64);
        break;
    case CheatVmOpcodeType_EndConditionalBlock:
        this->LogToDebugFile("Opcode: End Conditional\n");
        break;
    case CheatVmOpcodeType_ControlLoop:
        if (opcode.ctrl_loop.start_loop) {
            this->LogToDebugFile("Opcode: Start Loop\n");
            this->LogToDebugFile("Reg Idx:   %x\n", opcode.ctrl_loop.reg_index);
            this->LogToDebugFile("Num Iters: %x\n", opcode.ctrl_loop.num_iters);
        } else {
            this->LogToDebugFile("Opcode: End Loop\n");
            this->LogToDebugFile("Reg Idx:   %x\n", opcode.ctrl_loop.reg_index);
        }
        break;
    case CheatVmOpcodeType_LoadRegisterStatic:
        this->LogToDebugFile("Opcode: Load Register Static\n");
        this->LogToDebugFile("Reg Idx:   %x\n", opcode.ldr_static.reg_index);
        this->LogToDebugFile("Value:     %lx\n", opcode.ldr_static.value);
        break;
    case CheatVmOpcodeType_LoadRegisterMemory:
        this->LogToDebugFile("Opcode: Load Register Memory\n");
        this->LogToDebugFile("Bit Width: %x\n", opcode.ldr_memory.bit_width);
        this->LogToDebugFile("Reg Idx:   %x\n", opcode.ldr_memory.reg_index);
        this->LogToDebugFile("Mem Type:  %x\n", opcode.ldr_memory.mem_type);
        this->LogToDebugFile("From Reg:  %d\n", opcode.ldr_memory.load_from_reg);
        this->LogToDebugFile("Rel Addr:  %lx\n", opcode.ldr_memory.rel_address);
        break;
    case CheatVmOpcodeType_StoreStaticToAddress:
        this->LogToDebugFile("Opcode: Store Static to Address\n");
        this->LogToDebugFile("Bit Width: %x\n", opcode.str_static.bit_width);
        this->LogToDebugFile("Reg Idx:   %x\n", opcode.str_static.reg_index);
        if (opcode.str_static.add_offset_reg) {
            this->LogToDebugFile("O Reg Idx: %x\n", opcode.str_static.offset_reg_index);
        }
        this->LogToDebugFile("Incr Reg:  %d\n", opcode.str_static.increment_reg);
        this->LogToDebugFile("Value:     %lx\n", opcode.str_static.value);
        break;
    case CheatVmOpcodeType_PerformArithmeticStatic:
        this->LogToDebugFile("Opcode: Perform Static Arithmetic\n");
        this->LogToDebugFile("Bit Width: %x\n", opcode.perform_math_static.bit_width);
        this->LogToDebugFile("Reg Idx:   %x\n", opcode.perform_math_static.reg_index);
        this->LogToDebugFile("Math Type: %x\n", opcode.perform_math_static.math_type);
        this->LogToDebugFile("Value:     %lx\n", opcode.perform_math_static.value);
        break;
    case CheatVmOpcodeType_BeginKeypressConditionalBlock:
        this->LogToDebugFile("Opcode: Begin Keypress Conditional\n");
        this->LogToDebugFile("Key Mask:  %x\n", opcode.begin_keypress_cond.key_mask);
        break;
    case CheatVmOpcodeType_PerformArithmeticRegister:
        this->LogToDebugFile("Opcode: Perform Register Arithmetic\n");
        this->LogToDebugFile("Bit Width: %x\n", opcode.perform_math_reg.bit_width);
        this->LogToDebugFile("Dst Idx:   %x\n", opcode.perform_math_reg.dst_reg_index);
        this->LogToDebugFile("Src1 Idx:  %x\n", opcode.perform_math_reg.src_reg_1_index);
        if (opcode.perform_math_reg.has_immediate) {
            this->LogToDebugFile("Value:     %lx\n", opcode.perform_math_reg.value.bit64);
        } else {
            this->LogToDebugFile("Src2 Idx:  %x\n", opcode.perform_math_reg.src_reg_2_index);
        }
        break;
    case CheatVmOpcodeType_StoreRegisterToAddress:
        this->LogToDebugFile("Opcode: Store Register to Address\n");
        this->LogToDebugFile("Bit Width: %x\n", opcode.str_register.bit_width);
        this->LogToDebugFile("S Reg Idx: %x\n", opcode.str_register.str_reg_index);
        this->LogToDebugFile("A Reg Idx: %x\n", opcode.str_register.addr_reg_index);
        this->LogToDebugFile("Incr Reg:  %d\n", opcode.str_register.increment_reg);
        switch (opcode.str_register.ofs_type) {
        case StoreRegisterOffsetType_None:
            break;
        case StoreRegisterOffsetType_Reg:
            this->LogToDebugFile("O Reg Idx: %x\n", opcode.str_register.ofs_reg_index);
            break;
        case StoreRegisterOffsetType_Imm:
            this->LogToDebugFile("Rel Addr:  %lx\n", opcode.str_register.rel_address);
            break;
        case StoreRegisterOffsetType_MemReg:
            this->LogToDebugFile("Mem Type:  %x\n", opcode.str_register.mem_type);
            break;
        case StoreRegisterOffsetType_MemImm:
        case StoreRegisterOffsetType_MemImmReg:
            this->LogToDebugFile("Mem Type:  %x\n", opcode.str_register.mem_type);
            this->LogToDebugFile("Rel Addr:  %lx\n", opcode.str_register.rel_address);
            break;
        }
        break;
    case CheatVmOpcodeType_BeginRegisterConditionalBlock:
        this->LogToDebugFile("Opcode: Begin Register Conditional\n");
        this->LogToDebugFile("Bit Width: %x\n", opcode.begin_reg_cond.bit_width);
        this->LogToDebugFile("Cond Type: %x\n", opcode.begin_reg_cond.cond_type);
        this->LogToDebugFile("V Reg Idx: %x\n", opcode.begin_reg_cond.val_reg_index);
        switch (opcode.begin_reg_cond.comp_type) {
        case CompareRegisterValueType_StaticValue:
            this->LogToDebugFile("Comp Type: Static Value\n");
            this->LogToDebugFile("Value:     %lx\n", opcode.begin_reg_cond.value.bit64);
            break;
        case CompareRegisterValueType_OtherRegister:
            this->LogToDebugFile("Comp Type: Other Register\n");
            this->LogToDebugFile("X Reg Idx: %x\n", opcode.begin_reg_cond.other_reg_index);
            break;
        case CompareRegisterValueType_MemoryRelAddr:
            this->LogToDebugFile("Comp Type: Memory Relative Address\n");
            this->LogToDebugFile("Mem Type:  %x\n", opcode.begin_reg_cond.mem_type);
            this->LogToDebugFile("Rel Addr:  %lx\n", opcode.begin_reg_cond.rel_address);
            break;
        case CompareRegisterValueType_MemoryOfsReg:
            this->LogToDebugFile("Comp Type: Memory Offset Register\n");
            this->LogToDebugFile("Mem Type:  %x\n", opcode.begin_reg_cond.mem_type);
            this->LogToDebugFile("O Reg Idx: %x\n", opcode.begin_reg_cond.ofs_reg_index);
            break;
        case CompareRegisterValueType_RegisterRelAddr:
            this->LogToDebugFile("Comp Type: Register Relative Address\n");
            this->LogToDebugFile("A Reg Idx: %x\n", opcode.begin_reg_cond.addr_reg_index);
            this->LogToDebugFile("Rel Addr:  %lx\n", opcode.begin_reg_cond.rel_address);
            break;
        case CompareRegisterValueType_RegisterOfsReg:
            this->LogToDebugFile("Comp Type: Register Offset Register\n");
            this->LogToDebugFile("A Reg Idx: %x\n", opcode.begin_reg_cond.addr_reg_index);
            this->LogToDebugFile("O Reg Idx: %x\n", opcode.begin_reg_cond.ofs_reg_index);
            break;
        }
        break;
    case CheatVmOpcodeType_SaveRestoreRegister:
        this->LogToDebugFile("Opcode: Save or Restore Register\n");
        this->LogToDebugFile("Dst Idx:   %x\n", opcode.save_restore_reg.dst_index);
        this->LogToDebugFile("Src Idx:   %x\n", opcode.save_restore_reg.src_index);
        this->LogToDebugFile("Op Type:   %d\n", opcode.save_restore_reg.op_type);
        break;
    case CheatVmOpcodeType_SaveRestoreRegisterMask:
        this->LogToDebugFile("Opcode: Save or Restore Register Mask\n");
        this->LogToDebugFile("Op Type:   %d\n", opcode.save_restore_regmask.op_type);
        for (size_t i = 0; i < NumRegisters; i++) {
            this->LogToDebugFile("Act[%02x]:   %d\n", i,
                                 opcode.save_restore_regmask.should_operate[i]);
        }
        break;
    case CheatVmOpcodeType_DebugLog:
        this->LogToDebugFile("Opcode: Debug Log\n");
        this->LogToDebugFile("Bit Width: %x\n", opcode.debug_log.bit_width);
        this->LogToDebugFile("Log ID:    %x\n", opcode.debug_log.log_id);
        this->LogToDebugFile("Val Type:  %x\n", opcode.debug_log.val_type);
        switch (opcode.debug_log.val_type) {
        case DebugLogValueType_RegisterValue:
            this->LogToDebugFile("Val Type:  Register Value\n");
            this->LogToDebugFile("X Reg Idx: %x\n", opcode.debug_log.val_reg_index);
            break;
        case DebugLogValueType_MemoryRelAddr:
            this->LogToDebugFile("Val Type:  Memory Relative Address\n");
            this->LogToDebugFile("Mem Type:  %x\n", opcode.debug_log.mem_type);
            this->LogToDebugFile("Rel Addr:  %lx\n", opcode.debug_log.rel_address);
            break;
        case DebugLogValueType_MemoryOfsReg:
            this->LogToDebugFile("Val Type:  Memory Offset Register\n");
            this->LogToDebugFile("Mem Type:  %x\n", opcode.debug_log.mem_type);
            this->LogToDebugFile("O Reg Idx: %x\n", opcode.debug_log.ofs_reg_index);
            break;
        case DebugLogValueType_RegisterRelAddr:
            this->LogToDebugFile("Val Type:  Register Relative Address\n");
            this->LogToDebugFile("A Reg Idx: %x\n", opcode.debug_log.addr_reg_index);
            this->LogToDebugFile("Rel Addr:  %lx\n", opcode.debug_log.rel_address);
            break;
        case DebugLogValueType_RegisterOfsReg:
            this->LogToDebugFile("Val Type:  Register Offset Register\n");
            this->LogToDebugFile("A Reg Idx: %x\n", opcode.debug_log.addr_reg_index);
            this->LogToDebugFile("O Reg Idx: %x\n", opcode.debug_log.ofs_reg_index);
            break;
        }
    default:
        this->LogToDebugFile("Unknown opcode: %x\n", opcode.opcode);
        break;
    }
}

