yuzu/src/video_core/engines/maxwell_3d.cpp

// Copyright 2018 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#include <cstring>
#include <optional>
#include "common/assert.h"
#include "core/core.h"
#include "core/core_timing.h"
#include "video_core/dirty_flags.h"
#include "video_core/engines/maxwell_3d.h"
#include "video_core/gpu.h"
#include "video_core/memory_manager.h"
#include "video_core/rasterizer_interface.h"
#include "video_core/textures/texture.h"

namespace Tegra::Engines {

using VideoCore::QueryType;

/// First register id that is actually a Macro call.
constexpr u32 MacroRegistersStart = 0xE00;

Maxwell3D::Maxwell3D(Core::System& system_, MemoryManager& memory_manager_)
    : system{system_}, memory_manager{memory_manager_}, macro_engine{GetMacroEngine(*this)},
      upload_state{memory_manager, regs.upload} {
    dirty.flags.flip();
    InitializeRegisterDefaults();
}

Maxwell3D::~Maxwell3D() = default;

void Maxwell3D::BindRasterizer(VideoCore::RasterizerInterface* rasterizer_) {
    rasterizer = rasterizer_;
    upload_state.BindRasterizer(rasterizer_);
}

void Maxwell3D::InitializeRegisterDefaults() {
    // Initializes registers to their default values - what games expect them to be at boot. This is
    // for certain registers that may not be explicitly set by games.

    // Reset all registers to zero
    std::memset(&regs, 0, sizeof(regs));

    // Depth range near/far is not always set, but is expected to be the default 0.0f, 1.0f. This is
    // needed for ARMS.
    for (auto& viewport : regs.viewports) {
        viewport.depth_range_near = 0.0f;
        viewport.depth_range_far = 1.0f;
    }
    for (auto& viewport : regs.viewport_transform) {
        viewport.swizzle.x.Assign(Regs::ViewportSwizzle::PositiveX);
        viewport.swizzle.y.Assign(Regs::ViewportSwizzle::PositiveY);
        viewport.swizzle.z.Assign(Regs::ViewportSwizzle::PositiveZ);
        viewport.swizzle.w.Assign(Regs::ViewportSwizzle::PositiveW);
    }

    // Doom and Bomberman seems to use the uninitialized registers and just enable blend
    // so initialize blend registers with sane values
    regs.blend.equation_rgb = Regs::Blend::Equation::Add;
    regs.blend.factor_source_rgb = Regs::Blend::Factor::One;
    regs.blend.factor_dest_rgb = Regs::Blend::Factor::Zero;
    regs.blend.equation_a = Regs::Blend::Equation::Add;
    regs.blend.factor_source_a = Regs::Blend::Factor::One;
    regs.blend.factor_dest_a = Regs::Blend::Factor::Zero;
    for (auto& blend : regs.independent_blend) {
        blend.equation_rgb = Regs::Blend::Equation::Add;
        blend.factor_source_rgb = Regs::Blend::Factor::One;
        blend.factor_dest_rgb = Regs::Blend::Factor::Zero;
        blend.equation_a = Regs::Blend::Equation::Add;
        blend.factor_source_a = Regs::Blend::Factor::One;
        blend.factor_dest_a = Regs::Blend::Factor::Zero;
    }
    regs.stencil_front_op_fail = Regs::StencilOp::Keep;
    regs.stencil_front_op_zfail = Regs::StencilOp::Keep;
    regs.stencil_front_op_zpass = Regs::StencilOp::Keep;
    regs.stencil_front_func_func = Regs::ComparisonOp::Always;
    regs.stencil_front_func_mask = 0xFFFFFFFF;
    regs.stencil_front_mask = 0xFFFFFFFF;
    regs.stencil_two_side_enable = 1;
    regs.stencil_back_op_fail = Regs::StencilOp::Keep;
    regs.stencil_back_op_zfail = Regs::StencilOp::Keep;
    regs.stencil_back_op_zpass = Regs::StencilOp::Keep;
    regs.stencil_back_func_func = Regs::ComparisonOp::Always;
    regs.stencil_back_func_mask = 0xFFFFFFFF;
    regs.stencil_back_mask = 0xFFFFFFFF;

    regs.depth_test_func = Regs::ComparisonOp::Always;
    regs.front_face = Regs::FrontFace::CounterClockWise;
    regs.cull_face = Regs::CullFace::Back;

    // TODO(Rodrigo): Most games do not set a point size. I think this is a case of a
    // register carrying a default value. Assume it's OpenGL's default (1).
    regs.point_size = 1.0f;

