AnyPS5/docs/dev
Dean Galvin 097566d547 fix(relinker): lower VRSQRTPS and VRCPPS to correctly rounded results for --to-intel
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.
2026-10-04 14:40:16 +13:00
..
BUILD.md docs(usage): add relinker usage md doc 2026-10-02 21:50:35 +03:00
CONVENTIONS.md refactor(docs): separated user and dev in docs + compatibility file 2026-09-28 22:58:17 +03:00
TechnicalDebt.md fix(relinker): lower VRSQRTPS and VRCPPS to correctly rounded results for --to-intel 2026-10-04 14:40:16 +13:00