From 7b6868e908319b91785712410b481e9112621175 Mon Sep 17 00:00:00 2001
From: Subv <subv2112@gmail.com>
Date: Sun, 18 Mar 2018 15:22:06 -0500
Subject: GPU: Implement the BindStorageBuffer macro method in HLE.

This macro binds the SSBO Info Buffer as the current ConstBuffer.
This buffer is usually bound to c0 during shader execution.
Games seem to use this macro instead of directly writing the address for some reason.
---
 src/video_core/engines/maxwell_3d.cpp | 21 +++++++++++++++++++++
 src/video_core/engines/maxwell_3d.h   | 16 +++++++++++++++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/src/video_core/engines/maxwell_3d.cpp b/src/video_core/engines/maxwell_3d.cpp
index 9985e0d50..3a4e88e4e 100644
--- a/src/video_core/engines/maxwell_3d.cpp
+++ b/src/video_core/engines/maxwell_3d.cpp
@@ -13,6 +13,7 @@ constexpr u32 MacroRegistersStart = 0xE00;
 
 const std::unordered_map<u32, Maxwell3D::MethodInfo> Maxwell3D::method_handlers = {
     {0xE24, {"SetShader", 5, &Maxwell3D::SetShader}},
+    {0xE2A, {"BindStorageBuffer", 1, &Maxwell3D::BindStorageBuffer}},
 };
 
 Maxwell3D::Maxwell3D(MemoryManager& memory_manager) : memory_manager(memory_manager) {}
@@ -200,6 +201,26 @@ void Maxwell3D::SetShader(const std::vector<u32>& parameters) {
     ProcessCBBind(shader_stage);
 }
 
+void Maxwell3D::BindStorageBuffer(const std::vector<u32>& parameters) {
+    /**
+     * Parameters description:
+     * [0] = Buffer offset >> 2
+     */
+
+    u32 buffer_offset = parameters[0] << 2;
+
+    // Perform the same operations as the real macro code.
+    // Note: This value is hardcoded in the macro's code.
+    static constexpr u32 DefaultCBSize = 0x5F00;
+    regs.const_buffer.cb_size = DefaultCBSize;
+
+    GPUVAddr address = regs.ssbo_info.BufferAddress();
+    regs.const_buffer.cb_address_high = address >> 32;
+    regs.const_buffer.cb_address_low = address & 0xFFFFFFFF;
+
+    regs.const_buffer.cb_pos = buffer_offset;
+}
+
 void Maxwell3D::ProcessCBBind(Regs::ShaderStage stage) {
     // Bind the buffer currently in CB_ADDRESS to the specified index in the desired shader stage.
     auto& shader = state.shader_stages[static_cast<size_t>(stage)];
diff --git a/src/video_core/engines/maxwell_3d.h b/src/video_core/engines/maxwell_3d.h
index 93b42b53c..3e97d9045 100644
--- a/src/video_core/engines/maxwell_3d.h
+++ b/src/video_core/engines/maxwell_3d.h
@@ -166,7 +166,19 @@ public:
 
                 u32 tex_cb_index;
 
-                INSERT_PADDING_WORDS(0x4B3);
+                INSERT_PADDING_WORDS(0x395);
+
+                struct {
+                    /// Compressed address of a buffer that holds information about bound SSBOs.
+                    /// This address is usually bound to c0 in the shaders.
+                    u32 buffer_address;
+
+                    GPUVAddr BufferAddress() const {
+                        return static_cast<GPUVAddr>(buffer_address) << 8;
+                    }
+                } ssbo_info;
+
+                INSERT_PADDING_WORDS(0x11D);
             };
             std::array<u32, NUM_REGS> reg_array;
         };
@@ -229,6 +241,7 @@ private:
 
     /// Method call handlers
     void SetShader(const std::vector<u32>& parameters);
+    void BindStorageBuffer(const std::vector<u32>& parameters);
 
     struct MethodInfo {
         const char* name;
@@ -252,6 +265,7 @@ ASSERT_REG_POSITION(shader_config[0], 0x800);
 ASSERT_REG_POSITION(const_buffer, 0x8E0);
 ASSERT_REG_POSITION(cb_bind[0], 0x904);
 ASSERT_REG_POSITION(tex_cb_index, 0x982);
+ASSERT_REG_POSITION(ssbo_info, 0xD18);
 
 #undef ASSERT_REG_POSITION
 
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