docs(tech-debt): record the FORCE_DEGAMMA measurement on RDNA2
Co-Authored-By: Claude <noreply@anthropic.com>
This commit is contained in:
parent
619ec7ad39
commit
ec2df2691a
|
|
@ -362,7 +362,7 @@ Throughout the project, every function at every stage either **does exactly what
|
|||
- [Vector buffer offsets that are not a multiple of 4](../../core/shader/recompiler/SpirvBackend/src/SpirvMemory/SpirvMemoryInstructions.cpp) (shader recompiler) - dword accesses count whole dwords from the V# base, where the hardware reads the exact bytes at base + offset.
|
||||
- [Min/max S# reduction](../../core/libs/prx/libSceAgcDriver/Graphics/src/GuestSamplerResource.cpp) (libSceAgcDriver) - `FILTER_MODE` 1 and 2 use Vulkan's min and max reduction (the same `SQ_IMG_FILTER_MODE` values RADV programs). Measured on RDNA2 (gfx1035), not on the console: only texels of non-zero weight are reduced, and the weight is taken after rounding to the 8-bit subtexel grid (a sample within 1/512 texel of a centre reduces that texel alone); a driver with other `subTexelPrecisionBits` reduces a different set there. Gathers ignore the mode.
|
||||
- [Min/max S#](../../core/libs/prx/libSceAgcDriver/Graphics/src/GuestSamplerResource.cpp) (libSceAgcDriver, shader recompiler) - throws with anisotropy, a linear mip filter, depth or color-texture compare, or bilinear filtering of an image the recompiler point-samples (sint, converted, depth-bits).
|
||||
- [FORCE_DEGAMMA](../../core/libs/prx/libSceAgcDriver/Graphics/src/Sampler.cpp) (libSceAgcDriver) - an S# that forces sRGB decoding adds nothing to an sRGB texture, as in shadPS4 (PS4); not measured on gfx10. Other textures throw.
|
||||
- [FORCE_DEGAMMA](../../core/libs/prx/libSceAgcDriver/Graphics/src/Sampler.cpp) (libSceAgcDriver) - an S# that forces sRGB decoding adds nothing to an sRGB texture, as in shadPS4 (PS4). Measured on RDNA2 (gfx1035), not on the console: `8`, `8_8` and `8_8_8_8` sRGB textures sample bit for bit the same with and without the bit (point and bilinear; BC formats not measured). Other textures throw; on the same hardware their UNORM `8`, `8_8` and `8_8_8_8` forms sample bit for bit as the sRGB format (decoded before filtering).
|
||||
- [Tessellation factor ring](../../core/libs/prx/libSceAgcDriver/State/src/Configuration.cpp) (libSceAgcDriver) - `sceAgcDriverSetTFRing` records the ring and `sceAgcDriverGetTFRing` reports it. Before a title sets one, it reports the console's default, 0xFF0000000 and 128 KiB, as measured in [PS5_Vulkan's hardware findings](https://github.com/mihawk-99/PS5_Vulkan/blob/fde9e3798c2ec1d8fccc90d5067cd6060490607f/docs/HARDWARE_FINDINGS.md). Nothing is written to the recorded ring: tessellated draws run as Vulkan tessellation stages, which keep their factors on the host, so a title that reads tessellation factors from the ring finds none. A null base or a zero size throws; [ps5-opengl's AGC runtime](https://github.com/blackbearreloaded/ps5-opengl/blob/67c873f985eaefe0a72f713529e5632eaa01139c/src/platform/ps5_agc_native_runtime.c) calls `sceAgcDriverSetTFRing(0, 0)` in its cleanup, and what that does on the console is unknown.
|
||||
- [Raw `buffer_load_dwordx2`](../../core/shader/recompiler/SpirvBackend/src/SpirvMemory/SpirvMemoryInstructions.cpp) is one 64-bit access on the hardware (with or without glc), so it never sees half of a `buffer_atomic_swap_x2`. Only a glc load that is 8-byte aligned and in bounds, in a program that has the 64-bit storage view (it uses 64-bit buffer atomics), is read with one 64-bit atomic load; every other dwordx2 load is two dword loads and can tear against a concurrent 64-bit write: loads without glc, and loads in a program without 64-bit buffer atomics while another shader writes the pair with `swap_x2`.
|
||||
- [DS src2 operations](../../core/shader/recompiler/Translation/src/MemoryInstructions/SharedMemoryInstructions.cpp) (`ds_*_src2_*`, GFX10.1 only) read `DS[B]`, with `B = A + 4 * sext(offset1[6:0]:offset0)`, and then update `DS[A]` with the matching 32-bit atomic, so the read of `B` is not atomic with the update of `A`. The form that takes the offset from the address (`offset1[7]` set), the 64-bit forms and GDS throw: whether the LDS address keeps `A[31:17]` in that form, and whether the 64-bit forms scale the offset by 4 or 8, is not documented. `ds_min_src2_f32`, `ds_max_src2_f32` and `ds_add_src2_f32` throw: on RDNA2 (gfx1035, the oracle's hardware, which has no src2 opcodes) `ds_min_f32`, `ds_max_f32` and `ds_add_f32` ignore `IEEE_MODE` but depend on whether f32 denormals are flushed (28, 28 and 12 of 196 special rows differ), and that is not modelled for LDS float atomics yet (#981).
|
||||
|
|
|
|||
Loading…
Reference in New Issue