DmntCheatVm::Callbacks::~Callbacks() = default;

bool DmntCheatVm::DecodeNextOpcode(CheatVmOpcode& out) {
    /* If we've ever seen a decode failure, return false. */
    bool valid = this->decode_success;
    CheatVmOpcode opcode = {};
    SCOPE_EXIT({
        this->decode_success &= valid;
        if (valid) {
            out = opcode;
        }
    });

    /* Helper function for getting instruction dwords. */
    auto GetNextDword = [&]() {
        if (this->instruction_ptr >= this->num_opcodes) {
            valid = false;
            return static_cast<u32>(0);
        }
        return this->program[this->instruction_ptr++];
    };

    /* Helper function for parsing a VmInt. */
    auto GetNextVmInt = [&](const u32 bit_width) {
        VmInt val = {0};

        const u32 first_dword = GetNextDword();
        switch (bit_width) {
        case 1:
            val.bit8 = (u8)first_dword;
            break;
        case 2:
            val.bit16 = (u16)first_dword;
            break;
        case 4:
            val.bit32 = first_dword;
            break;
        case 8:
            val.bit64 = (((u64)first_dword) << 32ul) | ((u64)GetNextDword());
            break;
        }

        return val;
    };

    /* Read opcode. */
    const u32 first_dword = GetNextDword();
    if (!valid) {
        return valid;
    }

    opcode.opcode = (CheatVmOpcodeType)(((first_dword >> 28) & 0xF));
    if (opcode.opcode >= CheatVmOpcodeType_ExtendedWidth) {
        opcode.opcode =
            (CheatVmOpcodeType)((((u32)opcode.opcode) << 4) | ((first_dword >> 24) & 0xF));
    }
    if (opcode.opcode >= CheatVmOpcodeType_DoubleExtendedWidth) {
        opcode.opcode =
            (CheatVmOpcodeType)((((u32)opcode.opcode) << 4) | ((first_dword >> 20) & 0xF));
    }

