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mckero
fdcbe80056
Second finding from the audit. TIM2 was covered by the catch-all stub, which returns
the last value written, so
uint32_t millis(void) { return LL_TIM_GetCounter(TIM2); }
returned 0 forever. All 17 call sites that measure elapsed milliseconds could never
see time pass -- a silent wrong answer rather than a hang, which is harder to notice
and was not noticed.
The counter is derived on read from QEMU_CLOCK_VIRTUAL rather than stored, with
CR1.CEN starting and freezing it and a CNT write rebasing it. Guest time here is not
proportional to wall time anyway, and code measuring elapsed milliseconds wants
something advancing at roughly the rate a human sees; this is explicitly not for
anything needing cycle accuracy.
Measured: 24358 ms, then 29527 ms five seconds later -- 5169 ms elapsed, so the rate
is right rather than merely non-zero. The test checks the rate for that reason: a
counter ticking at the wrong speed would satisfy "non-zero" and "increasing" and still
break every timeout.
AGENTS.md now carries the audit itself: a table of what the firmware actually drives
against what is modelled versus stubbed, and the point that answering reads is not the
same as being reproduced. The honest summary is that the digital side the firmware
depends on is reproduced, and the analogue side is not and cannot be.
Full run: 15 passed, 0 failed.