    // TODO(bunnei): Some games do not initialize the color masks (e.g. Sonic Mania). Assuming a
    // default of enabled fixes rendering here.
    for (auto& color_mask : regs.color_mask) {
        color_mask.R.Assign(1);
        color_mask.G.Assign(1);
        color_mask.B.Assign(1);
        color_mask.A.Assign(1);
    }

    for (auto& format : regs.vertex_attrib_format) {
        format.constant.Assign(1);
    }

    // NVN games expect these values to be enabled at boot
    regs.rasterize_enable = 1;
    regs.rt_separate_frag_data = 1;
    regs.framebuffer_srgb = 1;
    regs.line_width_aliased = 1.0f;
    regs.line_width_smooth = 1.0f;
    regs.front_face = Maxwell3D::Regs::FrontFace::ClockWise;
    regs.polygon_mode_back = Maxwell3D::Regs::PolygonMode::Fill;
    regs.polygon_mode_front = Maxwell3D::Regs::PolygonMode::Fill;

    shadow_state = regs;

    mme_inline[MAXWELL3D_REG_INDEX(draw.vertex_end_gl)] = true;
    mme_inline[MAXWELL3D_REG_INDEX(draw.vertex_begin_gl)] = true;
    mme_inline[MAXWELL3D_REG_INDEX(vertex_buffer.count)] = true;
    mme_inline[MAXWELL3D_REG_INDEX(index_array.count)] = true;
}

void Maxwell3D::ProcessMacro(u32 method, const u32* base_start, u32 amount, bool is_last_call) {
    if (executing_macro == 0) {
        // A macro call must begin by writing the macro method's register, not its argument.
        ASSERT_MSG((method % 2) == 0,
                   "Can't start macro execution by writing to the ARGS register");
        executing_macro = method;
    }

    macro_params.insert(macro_params.end(), base_start, base_start + amount);

    // Call the macro when there are no more parameters in the command buffer
    if (is_last_call) {
        CallMacroMethod(executing_macro, macro_params);
        macro_params.clear();
    }
}

u32 Maxwell3D::ProcessShadowRam(u32 method, u32 argument) {
    // Keep track of the register value in shadow_state when requested.
    const auto control = shadow_state.shadow_ram_control;
    if (control == Regs::ShadowRamControl::Track ||
        control == Regs::ShadowRamControl::TrackWithFilter) {
        shadow_state.reg_array[method] = argument;
        return argument;
    }
    if (control == Regs::ShadowRamControl::Replay) {
        return shadow_state.reg_array[method];
    }
    return argument;
}

void Maxwell3D::ProcessDirtyRegisters(u32 method, u32 argument) {
    if (regs.reg_array[method] == argument) {
        return;
    }
    regs.reg_array[method] = argument;

    for (const auto& table : dirty.tables) {
        dirty.flags[table[method]] = true;
    }
}

void Maxwell3D::ProcessMethodCall(u32 method, u32 argument, u32 nonshadow_argument,
                                  bool is_last_call) {
    switch (method) {
    case MAXWELL3D_REG_INDEX(wait_for_idle):
        return rasterizer->WaitForIdle();
    case MAXWELL3D_REG_INDEX(shadow_ram_control):
        shadow_state.shadow_ram_control = static_cast<Regs::ShadowRamControl>(nonshadow_argument);
        return;
    case MAXWELL3D_REG_INDEX(macros.data):
        return macro_engine->AddCode(regs.macros.upload_address, argument);
    case MAXWELL3D_REG_INDEX(macros.bind):
        return ProcessMacroBind(argument);
    case MAXWELL3D_REG_INDEX(firmware[4]):
        return ProcessFirmwareCall4();
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data):
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 1:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 2:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 3:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 4:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 5:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 6:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 7:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 8:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 9:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 10:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 11:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 12:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 13:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 14:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 15:
        return ProcessCBData(argument);
    case MAXWELL3D_REG_INDEX(cb_bind[0]):
        return ProcessCBBind(0);
    case MAXWELL3D_REG_INDEX(cb_bind[1]):
        return ProcessCBBind(1);
    case MAXWELL3D_REG_INDEX(cb_bind[2]):
        return ProcessCBBind(2);
    case MAXWELL3D_REG_INDEX(cb_bind[3]):
        return ProcessCBBind(3);
    case MAXWELL3D_REG_INDEX(cb_bind[4]):
        return ProcessCBBind(4);
    case MAXWELL3D_REG_INDEX(draw.vertex_end_gl):
        return DrawArrays();
    case MAXWELL3D_REG_INDEX(small_index):
        regs.index_array.count = regs.small_index.count;
        regs.index_array.first = regs.small_index.first;
        dirty.flags[VideoCommon::Dirty::IndexBuffer] = true;
        return DrawArrays();
    case MAXWELL3D_REG_INDEX(topology_override):
        use_topology_override = true;
        return;
    case MAXWELL3D_REG_INDEX(clear_buffers):
        return ProcessClearBuffers();
    case MAXWELL3D_REG_INDEX(query.query_get):
        return ProcessQueryGet();
    case MAXWELL3D_REG_INDEX(condition.mode):
        return ProcessQueryCondition();
    case MAXWELL3D_REG_INDEX(counter_reset):
        return ProcessCounterReset();
    case MAXWELL3D_REG_INDEX(sync_info):
        return ProcessSyncPoint();
    case MAXWELL3D_REG_INDEX(exec_upload):
        return upload_state.ProcessExec(regs.exec_upload.linear != 0);
    case MAXWELL3D_REG_INDEX(data_upload):
        upload_state.ProcessData(argument, is_last_call);
        if (is_last_call) {
        }
        return;
    case MAXWELL3D_REG_INDEX(fragment_barrier):
        return rasterizer->FragmentBarrier();
    case MAXWELL3D_REG_INDEX(tiled_cache_barrier):
        return rasterizer->TiledCacheBarrier();
    }
}

