diff --git a/docs/gpu.md b/docs/gpu.md index 407fcc714..f8e572180 100644 --- a/docs/gpu.md +++ b/docs/gpu.md @@ -1,17 +1,37 @@ # GPU Documentation +## The Xenos Chip + +The [Xenos](https://en.wikipedia.org/wiki/Xenos_\(graphics_chip\)) is a graphics +chip designed by AMD based off of the R5xx architecture. + +### Command Processing + +The Xenos runs commands supplied to it directly by the DirectX bare-bones driver +via a ringbuffer located in system memory. + +The bulk of the command processing code is located at +[src/xenia/gpu/command_processor.cc](../src/xenia/gpu/command_processor.cc) + +### EDRAM + +The Xenos uses special high-speed memory located on the same die as the chip to +store framebuffers/render targets. + +TODO: More documentation + ## Options ### General -See the top of [src/xenia/gpu/gpu.cc](https://github.com/benvanik/xenia/blob/master/src/xenia/gpu/gpu.cc). +See the top of [src/xenia/gpu/gpu.cc](../src/xenia/gpu/gpu.cc). `--vsync=false` will attempt to render the game as fast as possible instead of waiting for a fixed 60hz timer. ### OpenGL -See the top of [src/xenia/gpu/gl4/gl4_gpu.cc](https://github.com/benvanik/xenia/blob/master/src/xenia/gpu/gl4/gl4_gpu.cc). +See the top of [src/xenia/gpu/gl4/gl4_gpu.cc](../src/xenia/gpu/gl4/gl4_gpu.cc). Buggy GL implementations can benefit from `--thread_safe_gl`. @@ -42,7 +62,7 @@ Playground tool. #### Shader Playground -Built separately (for now) under [tools/shader-playground/](https://github.com/benvanik/xenia/blob/master/tools/shader-playground/) +Built separately (for now) under [tools/shader-playground/](../tools/shader-playground/) is a GUI for interactive shader assembly, disassembly, validation, and translation. @@ -59,7 +79,7 @@ disassembly is broken. Finally, the right most box will show the translated shader in the desired format. For more information and setup instructions see -[tools/shader-playground/README.md](https://github.com/benvanik/xenia/blob/master/tools/shader-playground/README.md). +[tools/shader-playground/README.md](../tools/shader-playground/README.md). ### xe-gpu-trace-viewer @@ -95,6 +115,10 @@ you to seek through them in the trace viewer. These files will get large. ### Command Buffer/Registers +Registers documented at [src/xenia/gpu/register_table.inc](../src/xenia/gpu/register_table.inc). + +PM4 commands documented at [src/xenia/gpu/xenos.h](../src/xenia/gpu/xenos.h#L521). + ### Shaders * [LLVM R600 Tables](https://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/R600Instructions.td) diff --git a/docs/kernel.md b/docs/kernel.md new file mode 100644 index 000000000..82e2ed755 --- /dev/null +++ b/docs/kernel.md @@ -0,0 +1,42 @@ +# Kernel Documentation + +## Kernel shims +Xenia implements all kernel APIs as native functions under the host. + +When a module is loaded, the loader will find all kernel imports, put a syscall in +their place, then lookup a kernel export and link it to each import. The JIT will +generate a sequence of instructions to call into Xenia's export if it encounters a syscall. + +Currently, there are two ways an export can be defined - +[for example](../src/xenia/kernel/xboxkrnl/xboxkrnl_audio.cc): +* `SHIM_CALL XAudioGetSpeakerConfig_shim(PPCContext* ppc_context, KernelState* kernel_state)` +* `dword_result_t XAudioGetSpeakerConfig(lpdword_t config_ptr)` + +The `SHIM_CALL` convention is deprecated, but allows a closer look at the internals of how +calls are done. `ppc_context` is the guest PowerPC context, which holds all guest +registers. Function parameters are fetched from r3...r10 (`SHIM_GET_ARG_32`), and +additional parameters are loaded from the stack. The return value (if there is one) +is stored in r3 (`SHIM_SET_RETURN_32`). + +Details on how calls transition from guest -> host can be found in the [cpu documentation](cpu.md). + +The newer convention does the same, but uses templates to automate the process +of loading arguments and setting a return value. + +## Kernel Modules +Xenia has an implementation of two xbox kernel modules, xboxkrnl.exe and xam.xex + +### xboxkrnl.exe - Xbox kernel + +Defined under src/xenia/kernel/xboxkrnl. + +This is a slightly modified version of the NT kernel. Most of the APIs +are equivalent to ones you'd find on MSDN or other online sources. + +Source files are organized into groups of APIs. + +### xam.xex - Xbox Auxiliary Methods + +Defined under src/xenia/kernel/xam. + +This module implements functionality specific to the Xbox. \ No newline at end of file