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#96: TRACE THE CLOCK ORIGIN -- the pod ran at 28 fps (byte-proven); myomer heat re-bracketed to 14 Hz effective

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epilectrik: "the issue seems to be related to a tick rate that advances the
heat accumulation... i need to trace out what the clock origin was."  Traced.

THE CLOCK ORIGIN [T1]: the DOS binary keeps its engine frame rate in the
global DAT_0052140c, set once at startup:
    0x401ace:  mov [0x52140c], 0x41E00000   = 28.0f     (nominal)
    0x401ada:  mov [0x52140c], 0x4191A6E0   = 18.2065f  (BIOS-tick fallback)
The DOS main pushes it straight into the ApplicationManager ctor (0x401189:
push [0x52140c]), and ~90 sites across the image fmul/fdiv by it -- it is THE
per-frame<->per-second conversion scalar of the whole 1995 engine.  The engine
executes every interesting master every frame and every executable subsystem
every entity tick (UPDATE.cpp / ENTITY.cpp, T0 -- no throttle at any layer),
so subsystem Performance cadence == this rate: the pod's myomer tick was
NOMINALLY 28 Hz.  My previous 30 Hz reference (the i860 BOARD frame) was
wrong by 7%, not the 2x the veterans hear.

THE RESIDUAL IS EFFECTIVE RATE, NOT NOMINAL: Oracle, on the halved build,
still asks "If you could please halve the myomer heat rate again.  We will
bracket to something reasonable."  A 486 host missing beats halves the real
Performance cadence without changing any constant -- and the 18.2 fallback
existing at all says slow paths were expected.  Statics cannot settle the
in-pod effective rate, so his bracket is the right instrument:

    effective default = 28 [T1 nominal] x 0.5 [T3 testimony calib] = 14 Hz
    BT_MYO_HZ=<hz> still overrides absolutely for bracketing
    the resolved rate now logs under BT_MYO_LOG, tier tags inline

Measured (Owens, seek 4, flat out): peak T 1007 -> ~640, degradation never
reached -- the halving Oracle requested, delivered as one auditable knob
instead of a silent constant edit.

KB: decomp-reference.md gains the DAT_0052140c section (~90 consumer sites --
whenever the decomp shows an unexplained mul/div by _DAT_0052140c it is
per-second<->per-frame at 28); btl4main.cpp's "30 = pod authentic" pacer note
corrected (30 kept deliberately for display smoothness, the divergence now
documented).  Candidate follow-up recorded: the frame-rate-dependent particle
trail density (rendering.md) should normalize against the same 28, which may
bear on Ronin's smoke-density report (#114).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
Joe DiPrima
2026-08-02 09:39:00 -05:00
co-authored by Claude Opus 5
parent c791fae0f8
commit c28555bdc9
3 changed files with 58 additions and 14 deletions
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game/btl4main.cpp
+8 -3
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@@ -1512,9 +1512,14 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
// (end_of_frame = now + 1/frameRate) degenerated and the game ran at a
// timer-quantized ~15 FPS (66-70ms frames measured) on ANY hardware.
// Default 60; env TARGETFPS still overrides (clamped to sanity).
int target_fps = 30; // the pod's authentic rate; frame work (~20-40ms in
// this build) misses 60Hz beats -> jitter, but holds
// 30 rock-steady. TARGETFPS env still overrides.
int target_fps = 30; // NOTE: the pod's byte-proven NOMINAL rate is 28
// (DAT_0052140c = 28.0f @0x401ace; 18.2065 BIOS
// fallback @0x401ada -- decomp-reference.md). We
// keep 30 for display smoothness; anything that
// must match the pod's per-tick math normalizes
// itself (e.g. the myomer kinetic term). Frame
// work (~20-40ms) misses 60Hz beats -> jitter,
// holds 30 steady. TARGETFPS env overrides.
{
const char *tf = getenv("TARGETFPS");
if (tf != 0)