The f16 forms of v_fma_mix computed an f32 FMA and converted it to f16,
so a result that lands on an f16 tie after the f32 rounding was rounded
twice. RDNA2 rounds the exact product-sum once. They now use the exact
f64 path of v_interp_p2_f16 and flush f32 sources like v_fma_mix_f32.
They follow the f16 round and denormal fields on hardware, so another
f16 mode throws, as packed f16 does.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
VOP3 0x140 is v_mad_legacy_f32 on gfx10.1. Measured on gfx1010 (RX 5700
XT) in wave32 and wave64, IEEE 0 and 1 and f32 denormal modes 0 to 3, it
rounds the product before the add, flushes f32 denormal sources, product
and result in every mode, and gives a +0 product for a zero factor.
The translation multiplies, applies the zero rule and flushTinyProduct,
adds, and keeps the nanResultF32 wrapper. f32DenormalFlushFor returns 3
for the instruction before reading FLOAT_MODE. A sum of two zeros takes
its sign on the bits, as lavapipe returned -0 for +0 + -0. The execution
test pins the measured results and compares NaN bits exactly. RDNA2
(gfx1031), where the encoding is v_fma_legacy_f32 and fused, is noted in
TechnicalDebt.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The padded, exact-fit and invalid-conversion swprintf checks come from #1512.
Co-Authored-By: Noface07 <yuvrajsoni7@gmail.com>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ULF8vCbJFyzxVsW3SfiWC5
A CMASK that was neither all fast-cleared nor all expanded threw, so a
title that fast clears a target and then draws over part of it before the
eliminate could not run past it.
The CMASK is now decoded tile by tile: one nibble per 8x8 tile in
1024x512 metablocks of 4 KiB, addressed with the pipe-aligned
SW_64KB_Z_X CMASK equation for 16 pipes (addrlib
GFX10_CMASK_SW_PATTERN, Gfx10Lib::HwlComputeCmaskAddrFromCoord). Code 0
stores CB_COLOR_CLEAR_WORD into the tile's texels, 0xF keeps them; any
other code, a cleared tile of a DCC target and any other CMASK swizzle
mode throw. Edge tiles are included and the CMASK is then stored as
expanded.
For a resident target whose CMASK is host-imported the clear is a
compute pass recorded in stream order: it reads the nibbles from the
import, stores the clear into the cleared tiles through a UINT view of
the image and fills the CMASK expanded, so nothing waits for pending GPU
writes of the CMASK. Invalid codes it reads set a bit that the next
materialization throws on. Otherwise the CPU reads the CMASK and stores
the cleared tiles into guest memory, or fills the resident image when
every tile is cleared. A CMASK nothing has stored over since it was
expanded is skipped.
The decode requires CB_COLOR_ATTRIB3 FMASK_SW_MODE SW_64KB_Z_X with
CMASK_PIPE_ALIGNED, a 4 KiB aligned writable CMASK and texels of at most
64 bits, and CMASK_BASE_EXT is part of the draw key.
Tests: CMASK sizes and nibble addresses against addrlib; decode
rejections and draw key coverage; CPU eliminate of full, partial,
out-of-range-nibble and DCC decompress cases and invalid codes. The new
agc_driver_cmask_fast_clear GPU test draws over fast-cleared and partly
fast-cleared linear and SW_64KB_R_X targets, eliminates partial, edge
and checkerboard CMASKs through the compute pass and checks that an
invalid code it reads throws.
Measured on RDNA2 (gfx1036) with tools/hw-oracle in wave32 and wave64:
s_call_b64 writes PC + 4 to the link pair and branches to
PC + 4 + signext(SIMM16) * 4, and s_setpc_b64 of the link returns;
s_swappc_b64 with SDST 125 branches and leaves a marker pair untouched, so
its decode as s_setpc_b64 matches, and with an SGPR destination the link is
PC + 4.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012GLfKH7Sqe51wX254k1XsV
A 3D image access bound to a 2D T# matched no runtime image mode and
threw "image descriptor is incompatible with the static runtime image
interface" (Sonic Origins, #2023). CouchRiv measured RDNA2 (gfx1036)
with the hardware oracle: image_sample_lz with dim 3D ignores r and
reads the (u,v) texel, and image_load reads the (x,y) texel when z is
0 and returns zero otherwise. Add a 2D mode for 3D accesses whose only
uses are those two forms, and make the load return zero for z != 0.
Every other access keeps throwing.
Fixes#2023
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Without VK_KHR_fragment_shader_barycentric the recompiler dropped
v_interp_p1_f32 and made v_interp_p2_f32 read the attribute Vulkan
interpolated, but never wrote the I/J VGPRs: a pixel shader that read
them for anything else got 0, and v_interp_mov_f32 of P10/P20 (or P0 of
an interpolated input) needed PerVertexKHR and failed pipeline
validation.
The fallback translation now loads the I/J VGPRs and marks v_interp_p1
and v_interp_p2 with witnesses. After the front-end simplification
(SSA, folding, DCE, read-lane and masked-select elimination),
HostInterpolationChecker requires every p2 to read its J, and its p1's
I, from a barycentric of the parameter's kind, every p1 result to reach
only the matching p2 (through a write masked by the p2's EXEC, whose
inactive lanes keep the old register), no parameter read as raw
vertices and no slot shared by different interpolations. It then
lowers the witnesses to the host-interpolated attribute as before,
reruns DCE and masked-select elimination, and accepts the program only
when no barycentric read remains, so reusing the I/J VGPRs after
interpolating keeps host interpolation and the previous SPIR-V. Any other
program is translated with the barycentric path and marked as emulated:
its barycentrics become vec3 inputs (NoPerspective for the linear
weights) and its per-vertex parameters flat vec4[3] inputs, placed in
the free locations by LayoutBarycentricEmulation. The driver then
inserts a generated geometry stage between the vertex and fragment
shaders that copies the position and parameters, writes the one-hot
weights of each vertex and the three vertices' parameter values, so the
rasterizer interpolates the same weights the extension provides.
The stage needs geometryShader and a vertex shader before it;
tessellation, mesh and rect-list pipelines, other primitive types and
interfaces beyond 32 locations or the device's geometry limits throw.
CompiledShaderArtifact carries the emulation (shader disk cache format 21).
Hardware snaps window corners to 1/256 pixel before interpolating
(measured by yahya308 on an RTX 4070 Laptop and a Radeon 780M in #1547);
lavapipe snaps only for coverage (lp_rast.h FIXED_ORDER 8), so the test
accepts either reference per pixel at the original 1e-4 margin.
Sources:
- v_interp_p1_f32/v_interp_p2_f32/v_interp_mov_f32 semantics (P0,
P10, P20, I/J): AMD RDNA2 ISA, "Parameter Interpolation".
- BaryCoordKHR/BaryCoordNoPerspKHR weights and PerVertexKHR vertex order:
SPV_KHR_fragment_shader_barycentric, VK_KHR_fragment_shader_barycentric.
- Geometry shader triangle input order and provoking vertex: Vulkan
specification, "Primitive Topologies" and "Geometry Shading".
- Interpolation decorations decided by the fragment input: Vulkan
specification, "Interpolation Decorations".
- lavapipe interpolation: Mesa src/gallium/drivers/llvmpipe/lp_rast.h
(FIXED_ORDER 8), lp_setup_tri.c (subpixel_snap for coverage only),
lp_state_setup.c (init_args, plane setup from float positions).
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