void Maxwell3D::CallMacroMethod(u32 method, const std::vector<u32>& parameters) {
    // Reset the current macro.
    executing_macro = 0;

    // Lookup the macro offset
    const u32 entry =
        ((method - MacroRegistersStart) >> 1) % static_cast<u32>(macro_positions.size());

    // Execute the current macro.
    macro_engine->Execute(macro_positions[entry], parameters);
    if (mme_draw.current_mode != MMEDrawMode::Undefined) {
        FlushMMEInlineDraw();
    }
}

void Maxwell3D::CallMethod(u32 method, u32 method_argument, bool is_last_call) {
    // It is an error to write to a register other than the current macro's ARG register before it
    // has finished execution.
    if (executing_macro != 0) {
        ASSERT(method == executing_macro + 1);
    }

    // Methods after 0xE00 are special, they're actually triggers for some microcode that was
    // uploaded to the GPU during initialization.
    if (method >= MacroRegistersStart) {
        ProcessMacro(method, &method_argument, 1, is_last_call);
        return;
    }

    ASSERT_MSG(method < Regs::NUM_REGS,
               "Invalid Maxwell3D register, increase the size of the Regs structure");

    const u32 argument = ProcessShadowRam(method, method_argument);
    ProcessDirtyRegisters(method, argument);
    ProcessMethodCall(method, argument, method_argument, is_last_call);
}

void Maxwell3D::CallMultiMethod(u32 method, const u32* base_start, u32 amount,
                                u32 methods_pending) {
    // Methods after 0xE00 are special, they're actually triggers for some microcode that was
    // uploaded to the GPU during initialization.
    if (method >= MacroRegistersStart) {
        ProcessMacro(method, base_start, amount, amount == methods_pending);
        return;
    }
    switch (method) {
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data):
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 1:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 2:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 3:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 4:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 5:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 6:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 7:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 8:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 9:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 10:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 11:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 12:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 13:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 14:
    case MAXWELL3D_REG_INDEX(const_buffer.cb_data) + 15:
        ProcessCBMultiData(base_start, amount);
        break;
    default:
        for (std::size_t i = 0; i < amount; i++) {
            CallMethod(method, base_start[i], methods_pending - static_cast<u32>(i) <= 1);
        }
        break;
    }
}

void Maxwell3D::StepInstance(const MMEDrawMode expected_mode, const u32 count) {
    if (mme_draw.current_mode == MMEDrawMode::Undefined) {
        if (mme_draw.gl_begin_consume) {
            mme_draw.current_mode = expected_mode;
            mme_draw.current_count = count;
            mme_draw.instance_count = 1;
            mme_draw.gl_begin_consume = false;
            mme_draw.gl_end_count = 0;
        }
        return;
    } else {
        if (mme_draw.current_mode == expected_mode && count == mme_draw.current_count &&
            mme_draw.instance_mode && mme_draw.gl_begin_consume) {
            mme_draw.instance_count++;
            mme_draw.gl_begin_consume = false;
            return;
        } else {
            FlushMMEInlineDraw();
        }
    }
    // Tail call in case it needs to retry.
    StepInstance(expected_mode, count);
}