    /* detect condition start. */
    switch (opcode.opcode) {
    case CheatVmOpcodeType_BeginConditionalBlock:
    case CheatVmOpcodeType_BeginKeypressConditionalBlock:
    case CheatVmOpcodeType_BeginRegisterConditionalBlock:
        opcode.begin_conditional_block = true;
        break;
    default:
        opcode.begin_conditional_block = false;
        break;
    }

    switch (opcode.opcode) {
    case CheatVmOpcodeType_StoreStatic: {
        /* 0TMR00AA AAAAAAAA YYYYYYYY (YYYYYYYY) */
        /* Read additional words. */
        const u32 second_dword = GetNextDword();
        opcode.store_static.bit_width = (first_dword >> 24) & 0xF;
        opcode.store_static.mem_type = (MemoryAccessType)((first_dword >> 20) & 0xF);
        opcode.store_static.offset_register = ((first_dword >> 16) & 0xF);
        opcode.store_static.rel_address = ((u64)(first_dword & 0xFF) << 32ul) | ((u64)second_dword);
        opcode.store_static.value = GetNextVmInt(opcode.store_static.bit_width);
    } break;
    case CheatVmOpcodeType_BeginConditionalBlock: {
        /* 1TMC00AA AAAAAAAA YYYYYYYY (YYYYYYYY) */
        /* Read additional words. */
        const u32 second_dword = GetNextDword();
        opcode.begin_cond.bit_width = (first_dword >> 24) & 0xF;
        opcode.begin_cond.mem_type = (MemoryAccessType)((first_dword >> 20) & 0xF);
        opcode.begin_cond.cond_type = (ConditionalComparisonType)((first_dword >> 16) & 0xF);
        opcode.begin_cond.rel_address = ((u64)(first_dword & 0xFF) << 32ul) | ((u64)second_dword);
        opcode.begin_cond.value = GetNextVmInt(opcode.store_static.bit_width);
    } break;
    case CheatVmOpcodeType_EndConditionalBlock: {
        /* 20000000 */
        /* There's actually nothing left to process here! */
    } break;
    case CheatVmOpcodeType_ControlLoop: {
        /* 300R0000 VVVVVVVV */
        /* 310R0000 */
        /* Parse register, whether loop start or loop end. */
        opcode.ctrl_loop.start_loop = ((first_dword >> 24) & 0xF) == 0;
        opcode.ctrl_loop.reg_index = ((first_dword >> 20) & 0xF);

        /* Read number of iters if loop start. */
        if (opcode.ctrl_loop.start_loop) {
            opcode.ctrl_loop.num_iters = GetNextDword();
        }
    } break;
    case CheatVmOpcodeType_LoadRegisterStatic: {
        /* 400R0000 VVVVVVVV VVVVVVVV */
        /* Read additional words. */
        opcode.ldr_static.reg_index = ((first_dword >> 16) & 0xF);
        opcode.ldr_static.value = (((u64)GetNextDword()) << 32ul) | ((u64)GetNextDword());
    } break;
    case CheatVmOpcodeType_LoadRegisterMemory: {
        /* 5TMRI0AA AAAAAAAA */
        /* Read additional words. */
        const u32 second_dword = GetNextDword();
        opcode.ldr_memory.bit_width = (first_dword >> 24) & 0xF;
        opcode.ldr_memory.mem_type = (MemoryAccessType)((first_dword >> 20) & 0xF);
        opcode.ldr_memory.reg_index = ((first_dword >> 16) & 0xF);
        opcode.ldr_memory.load_from_reg = ((first_dword >> 12) & 0xF) != 0;
        opcode.ldr_memory.rel_address = ((u64)(first_dword & 0xFF) << 32ul) | ((u64)second_dword);
    } break;
    case CheatVmOpcodeType_StoreStaticToAddress: {
        /* 6T0RIor0 VVVVVVVV VVVVVVVV */
        /* Read additional words. */
        opcode.str_static.bit_width = (first_dword >> 24) & 0xF;
        opcode.str_static.reg_index = ((first_dword >> 16) & 0xF);
        opcode.str_static.increment_reg = ((first_dword >> 12) & 0xF) != 0;
        opcode.str_static.add_offset_reg = ((first_dword >> 8) & 0xF) != 0;
        opcode.str_static.offset_reg_index = ((first_dword >> 4) & 0xF);
        opcode.str_static.value = (((u64)GetNextDword()) << 32ul) | ((u64)GetNextDword());
    } break;
    case CheatVmOpcodeType_PerformArithmeticStatic: {
        /* 7T0RC000 VVVVVVVV */
        /* Read additional words. */
        opcode.perform_math_static.bit_width = (first_dword >> 24) & 0xF;
        opcode.perform_math_static.reg_index = ((first_dword >> 16) & 0xF);
        opcode.perform_math_static.math_type = (RegisterArithmeticType)((first_dword >> 12) & 0xF);
        opcode.perform_math_static.value = GetNextDword();
    } break;
    case CheatVmOpcodeType_BeginKeypressConditionalBlock: {
        /* 8kkkkkkk */
        /* Just parse the mask. */
        opcode.begin_keypress_cond.key_mask = first_dword & 0x0FFFFFFF;
    } break;
    case CheatVmOpcodeType_PerformArithmeticRegister: {
        /* 9TCRSIs0 (VVVVVVVV (VVVVVVVV)) */
        opcode.perform_math_reg.bit_width = (first_dword >> 24) & 0xF;
        opcode.perform_math_reg.math_type = (RegisterArithmeticType)((first_dword >> 20) & 0xF);
        opcode.perform_math_reg.dst_reg_index = ((first_dword >> 16) & 0xF);
        opcode.perform_math_reg.src_reg_1_index = ((first_dword >> 12) & 0xF);
        opcode.perform_math_reg.has_immediate = ((first_dword >> 8) & 0xF) != 0;
        if (opcode.perform_math_reg.has_immediate) {
            opcode.perform_math_reg.src_reg_2_index = 0;
            opcode.perform_math_reg.value = GetNextVmInt(opcode.perform_math_reg.bit_width);
        } else {
            opcode.perform_math_reg.src_reg_2_index = ((first_dword >> 4) & 0xF);
        }
    } break;
    case CheatVmOpcodeType_StoreRegisterToAddress: {
        /* ATSRIOxa (aaaaaaaa) */
        /* A = opcode 10 */
        /* T = bit width */
        /* S = src register index */
        /* R = address register index */
        /* I = 1 if increment address register, 0 if not increment address register */
        /* O = offset type, 0 = None, 1 = Register, 2 = Immediate, 3 = Memory Region,
                4 = Memory Region + Relative Address (ignore address register), 5 = Memory Region +
           Relative Address */
        /* x = offset register (for offset type 1), memory type (for offset type 3) */
        /* a = relative address (for offset type 2+3) */
        opcode.str_register.bit_width = (first_dword >> 24) & 0xF;
        opcode.str_register.str_reg_index = ((first_dword >> 20) & 0xF);
        opcode.str_register.addr_reg_index = ((first_dword >> 16) & 0xF);
        opcode.str_register.increment_reg = ((first_dword >> 12) & 0xF) != 0;
        opcode.str_register.ofs_type = (StoreRegisterOffsetType)(((first_dword >> 8) & 0xF));
        opcode.str_register.ofs_reg_index = ((first_dword >> 4) & 0xF);
        switch (opcode.str_register.ofs_type) {
        case StoreRegisterOffsetType_None:
        case StoreRegisterOffsetType_Reg:
            /* Nothing more to do */
            break;
        case StoreRegisterOffsetType_Imm:
            opcode.str_register.rel_address =
                (((u64)(first_dword & 0xF) << 32ul) | ((u64)GetNextDword()));
            break;
        case StoreRegisterOffsetType_MemReg:
            opcode.str_register.mem_type = (MemoryAccessType)((first_dword >> 4) & 0xF);
            break;
        case StoreRegisterOffsetType_MemImm:
        case StoreRegisterOffsetType_MemImmReg:
            opcode.str_register.mem_type = (MemoryAccessType)((first_dword >> 4) & 0xF);
            opcode.str_register.rel_address =
                (((u64)(first_dword & 0xF) << 32ul) | ((u64)GetNextDword()));
            break;
        default:
            opcode.str_register.ofs_type = StoreRegisterOffsetType_None;
            break;
        }
    } break;
    case CheatVmOpcodeType_BeginRegisterConditionalBlock: {
        /* C0TcSX## */
        /* C0TcS0Ma aaaaaaaa */
        /* C0TcS1Mr */
        /* C0TcS2Ra aaaaaaaa */
        /* C0TcS3Rr */
        /* C0TcS400 VVVVVVVV (VVVVVVVV) */
        /* C0TcS5X0 */
        /* C0 = opcode 0xC0 */
        /* T = bit width */
        /* c = condition type. */
        /* S = source register. */
        /* X = value operand type, 0 = main/heap with relative offset, 1 = main/heap with offset
         * register, */
        /*     2 = register with relative offset, 3 = register with offset register, 4 = static
         * value, 5 = other register. */
        /* M = memory type. */
        /* R = address register. */
        /* a = relative address. */
        /* r = offset register. */
        /* X = other register. */
        /* V = value. */
        opcode.begin_reg_cond.bit_width = (first_dword >> 20) & 0xF;
        opcode.begin_reg_cond.cond_type = (ConditionalComparisonType)((first_dword >> 16) & 0xF);
        opcode.begin_reg_cond.val_reg_index = ((first_dword >> 12) & 0xF);
        opcode.begin_reg_cond.comp_type = (CompareRegisterValueType)((first_dword >> 8) & 0xF);

