Pica: Add command processor.

src/video_core/command_processor.cpp

@@ -0,0 +1,60 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#include "pica.h"
+#include "command_processor.h"
+
+
+namespace Pica {
+
+Regs registers;
+
+namespace CommandProcessor {
+
+static inline void WritePicaReg(u32 id, u32 value) {
+    u32 old_value = registers[id];
+    registers[id] = value;
+
+    switch(id) {
+        // TODO: Perform actions for anything which requires special treatment here...
+
+        default:
+            break;
+    }
+}
+
+static std::ptrdiff_t ExecuteCommandBlock(const u32* first_command_word) {
+    const CommandHeader& header = *(const CommandHeader*)(&first_command_word[1]);
+
+    u32* read_pointer = (u32*)first_command_word;
+
+    // TODO: Take parameter mask into consideration!
+
+    WritePicaReg(header.cmd_id, *read_pointer);
+    read_pointer += 2;
+
+    for (int i = 1; i < 1+header.extra_data_length; ++i) {
+        u32 cmd = header.cmd_id + ((header.group_commands) ? i : 0);
+        WritePicaReg(cmd, *read_pointer);
+        ++read_pointer;
+    }
+
+    // align read pointer to 8 bytes
+    if ((first_command_word - read_pointer) % 2)
+        ++read_pointer;
+
+    return read_pointer - first_command_word;
+}
+
+void ProcessCommandList(const u32* list, u32 size) {
+    u32* read_pointer = (u32*)list;
+
+    while (read_pointer < list + size) {
+        read_pointer += ExecuteCommandBlock(read_pointer);
+    }
+}
+
+} // namespace
+
+} // namespace