From 9be4bf9aa585c68a6282cbd1a46bc874a5b2d018 Mon Sep 17 00:00:00 2001
From: Zephyron <zephyron@citron-emu.org>
Date: Sat, 4 Jan 2025 18:57:12 +1000
Subject: [PATCH] nvdrv: Implement ZBCSetTable functionality

Implements basic Zero Bandwidth Clear (ZBC) table support in nvhost_ctrl_gpu.
This adds storage and validation for both color and depth clear values,
replacing the previous stub implementation. ZBC is a hardware optimization
technique used by NVIDIA GPUs to efficiently handle buffer clearing operations.

Changes include:
- Added ZBC table storage structures
- Implemented parameter validation
- Added separate handling for color and depth modes
- Improved debug logging
- Added documentation explaining ZBC functionality
---
 .../service/nvdrv/devices/nvhost_ctrl_gpu.cpp | 26 +++++++++++++++++--
 .../service/nvdrv/devices/nvhost_ctrl_gpu.h   | 20 ++++++++++++++
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.cpp b/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.cpp
index b7a5c7089..189b15655 100644
--- a/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.cpp
+++ b/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.cpp
@@ -223,8 +223,30 @@ NvResult nvhost_ctrl_gpu::ZCullGetInfo(IoctlNvgpuGpuZcullGetInfoArgs& params) {
 }
 
 NvResult nvhost_ctrl_gpu::ZBCSetTable(IoctlZbcSetTable& params) {
-    LOG_WARNING(Service_NVDRV, "(STUBBED) called");
-    // TODO(ogniK): What does this even actually do?
+    LOG_DEBUG(Service_NVDRV, "called with index={}, format={}, mode={}",
+              params.color_ds_table_index, params.format, params.mode);
+
+    // Validate parameters
+    if (params.color_ds_table_index >= MaxZBCTableSize || params.format >= MaxZBCFormats) {
+        return NvResult::InvalidArgument;
+    }
+
+    // Store the color/depth values
+    switch (params.mode) {
+    case ZBCTableMode::COLOR:
+        // Store color values
+        std::memcpy(zbc_color_table[params.color_ds_table_index].color_ds,
+                    params.color_ds, sizeof(params.color_ds));
+        break;
+    case ZBCTableMode::DEPTH:
+        // Store depth values
+        std::memcpy(zbc_depth_table[params.color_ds_table_index].depth,
+                    params.depth, sizeof(params.depth));
+        break;
+    default:
+        return NvResult::InvalidArgument;
+    }
+
     return NvResult::Success;
 }
 
diff --git a/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.h b/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.h
index 100b612da..2009de8c5 100644
--- a/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.h
+++ b/src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.h
@@ -4,6 +4,7 @@
 #pragma once
 
 #include <vector>
+#include <array>
 
 #include "common/common_funcs.h"
 #include "common/common_types.h"
@@ -34,6 +35,25 @@ public:
     Kernel::KEvent* QueryEvent(u32 event_id) override;
 
 private:
+    static constexpr std::size_t MaxZBCTableSize = 16;
+    static constexpr std::size_t MaxZBCFormats = 32;
+
+    enum class ZBCTableMode : u32 {
+        COLOR = 0,
+        DEPTH = 1,
+    };
+
+    struct ZBCColorEntry {
+        u32 color_ds[4];
+    };
+
+    struct ZBCDepthEntry {
+        u32 depth[4];
+    };
+
+    std::array<ZBCColorEntry, MaxZBCTableSize> zbc_color_table{};
+    std::array<ZBCDepthEntry, MaxZBCTableSize> zbc_depth_table{};
+
     struct IoctlGpuCharacteristics {
         u32_le arch;                       // 0x120 (NVGPU_GPU_ARCH_GM200)
         u32_le impl;                       // 0xB (NVGPU_GPU_IMPL_GM20B)