        switch (opcode.begin_reg_cond.comp_type) {
        case CompareRegisterValueType_StaticValue:
            opcode.begin_reg_cond.value = GetNextVmInt(opcode.begin_reg_cond.bit_width);
            break;
        case CompareRegisterValueType_OtherRegister:
            opcode.begin_reg_cond.other_reg_index = ((first_dword >> 4) & 0xF);
            break;
        case CompareRegisterValueType_MemoryRelAddr:
            opcode.begin_reg_cond.mem_type = (MemoryAccessType)((first_dword >> 4) & 0xF);
            opcode.begin_reg_cond.rel_address =
                (((u64)(first_dword & 0xF) << 32ul) | ((u64)GetNextDword()));
            break;
        case CompareRegisterValueType_MemoryOfsReg:
            opcode.begin_reg_cond.mem_type = (MemoryAccessType)((first_dword >> 4) & 0xF);
            opcode.begin_reg_cond.ofs_reg_index = (first_dword & 0xF);
            break;
        case CompareRegisterValueType_RegisterRelAddr:
            opcode.begin_reg_cond.addr_reg_index = ((first_dword >> 4) & 0xF);
            opcode.begin_reg_cond.rel_address =
                (((u64)(first_dword & 0xF) << 32ul) | ((u64)GetNextDword()));
            break;
        case CompareRegisterValueType_RegisterOfsReg:
            opcode.begin_reg_cond.addr_reg_index = ((first_dword >> 4) & 0xF);
            opcode.begin_reg_cond.ofs_reg_index = (first_dword & 0xF);
            break;
        }
    } break;
    case CheatVmOpcodeType_SaveRestoreRegister: {
        /* C10D0Sx0 */
        /* C1 = opcode 0xC1 */
        /* D = destination index. */
        /* S = source index. */
        /* x = 3 if clearing reg, 2 if clearing saved value, 1 if saving a register, 0 if restoring
         * a register. */
        /* NOTE: If we add more save slots later, current encoding is backwards compatible. */
        opcode.save_restore_reg.dst_index = (first_dword >> 16) & 0xF;
        opcode.save_restore_reg.src_index = (first_dword >> 8) & 0xF;
        opcode.save_restore_reg.op_type = (SaveRestoreRegisterOpType)((first_dword >> 4) & 0xF);
    } break;
    case CheatVmOpcodeType_SaveRestoreRegisterMask: {
        /* C2x0XXXX */
        /* C2 = opcode 0xC2 */
        /* x = 3 if clearing reg, 2 if clearing saved value, 1 if saving, 0 if restoring. */
        /* X = 16-bit bitmask, bit i --> save or restore register i. */
        opcode.save_restore_regmask.op_type =
            (SaveRestoreRegisterOpType)((first_dword >> 20) & 0xF);
        for (size_t i = 0; i < NumRegisters; i++) {
            opcode.save_restore_regmask.should_operate[i] = (first_dword & (1u << i)) != 0;
        }
    } break;
    case CheatVmOpcodeType_DebugLog: {
        /* FFFTIX## */
        /* FFFTI0Ma aaaaaaaa */
        /* FFFTI1Mr */
        /* FFFTI2Ra aaaaaaaa */
        /* FFFTI3Rr */
        /* FFFTI4X0 */
        /* FFF = opcode 0xFFF */
        /* T = bit width. */
        /* I = log id. */
        /* X = value operand type, 0 = main/heap with relative offset, 1 = main/heap with offset
         * register, */
        /*     2 = register with relative offset, 3 = register with offset register, 4 = register
         * value. */
        /* M = memory type. */
        /* R = address register. */
        /* a = relative address. */
        /* r = offset register. */
        /* X = value register. */
        opcode.debug_log.bit_width = (first_dword >> 16) & 0xF;
        opcode.debug_log.log_id = ((first_dword >> 12) & 0xF);
        opcode.debug_log.val_type = (DebugLogValueType)((first_dword >> 8) & 0xF);