void Maxwell3D::CallMethodFromMME(u32 method, u32 method_argument) {
    if (mme_inline[method]) {
        regs.reg_array[method] = method_argument;
        if (method == MAXWELL3D_REG_INDEX(vertex_buffer.count) ||
            method == MAXWELL3D_REG_INDEX(index_array.count)) {
            const MMEDrawMode expected_mode = method == MAXWELL3D_REG_INDEX(vertex_buffer.count)
                                                  ? MMEDrawMode::Array
                                                  : MMEDrawMode::Indexed;
            StepInstance(expected_mode, method_argument);
        } else if (method == MAXWELL3D_REG_INDEX(draw.vertex_begin_gl)) {
            mme_draw.instance_mode =
                (regs.draw.instance_next != 0) || (regs.draw.instance_cont != 0);
            mme_draw.gl_begin_consume = true;
        } else {
            mme_draw.gl_end_count++;
        }
    } else {
        if (mme_draw.current_mode != MMEDrawMode::Undefined) {
            FlushMMEInlineDraw();
        }
        CallMethod(method, method_argument, true);
    }
}

void Maxwell3D::ProcessTopologyOverride() {
    using PrimitiveTopology = Maxwell3D::Regs::PrimitiveTopology;
    using PrimitiveTopologyOverride = Maxwell3D::Regs::PrimitiveTopologyOverride;

    PrimitiveTopology topology{};

    switch (regs.topology_override) {
    case PrimitiveTopologyOverride::None:
        topology = regs.draw.topology;
        break;
    case PrimitiveTopologyOverride::Points:
        topology = PrimitiveTopology::Points;
        break;
    case PrimitiveTopologyOverride::Lines:
        topology = PrimitiveTopology::Lines;
        break;
    case PrimitiveTopologyOverride::LineStrip:
        topology = PrimitiveTopology::LineStrip;
        break;
    default:
        topology = static_cast<PrimitiveTopology>(regs.topology_override);
        break;
    }

    if (use_topology_override) {
        regs.draw.topology.Assign(topology);
    }
}

void Maxwell3D::FlushMMEInlineDraw() {
    LOG_TRACE(HW_GPU, "called, topology={}, count={}", regs.draw.topology.Value(),
              regs.vertex_buffer.count);
    ASSERT_MSG(!(regs.index_array.count && regs.vertex_buffer.count), "Both indexed and direct?");
    ASSERT(mme_draw.instance_count == mme_draw.gl_end_count);

    // Both instance configuration registers can not be set at the same time.
    ASSERT_MSG(!regs.draw.instance_next || !regs.draw.instance_cont,
               "Illegal combination of instancing parameters");

    ProcessTopologyOverride();

    const bool is_indexed = mme_draw.current_mode == MMEDrawMode::Indexed;
    if (ShouldExecute()) {
        rasterizer->Draw(is_indexed, true);
    }

    // TODO(bunnei): Below, we reset vertex count so that we can use these registers to determine if
    // the game is trying to draw indexed or direct mode. This needs to be verified on HW still -
    // it's possible that it is incorrect and that there is some other register used to specify the
    // drawing mode.
    if (is_indexed) {
        regs.index_array.count = 0;
    } else {
        regs.vertex_buffer.count = 0;
    }
    mme_draw.current_mode = MMEDrawMode::Undefined;
    mme_draw.current_count = 0;
    mme_draw.instance_count = 0;
    mme_draw.instance_mode = false;
    mme_draw.gl_begin_consume = false;
    mme_draw.gl_end_count = 0;
}

void Maxwell3D::ProcessMacroUpload(u32 data) {
    macro_engine->AddCode(regs.macros.upload_address++, data);
}

void Maxwell3D::ProcessMacroBind(u32 data) {
    macro_positions[regs.macros.entry++] = data;
}

void Maxwell3D::ProcessFirmwareCall4() {
    LOG_WARNING(HW_GPU, "(STUBBED) called");

