RSQRTPS and RCPPS are approximations whose low bits differ between Intel
and AMD. Intel returns 0x3F7FF000 for 1/sqrt(1.0), and two Newton-Raphson
steps on it settle on 0.99999994 instead of 1.0. PPSA21564 renormalises
its spring quaternions that way: an identity quaternion keeps w at
0.99999994 with a zero axis, its axis-angle conversion then normalises the
zero axis into NaNs, and the NaN bone poses reach keyframed physics bodies.
A NaN body later moves to an invalid broadphase cell and the game crashes
a few seconds into its hub level.
--to-intel now replaces the VEX.128 register forms with an out-of-line stub
that computes 1/sqrt(x) with SQRTPS and DIVPS (1/x with DIVPS), keeping
the upper half of the destination cleared and the scratch register intact.
A site with no room for the jump, including one followed by a branch
target or a RIP-relative instruction, keeps the native instruction and is
reported as kept instead of failing the relink.
agc_driver_vopc_compare failed on every Linux runner with an
AVX512-FP16 Xeon (Sapphire, Emerald and Granite Rapids) and passed on
AMD EPYC and Ice Lake runners. Ubuntu 24.04's lavapipe compiles with
LLVM 20.1.2, which on these CPUs merges a masked fcmp ult/uge on half
vectors with the same compare of swapped operands, so v_cmp_nle_f16,
v_cmp_nlt_f16 and v_cmpx_nle_f16 return the result of their mirror.
The recompiler's SPIR-V is the same on every device and correct.
GALLIUM_OVERRIDE_CPU_CAPS=avx keeps LLVM off AVX-512, so every runner
compiles the tests the same way.
GCC gives C code built with -fexceptions, and cleanup-only functions
after link-time optimization, the C personality __gcc_personality_v0.
The unwinder accepted only its own C++ personality, so an exception
thrown through such a frame was never caught.
libc now provides the C personality, which never catches and installs
the frame's cleanup landing pad in the cleanup phase, and the unwinder
calls it for those frames.
PPSA21564's galaxy map renders a 1920x1080 surface as a color target whose
CB names DCC keys at one address and then writes it from a compute shader
whose T# names keys at another. Both key ranges read uncompressed every
frame, but the storage cache remade the surface's image whenever a
descriptor named metadata other than the image's, so the image was
flushed, destroyed, created and uploaded twice a frame (1231 constructions
in a 56 s scene), with the views and draw recipes built on it thrown away
each time.
A descriptor naming other keys now keeps the image when the move is
unobservable: the image's own keys and the named keys both read
uncompressed, and its content was neither uploaded nor filled under a
clear code. That is exactly the content an image made under the named
keys would hold once this one's pending results were stored. Any other
case (a fast clear of either key range, a register clear, an image
holding a clear) still remakes the image as before, so clears of the new
keys reach it and pending results are stored first.
Every proof that stands in for a lookup checks the same rule: the sampled
view hit, the fast revalidation of views and storage elements (storage
elements now record their descriptor's keys), the own-object refresh, and
the draw recipe's resident targets. Named-key scans keep per-image proofs,
so a repeated check costs no scan while the key bytes are unstamped.
agc_dcc_key_sharing drives KeysServeSurface, the rule ServesKeysAt uses,
through a model of the storage cache.
Driver::Submit checks the title's submission packet, which the title
passes on its own thread stack. Host thread stacks are neither registry
mappings nor write-watched, so no page-state cache covers them and on
Linux every check scans /proc/self/maps line by line: about 1.5 ms per
submission on the render thread of PPSA21564 (66% of that thread's
samples in perf at the title).
A range between the calling thread's current frame and its stack's top
holds the frames of every caller, so it is mapped readable and writable
for as long as the call lasts; verify() now accepts it without a query.
A thread on another stack (a fiber's, a signal stack) has its frame
outside the thread's bounds and still gets the page query, as does any
range that runs past the stack's top or starts below the frame.
GetCurrentThreadStackLimits needs _WIN32_WINNT 0x0602 on MinGW, as
libkernel already sets; GuestMemory.cpp is compiled by several targets,
so the definition is a property of the source file.
A CB metadata pass (and a resident target's register-clear check) read the
DCC keys with CurrentDccKeys, which waited for the GPU whenever recorded
work wrote the key range. In the intro video of PPSA21564 about 800 passes
per 10 s waited about 1.8 ms each, and every one of those waits was behind
a key store whose result the driver already knew: its own uncompressed key
store, or a title fill of uniform keys recorded on the GPU.
Pending-write notes now carry a serial in recording order, and the key
memo remembers the note of the store it describes. When the newest
pending note over the keys is that store's own note, nothing recorded
after it writes the keys, so they read as the store's keys without a
wait. Any later writer, a range the store does not cover, or a unit
shadow over the keys waits as before.
Dean