        switch (opcode.debug_log.val_type) {
        case DebugLogValueType_RegisterValue:
            opcode.debug_log.val_reg_index = ((first_dword >> 4) & 0xF);
            break;
        case DebugLogValueType_MemoryRelAddr:
            opcode.debug_log.mem_type = (MemoryAccessType)((first_dword >> 4) & 0xF);
            opcode.debug_log.rel_address =
                (((u64)(first_dword & 0xF) << 32ul) | ((u64)GetNextDword()));
            break;
        case DebugLogValueType_MemoryOfsReg:
            opcode.debug_log.mem_type = (MemoryAccessType)((first_dword >> 4) & 0xF);
            opcode.debug_log.ofs_reg_index = (first_dword & 0xF);
            break;
        case DebugLogValueType_RegisterRelAddr:
            opcode.debug_log.addr_reg_index = ((first_dword >> 4) & 0xF);
            opcode.debug_log.rel_address =
                (((u64)(first_dword & 0xF) << 32ul) | ((u64)GetNextDword()));
            break;
        case DebugLogValueType_RegisterOfsReg:
            opcode.debug_log.addr_reg_index = ((first_dword >> 4) & 0xF);
            opcode.debug_log.ofs_reg_index = (first_dword & 0xF);
            break;
        }
    } break;
    case CheatVmOpcodeType_ExtendedWidth:
    case CheatVmOpcodeType_DoubleExtendedWidth:
    default:
        /* Unrecognized instruction cannot be decoded. */
        valid = false;
        break;
    }

    /* End decoding. */
    return valid;
}

void DmntCheatVm::SkipConditionalBlock() {
    if (this->condition_depth > 0) {
        /* We want to continue until we're out of the current block. */
        const size_t desired_depth = this->condition_depth - 1;

        CheatVmOpcode skip_opcode{};
        while (this->condition_depth > desired_depth && this->DecodeNextOpcode(skip_opcode)) {
            /* Decode instructions until we see end of the current conditional block. */
            /* NOTE: This is broken in gateway's implementation. */
            /* Gateway currently checks for "0x2" instead of "0x20000000" */
            /* In addition, they do a linear scan instead of correctly decoding opcodes. */
            /* This causes issues if "0x2" appears as an immediate in the conditional block... */

            /* We also support nesting of conditional blocks, and Gateway does not. */
            if (skip_opcode.begin_conditional_block) {
                this->condition_depth++;
            } else if (skip_opcode.opcode == CheatVmOpcodeType_EndConditionalBlock) {
                this->condition_depth--;
            }
        }
    } else {
        /* Skipping, but this->condition_depth = 0. */
        /* This is an error condition. */
        /* However, I don't actually believe it is possible for this to happen. */
        /* I guess we'll throw a fatal error here, so as to encourage me to fix the VM */
        /* in the event that someone triggers it? I don't know how you'd do that. */
        UNREACHABLE_MSG("Invalid condition depth in DMNT Cheat VM");
    }
}

u64 DmntCheatVm::GetVmInt(VmInt value, u32 bit_width) {
    switch (bit_width) {
    case 1:
        return value.bit8;
    case 2:
        return value.bit16;
    case 4:
        return value.bit32;
    case 8:
        return value.bit64;
    default:
        /* Invalid bit width -> return 0. */
        return 0;
    }
}

u64 DmntCheatVm::GetCheatProcessAddress(const CheatProcessMetadata& metadata,
                                        MemoryAccessType mem_type, u64 rel_address) {
    switch (mem_type) {
    case MemoryAccessType_MainNso:
    default:
        return metadata.main_nso_extents.base + rel_address;
    case MemoryAccessType_Heap:
        return metadata.heap_extents.base + rel_address;
    }
}

void DmntCheatVm::ResetState() {
    for (size_t i = 0; i < DmntCheatVm::NumRegisters; i++) {
        this->registers[i] = 0;
        this->saved_values[i] = 0;
        this->loop_tops[i] = 0;
    }
    this->instruction_ptr = 0;
    this->condition_depth = 0;
    this->decode_success = true;
}

bool DmntCheatVm::LoadProgram(const std::vector<CheatEntry>& entries) {
    /* Reset opcode count. */
    this->num_opcodes = 0;

    for (size_t i = 0; i < entries.size(); i++) {
        if (entries[i].enabled) {
            /* Bounds check. */
            if (entries[i].definition.num_opcodes + this->num_opcodes > MaximumProgramOpcodeCount) {
                this->num_opcodes = 0;
                return false;
            }

            for (size_t n = 0; n < entries[i].definition.num_opcodes; n++) {
                this->program[this->num_opcodes++] = entries[i].definition.opcodes[n];
            }
        }
    }

    return true;
}

void DmntCheatVm::Execute(const CheatProcessMetadata& metadata) {
    CheatVmOpcode cur_opcode{};

    /* Get Keys down. */
    u64 kDown = callbacks->HidKeysDown();

    this->LogToDebugFile("Started VM execution.\n");
    this->LogToDebugFile("Main NSO:  %012lx\n", metadata.main_nso_extents.base);
    this->LogToDebugFile("Heap:      %012lx\n", metadata.main_nso_extents.base);
    this->LogToDebugFile("Keys Down: %08x\n", (u32)(kDown & 0x0FFFFFFF));

    /* Clear VM state. */
    this->ResetState();

    /* Loop until program finishes. */
    while (this->DecodeNextOpcode(cur_opcode)) {
        this->LogToDebugFile("Instruction Ptr: %04x\n", (u32)this->instruction_ptr);

        for (size_t i = 0; i < NumRegisters; i++) {
            this->LogToDebugFile("Registers[%02x]: %016lx\n", i, this->registers[i]);
        }

        for (size_t i = 0; i < NumRegisters; i++) {
            this->LogToDebugFile("SavedRegs[%02x]: %016lx\n", i, this->saved_values[i]);
        }
        this->LogOpcode(cur_opcode);