    // Firmware call 4 is a blob that changes some registers depending on its parameters.
    // These registers don't affect emulation and so are stubbed by setting 0xd00 to 1.
    regs.reg_array[0xd00] = 1;
}

void Maxwell3D::StampQueryResult(u64 payload, bool long_query) {
    struct LongQueryResult {
        u64_le value;
        u64_le timestamp;
    };
    static_assert(sizeof(LongQueryResult) == 16, "LongQueryResult has wrong size");
    const GPUVAddr sequence_address{regs.query.QueryAddress()};
    if (long_query) {
        // Write the 128-bit result structure in long mode. Note: We emulate an infinitely fast
        // GPU, this command may actually take a while to complete in real hardware due to GPU
        // wait queues.
        LongQueryResult query_result{payload, system.GPU().GetTicks()};
        memory_manager.WriteBlock(sequence_address, &query_result, sizeof(query_result));
    } else {
        memory_manager.Write<u32>(sequence_address, static_cast<u32>(payload));
    }
}

void Maxwell3D::ProcessQueryGet() {
    // TODO(Subv): Support the other query units.
    if (regs.query.query_get.unit != Regs::QueryUnit::Crop) {
        LOG_DEBUG(HW_GPU, "Units other than CROP are unimplemented");
    }

    switch (regs.query.query_get.operation) {
    case Regs::QueryOperation::Release:
        if (regs.query.query_get.fence == 1) {
            rasterizer->SignalSemaphore(regs.query.QueryAddress(), regs.query.query_sequence);
        } else {
            StampQueryResult(regs.query.query_sequence, regs.query.query_get.short_query == 0);
        }
        break;
    case Regs::QueryOperation::Acquire:
        // TODO(Blinkhawk): Under this operation, the GPU waits for the CPU to write a value that
        // matches the current payload.
        UNIMPLEMENTED_MSG("Unimplemented query operation ACQUIRE");
        break;
    case Regs::QueryOperation::Counter:
        if (const std::optional<u64> result = GetQueryResult()) {
            // If the query returns an empty optional it means it's cached and deferred.
            // In this case we have a non-empty result, so we stamp it immediately.
            StampQueryResult(*result, regs.query.query_get.short_query == 0);
        }
        break;
    case Regs::QueryOperation::Trap:
        UNIMPLEMENTED_MSG("Unimplemented query operation TRAP");
        break;
    default:
        UNIMPLEMENTED_MSG("Unknown query operation");
        break;
    }
}

void Maxwell3D::ProcessQueryCondition() {
    const GPUVAddr condition_address{regs.condition.Address()};
    switch (regs.condition.mode) {
    case Regs::ConditionMode::Always: {
        execute_on = true;
        break;
    }
    case Regs::ConditionMode::Never: {
        execute_on = false;
        break;
    }
    case Regs::ConditionMode::ResNonZero: {
        Regs::QueryCompare cmp;
        memory_manager.ReadBlock(condition_address, &cmp, sizeof(cmp));
        execute_on = cmp.initial_sequence != 0U && cmp.initial_mode != 0U;
        break;
    }
    case Regs::ConditionMode::Equal: {
        Regs::QueryCompare cmp;
        memory_manager.ReadBlock(condition_address, &cmp, sizeof(cmp));
        execute_on =
            cmp.initial_sequence == cmp.current_sequence && cmp.initial_mode == cmp.current_mode;
        break;
    }
    case Regs::ConditionMode::NotEqual: {
        Regs::QueryCompare cmp;
        memory_manager.ReadBlock(condition_address, &cmp, sizeof(cmp));
        execute_on =
            cmp.initial_sequence != cmp.current_sequence || cmp.initial_mode != cmp.current_mode;
        break;
    }
    default: {
        UNIMPLEMENTED_MSG("Uninplemented Condition Mode!");
        execute_on = true;
        break;
    }
    }
}

void Maxwell3D::ProcessCounterReset() {
    switch (regs.counter_reset) {
    case Regs::CounterReset::SampleCnt:
        rasterizer->ResetCounter(QueryType::SamplesPassed);
        break;
    default:
        LOG_DEBUG(Render_OpenGL, "Unimplemented counter reset={}", regs.counter_reset);
        break;
    }
}

void Maxwell3D::ProcessSyncPoint() {
    const u32 sync_point = regs.sync_info.sync_point.Value();
    const u32 increment = regs.sync_info.increment.Value();
    [[maybe_unused]] const u32 cache_flush = regs.sync_info.unknown.Value();
    if (increment) {
        rasterizer->SignalSyncPoint(sync_point);
    }
}

void Maxwell3D::DrawArrays() {
    LOG_TRACE(HW_GPU, "called, topology={}, count={}", regs.draw.topology.Value(),
              regs.vertex_buffer.count);
    ASSERT_MSG(!(regs.index_array.count && regs.vertex_buffer.count), "Both indexed and direct?");