        /* Increment conditional depth, if relevant. */
        if (cur_opcode.begin_conditional_block) {
            this->condition_depth++;
        }

        switch (cur_opcode.opcode) {
        case CheatVmOpcodeType_StoreStatic: {
            /* Calculate address, write value to memory. */
            u64 dst_address = GetCheatProcessAddress(
                metadata, cur_opcode.store_static.mem_type,
                cur_opcode.store_static.rel_address +
                    this->registers[cur_opcode.store_static.offset_register]);
            u64 dst_value =
                GetVmInt(cur_opcode.store_static.value, cur_opcode.store_static.bit_width);
            switch (cur_opcode.store_static.bit_width) {
            case 1:
            case 2:
            case 4:
            case 8:
                callbacks->MemoryWrite(dst_address, &dst_value, cur_opcode.store_static.bit_width);
                break;
            }
        } break;
        case CheatVmOpcodeType_BeginConditionalBlock: {
            /* Read value from memory. */
            u64 src_address = GetCheatProcessAddress(metadata, cur_opcode.begin_cond.mem_type,
                                                     cur_opcode.begin_cond.rel_address);
            u64 src_value = 0;
            switch (cur_opcode.store_static.bit_width) {
            case 1:
            case 2:
            case 4:
            case 8:
                callbacks->MemoryRead(src_address, &src_value, cur_opcode.begin_cond.bit_width);
                break;
            }
            /* Check against condition. */
            u64 cond_value = GetVmInt(cur_opcode.begin_cond.value, cur_opcode.begin_cond.bit_width);
            bool cond_met = false;
            switch (cur_opcode.begin_cond.cond_type) {
            case ConditionalComparisonType_GT:
                cond_met = src_value > cond_value;
                break;
            case ConditionalComparisonType_GE:
                cond_met = src_value >= cond_value;
                break;
            case ConditionalComparisonType_LT:
                cond_met = src_value < cond_value;
                break;
            case ConditionalComparisonType_LE:
                cond_met = src_value <= cond_value;
                break;
            case ConditionalComparisonType_EQ:
                cond_met = src_value == cond_value;
                break;
            case ConditionalComparisonType_NE:
                cond_met = src_value != cond_value;
                break;
            }
            /* Skip conditional block if condition not met. */
            if (!cond_met) {
                this->SkipConditionalBlock();
            }
        } break;
        case CheatVmOpcodeType_EndConditionalBlock:
            /* Decrement the condition depth. */
            /* We will assume, graciously, that mismatched conditional block ends are a nop. */
            if (this->condition_depth > 0) {
                this->condition_depth--;
            }
            break;
        case CheatVmOpcodeType_ControlLoop:
            if (cur_opcode.ctrl_loop.start_loop) {
                /* Start a loop. */
                this->registers[cur_opcode.ctrl_loop.reg_index] = cur_opcode.ctrl_loop.num_iters;
                this->loop_tops[cur_opcode.ctrl_loop.reg_index] = this->instruction_ptr;
            } else {
                /* End a loop. */
                this->registers[cur_opcode.ctrl_loop.reg_index]--;
                if (this->registers[cur_opcode.ctrl_loop.reg_index] != 0) {
                    this->instruction_ptr = this->loop_tops[cur_opcode.ctrl_loop.reg_index];
                }
            }
            break;
        case CheatVmOpcodeType_LoadRegisterStatic:
            /* Set a register to a static value. */
            this->registers[cur_opcode.ldr_static.reg_index] = cur_opcode.ldr_static.value;
            break;
        case CheatVmOpcodeType_LoadRegisterMemory: {
            /* Choose source address. */
            u64 src_address;
            if (cur_opcode.ldr_memory.load_from_reg) {
                src_address = this->registers[cur_opcode.ldr_memory.reg_index] +
                              cur_opcode.ldr_memory.rel_address;
            } else {
                src_address = GetCheatProcessAddress(metadata, cur_opcode.ldr_memory.mem_type,
                                                     cur_opcode.ldr_memory.rel_address);
            }
            /* Read into register. Gateway only reads on valid bitwidth. */
            switch (cur_opcode.ldr_memory.bit_width) {
            case 1:
            case 2:
            case 4:
            case 8:
                callbacks->MemoryRead(src_address,
                                      &this->registers[cur_opcode.ldr_memory.reg_index],
                                      cur_opcode.ldr_memory.bit_width);
                break;
            }
        } break;
        case CheatVmOpcodeType_StoreStaticToAddress: {
            /* Calculate address. */
            u64 dst_address = this->registers[cur_opcode.str_static.reg_index];
            u64 dst_value = cur_opcode.str_static.value;
            if (cur_opcode.str_static.add_offset_reg) {
                dst_address += this->registers[cur_opcode.str_static.offset_reg_index];
            }
            /* Write value to memory. Gateway only writes on valid bitwidth. */
            switch (cur_opcode.str_static.bit_width) {
            case 1:
            case 2:
            case 4:
            case 8:
                callbacks->MemoryWrite(dst_address, &dst_value, cur_opcode.str_static.bit_width);
                break;
            }
            /* Increment register if relevant. */
            if (cur_opcode.str_static.increment_reg) {
                this->registers[cur_opcode.str_static.reg_index] += cur_opcode.str_static.bit_width;
            }
        } break;
        case CheatVmOpcodeType_PerformArithmeticStatic: {
            /* Do requested math. */
            switch (cur_opcode.perform_math_static.math_type) {
            case RegisterArithmeticType_Addition:
                this->registers[cur_opcode.perform_math_static.reg_index] +=
                    (u64)cur_opcode.perform_math_static.value;
                break;
            case RegisterArithmeticType_Subtraction:
                this->registers[cur_opcode.perform_math_static.reg_index] -=
                    (u64)cur_opcode.perform_math_static.value;
                break;
            case RegisterArithmeticType_Multiplication:
                this->registers[cur_opcode.perform_math_static.reg_index] *=
                    (u64)cur_opcode.perform_math_static.value;
                break;
            case RegisterArithmeticType_LeftShift:
                this->registers[cur_opcode.perform_math_static.reg_index] <<=
                    (u64)cur_opcode.perform_math_static.value;
                break;
            case RegisterArithmeticType_RightShift:
                this->registers[cur_opcode.perform_math_static.reg_index] >>=
                    (u64)cur_opcode.perform_math_static.value;
                break;
            default:
                /* Do not handle extensions here. */
                break;
            }
            /* Apply bit width. */
            switch (cur_opcode.perform_math_static.bit_width) {
            case 1:
                this->registers[cur_opcode.perform_math_static.reg_index] =
                    static_cast<u8>(this->registers[cur_opcode.perform_math_static.reg_index]);
                break;
            case 2:
                this->registers[cur_opcode.perform_math_static.reg_index] =
                    static_cast<u16>(this->registers[cur_opcode.perform_math_static.reg_index]);
                break;
            case 4:
                this->registers[cur_opcode.perform_math_static.reg_index] =
                    static_cast<u32>(this->registers[cur_opcode.perform_math_static.reg_index]);
                break;
            case 8:
                this->registers[cur_opcode.perform_math_static.reg_index] =
                    static_cast<u64>(this->registers[cur_opcode.perform_math_static.reg_index]);
                break;
            }
        } break;
        case CheatVmOpcodeType_BeginKeypressConditionalBlock:
            /* Check for keypress. */
            if ((cur_opcode.begin_keypress_cond.key_mask & kDown) !=
                cur_opcode.begin_keypress_cond.key_mask) {
                /* Keys not pressed. Skip conditional block. */
                this->SkipConditionalBlock();
            }
            break;
        case CheatVmOpcodeType_PerformArithmeticRegister: {
            const u64 operand_1_value =
                this->registers[cur_opcode.perform_math_reg.src_reg_1_index];
            const u64 operand_2_value =
                cur_opcode.perform_math_reg.has_immediate
                    ? GetVmInt(cur_opcode.perform_math_reg.value,
                               cur_opcode.perform_math_reg.bit_width)
                    : this->registers[cur_opcode.perform_math_reg.src_reg_2_index];

            u64 res_val = 0;
            /* Do requested math. */
            switch (cur_opcode.perform_math_reg.math_type) {
            case RegisterArithmeticType_Addition:
                res_val = operand_1_value + operand_2_value;
                break;
            case RegisterArithmeticType_Subtraction:
                res_val = operand_1_value - operand_2_value;
                break;
            case RegisterArithmeticType_Multiplication:
                res_val = operand_1_value * operand_2_value;
                break;
            case RegisterArithmeticType_LeftShift:
                res_val = operand_1_value << operand_2_value;
                break;
            case RegisterArithmeticType_RightShift:
                res_val = operand_1_value >> operand_2_value;
                break;
            case RegisterArithmeticType_LogicalAnd:
                res_val = operand_1_value & operand_2_value;
                break;
            case RegisterArithmeticType_LogicalOr:
                res_val = operand_1_value | operand_2_value;
                break;
            case RegisterArithmeticType_LogicalNot:
                res_val = ~operand_1_value;
                break;
            case RegisterArithmeticType_LogicalXor:
                res_val = operand_1_value ^ operand_2_value;
                break;
            case RegisterArithmeticType_None:
                res_val = operand_1_value;
                break;
            }

            /* Apply bit width. */
            switch (cur_opcode.perform_math_reg.bit_width) {
            case 1:
                res_val = static_cast<u8>(res_val);
                break;
            case 2:
                res_val = static_cast<u16>(res_val);
                break;
            case 4:
                res_val = static_cast<u32>(res_val);
                break;
            case 8:
                res_val = static_cast<u64>(res_val);
                break;
            }

            /* Save to register. */
            this->registers[cur_opcode.perform_math_reg.dst_reg_index] = res_val;
        } break;
        case CheatVmOpcodeType_StoreRegisterToAddress: {
            /* Calculate address. */
            u64 dst_value = this->registers[cur_opcode.str_register.str_reg_index];
            u64 dst_address = this->registers[cur_opcode.str_register.addr_reg_index];
            switch (cur_opcode.str_register.ofs_type) {
            case StoreRegisterOffsetType_None:
                /* Nothing more to do */
                break;
            case StoreRegisterOffsetType_Reg:
                dst_address += this->registers[cur_opcode.str_register.ofs_reg_index];
                break;
            case StoreRegisterOffsetType_Imm:
                dst_address += cur_opcode.str_register.rel_address;
                break;
            case StoreRegisterOffsetType_MemReg:
                dst_address =
                    GetCheatProcessAddress(metadata, cur_opcode.str_register.mem_type,
                                           this->registers[cur_opcode.str_register.addr_reg_index]);
                break;
            case StoreRegisterOffsetType_MemImm:
                dst_address = GetCheatProcessAddress(metadata, cur_opcode.str_register.mem_type,
                                                     cur_opcode.str_register.rel_address);
                break;
            case StoreRegisterOffsetType_MemImmReg:
                dst_address =
                    GetCheatProcessAddress(metadata, cur_opcode.str_register.mem_type,
                                           this->registers[cur_opcode.str_register.addr_reg_index] +
                                               cur_opcode.str_register.rel_address);
                break;
            }

            /* Write value to memory. Write only on valid bitwidth. */
            switch (cur_opcode.str_register.bit_width) {
            case 1:
            case 2:
            case 4:
            case 8:
                callbacks->MemoryWrite(dst_address, &dst_value, cur_opcode.str_register.bit_width);
                break;
            }

            /* Increment register if relevant. */
            if (cur_opcode.str_register.increment_reg) {
                this->registers[cur_opcode.str_register.addr_reg_index] +=
                    cur_opcode.str_register.bit_width;
            }
        } break;
        case CheatVmOpcodeType_BeginRegisterConditionalBlock: {
            /* Get value from register. */
            u64 src_value = 0;
            switch (cur_opcode.begin_reg_cond.bit_width) {
            case 1:
                src_value = static_cast<u8>(
                    this->registers[cur_opcode.begin_reg_cond.val_reg_index] & 0xFFul);
                break;
            case 2:
                src_value = static_cast<u16>(
                    this->registers[cur_opcode.begin_reg_cond.val_reg_index] & 0xFFFFul);
                break;
            case 4:
                src_value = static_cast<u32>(
                    this->registers[cur_opcode.begin_reg_cond.val_reg_index] & 0xFFFFFFFFul);
                break;
            case 8:
                src_value =
                    static_cast<u64>(this->registers[cur_opcode.begin_reg_cond.val_reg_index] &
                                     0xFFFFFFFFFFFFFFFFul);
                break;
            }

            /* Read value from memory. */
            u64 cond_value = 0;
            if (cur_opcode.begin_reg_cond.comp_type == CompareRegisterValueType_StaticValue) {
                cond_value =
                    GetVmInt(cur_opcode.begin_reg_cond.value, cur_opcode.begin_reg_cond.bit_width);
            } else if (cur_opcode.begin_reg_cond.comp_type ==
                       CompareRegisterValueType_OtherRegister) {
                switch (cur_opcode.begin_reg_cond.bit_width) {
                case 1:
                    cond_value = static_cast<u8>(
                        this->registers[cur_opcode.begin_reg_cond.other_reg_index] & 0xFFul);
                    break;
                case 2:
                    cond_value = static_cast<u16>(
                        this->registers[cur_opcode.begin_reg_cond.other_reg_index] & 0xFFFFul);
                    break;
                case 4:
                    cond_value = static_cast<u32>(
                        this->registers[cur_opcode.begin_reg_cond.other_reg_index] & 0xFFFFFFFFul);
                    break;
                case 8:
                    cond_value = static_cast<u64>(
                        this->registers[cur_opcode.begin_reg_cond.other_reg_index] &
                        0xFFFFFFFFFFFFFFFFul);
                    break;
                }
            } else {
                u64 cond_address = 0;
                switch (cur_opcode.begin_reg_cond.comp_type) {
                case CompareRegisterValueType_MemoryRelAddr:
                    cond_address =
                        GetCheatProcessAddress(metadata, cur_opcode.begin_reg_cond.mem_type,
                                               cur_opcode.begin_reg_cond.rel_address);
                    break;
                case CompareRegisterValueType_MemoryOfsReg:
                    cond_address = GetCheatProcessAddress(
                        metadata, cur_opcode.begin_reg_cond.mem_type,
                        this->registers[cur_opcode.begin_reg_cond.ofs_reg_index]);
                    break;
                case CompareRegisterValueType_RegisterRelAddr:
                    cond_address = this->registers[cur_opcode.begin_reg_cond.addr_reg_index] +
                                   cur_opcode.begin_reg_cond.rel_address;
                    break;
                case CompareRegisterValueType_RegisterOfsReg:
                    cond_address = this->registers[cur_opcode.begin_reg_cond.addr_reg_index] +
                                   this->registers[cur_opcode.begin_reg_cond.ofs_reg_index];
                    break;
                default:
                    break;
                }
                switch (cur_opcode.begin_reg_cond.bit_width) {
                case 1:
                case 2:
                case 4:
                case 8:
                    callbacks->MemoryRead(cond_address, &cond_value,
                                          cur_opcode.begin_reg_cond.bit_width);
                    break;
                }
            }