    // Both instance configuration registers can not be set at the same time.
    ASSERT_MSG(!regs.draw.instance_next || !regs.draw.instance_cont,
               "Illegal combination of instancing parameters");

    ProcessTopologyOverride();

    if (regs.draw.instance_next) {
        // Increment the current instance *before* drawing.
        state.current_instance += 1;
    } else if (!regs.draw.instance_cont) {
        // Reset the current instance to 0.
        state.current_instance = 0;
    }

    const bool is_indexed{regs.index_array.count && !regs.vertex_buffer.count};
    if (ShouldExecute()) {
        rasterizer->Draw(is_indexed, false);
    }

    // TODO(bunnei): Below, we reset vertex count so that we can use these registers to determine if
    // the game is trying to draw indexed or direct mode. This needs to be verified on HW still -
    // it's possible that it is incorrect and that there is some other register used to specify the
    // drawing mode.
    if (is_indexed) {
        regs.index_array.count = 0;
    } else {
        regs.vertex_buffer.count = 0;
    }
}

std::optional<u64> Maxwell3D::GetQueryResult() {
    switch (regs.query.query_get.select) {
    case Regs::QuerySelect::Zero:
        return 0;
    case Regs::QuerySelect::SamplesPassed:
        // Deferred.
        rasterizer->Query(regs.query.QueryAddress(), QueryType::SamplesPassed,
                          system.GPU().GetTicks());
        return std::nullopt;
    default:
        LOG_DEBUG(HW_GPU, "Unimplemented query select type {}",
                  regs.query.query_get.select.Value());
        return 1;
    }
}

void Maxwell3D::ProcessCBBind(size_t stage_index) {
    // Bind the buffer currently in CB_ADDRESS to the specified index in the desired shader stage.
    const auto& bind_data = regs.cb_bind[stage_index];
    auto& buffer = state.shader_stages[stage_index].const_buffers[bind_data.index];
    buffer.enabled = bind_data.valid.Value() != 0;
    buffer.address = regs.const_buffer.BufferAddress();
    buffer.size = regs.const_buffer.cb_size;

    const bool is_enabled = bind_data.valid.Value() != 0;
    if (!is_enabled) {
        rasterizer->DisableGraphicsUniformBuffer(stage_index, bind_data.index);
        return;
    }
    const GPUVAddr gpu_addr = regs.const_buffer.BufferAddress();
    const u32 size = regs.const_buffer.cb_size;
    rasterizer->BindGraphicsUniformBuffer(stage_index, bind_data.index, gpu_addr, size);
}

void Maxwell3D::ProcessCBMultiData(const u32* start_base, u32 amount) {
    // Write the input value to the current const buffer at the current position.
    const GPUVAddr buffer_address = regs.const_buffer.BufferAddress();
    ASSERT(buffer_address != 0);

    // Don't allow writing past the end of the buffer.
    ASSERT(regs.const_buffer.cb_pos <= regs.const_buffer.cb_size);

    const GPUVAddr address{buffer_address + regs.const_buffer.cb_pos};
    const size_t copy_size = amount * sizeof(u32);
    memory_manager.WriteBlock(address, start_base, copy_size);

    // Increment the current buffer position.
    regs.const_buffer.cb_pos += static_cast<u32>(copy_size);
}

void Maxwell3D::ProcessCBData(u32 value) {
    ProcessCBMultiData(&value, 1);
}

Texture::TICEntry Maxwell3D::GetTICEntry(u32 tic_index) const {
    const GPUVAddr tic_address_gpu{regs.tic.Address() + tic_index * sizeof(Texture::TICEntry)};

    Texture::TICEntry tic_entry;
    memory_manager.ReadBlockUnsafe(tic_address_gpu, &tic_entry, sizeof(Texture::TICEntry));

    return tic_entry;
}

Texture::TSCEntry Maxwell3D::GetTSCEntry(u32 tsc_index) const {
    const GPUVAddr tsc_address_gpu{regs.tsc.Address() + tsc_index * sizeof(Texture::TSCEntry)};

    Texture::TSCEntry tsc_entry;
    memory_manager.ReadBlockUnsafe(tsc_address_gpu, &tsc_entry, sizeof(Texture::TSCEntry));
    return tsc_entry;
}

u32 Maxwell3D::GetRegisterValue(u32 method) const {
    ASSERT_MSG(method < Regs::NUM_REGS, "Invalid Maxwell3D register");
    return regs.reg_array[method];
}

void Maxwell3D::ProcessClearBuffers() {
    rasterizer->Clear();
}

} // namespace Tegra::Engines