            /* Check against condition. */
            bool cond_met = false;
            switch (cur_opcode.begin_reg_cond.cond_type) {
            case ConditionalComparisonType_GT:
                cond_met = src_value > cond_value;
                break;
            case ConditionalComparisonType_GE:
                cond_met = src_value >= cond_value;
                break;
            case ConditionalComparisonType_LT:
                cond_met = src_value < cond_value;
                break;
            case ConditionalComparisonType_LE:
                cond_met = src_value <= cond_value;
                break;
            case ConditionalComparisonType_EQ:
                cond_met = src_value == cond_value;
                break;
            case ConditionalComparisonType_NE:
                cond_met = src_value != cond_value;
                break;
            }

            /* Skip conditional block if condition not met. */
            if (!cond_met) {
                this->SkipConditionalBlock();
            }
        } break;
        case CheatVmOpcodeType_SaveRestoreRegister:
            /* Save or restore a register. */
            switch (cur_opcode.save_restore_reg.op_type) {
            case SaveRestoreRegisterOpType_ClearRegs:
                this->registers[cur_opcode.save_restore_reg.dst_index] = 0ul;
                break;
            case SaveRestoreRegisterOpType_ClearSaved:
                this->saved_values[cur_opcode.save_restore_reg.dst_index] = 0ul;
                break;
            case SaveRestoreRegisterOpType_Save:
                this->saved_values[cur_opcode.save_restore_reg.dst_index] =
                    this->registers[cur_opcode.save_restore_reg.src_index];
                break;
            case SaveRestoreRegisterOpType_Restore:
            default:
                this->registers[cur_opcode.save_restore_reg.dst_index] =
                    this->saved_values[cur_opcode.save_restore_reg.src_index];
                break;
            }
            break;
        case CheatVmOpcodeType_SaveRestoreRegisterMask:
            /* Save or restore register mask. */
            u64* src;
            u64* dst;
            switch (cur_opcode.save_restore_regmask.op_type) {
            case SaveRestoreRegisterOpType_ClearSaved:
            case SaveRestoreRegisterOpType_Save:
                src = this->registers.data();
                dst = this->saved_values.data();
                break;
            case SaveRestoreRegisterOpType_ClearRegs:
            case SaveRestoreRegisterOpType_Restore:
            default:
                src = this->registers.data();
                dst = this->saved_values.data();
                break;
            }
            for (size_t i = 0; i < NumRegisters; i++) {
                if (cur_opcode.save_restore_regmask.should_operate[i]) {
                    switch (cur_opcode.save_restore_regmask.op_type) {
                    case SaveRestoreRegisterOpType_ClearSaved:
                    case SaveRestoreRegisterOpType_ClearRegs:
                        dst[i] = 0ul;
                        break;
                    case SaveRestoreRegisterOpType_Save:
                    case SaveRestoreRegisterOpType_Restore:
                    default:
                        dst[i] = src[i];
                        break;
                    }
                }
            }
            break;
        case CheatVmOpcodeType_DebugLog: {
            /* Read value from memory. */
            u64 log_value = 0;
            if (cur_opcode.debug_log.val_type == DebugLogValueType_RegisterValue) {
                switch (cur_opcode.debug_log.bit_width) {
                case 1:
                    log_value = static_cast<u8>(
                        this->registers[cur_opcode.debug_log.val_reg_index] & 0xFFul);
                    break;
                case 2:
                    log_value = static_cast<u16>(
                        this->registers[cur_opcode.debug_log.val_reg_index] & 0xFFFFul);
                    break;
                case 4:
                    log_value = static_cast<u32>(
                        this->registers[cur_opcode.debug_log.val_reg_index] & 0xFFFFFFFFul);
                    break;
                case 8:
                    log_value = static_cast<u64>(
                        this->registers[cur_opcode.debug_log.val_reg_index] & 0xFFFFFFFFFFFFFFFFul);
                    break;
                }
            } else {
                u64 val_address = 0;
                switch (cur_opcode.debug_log.val_type) {
                case DebugLogValueType_MemoryRelAddr:
                    val_address = GetCheatProcessAddress(metadata, cur_opcode.debug_log.mem_type,
                                                         cur_opcode.debug_log.rel_address);
                    break;
                case DebugLogValueType_MemoryOfsReg:
                    val_address =
                        GetCheatProcessAddress(metadata, cur_opcode.debug_log.mem_type,
                                               this->registers[cur_opcode.debug_log.ofs_reg_index]);
                    break;
                case DebugLogValueType_RegisterRelAddr:
                    val_address = this->registers[cur_opcode.debug_log.addr_reg_index] +
                                  cur_opcode.debug_log.rel_address;
                    break;
                case DebugLogValueType_RegisterOfsReg:
                    val_address = this->registers[cur_opcode.debug_log.addr_reg_index] +
                                  this->registers[cur_opcode.debug_log.ofs_reg_index];
                    break;
                default:
                    break;
                }
                switch (cur_opcode.debug_log.bit_width) {
                case 1:
                case 2:
                case 4:
                case 8:
                    callbacks->MemoryRead(val_address, &log_value, cur_opcode.debug_log.bit_width);
                    break;
                }
            }

            /* Log value. */
            this->DebugLog(cur_opcode.debug_log.log_id, log_value);
        } break;
        default:
            /* By default, we do a no-op. */
            break;
        }
    }
}

} // namespace Memory