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pureboot: the activation countdown in the narrowest type that holds it

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The fixed-baud window counted down a uint32 where almost every window fits
24 bits; the countdown now takes avr::uint24_t when the poll budget allows
(the autobaud budget's own choice), uint32 past 16.7M polls — four bytes
off every fixed-baud image on every chip, the full suites green on the
changed window. The README size table is refreshed — its autobaud column
had also gone stale by the no-assembly pass's measurement-loop win, which
nothing gated: sizes.py check-readme now runs as the gate's final stage,
where every tree is freshly built and the table can actually be held.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
BlackMark
2026-07-28 14:47:29 +02:00
parent 321ff8a4ee
commit c535c4756c
4 changed files with 29 additions and 18 deletions
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7
pureboot/pureboot.cpp
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@@ -351,9 +351,14 @@ consteval std::uint32_t window_polls()
return timeout_seconds * static_cast<std::uint32_t>(dev::clock.hz / link::poll_cycles);
}
// The countdown in the narrowest type that holds it: a fourth byte would
// cost a wider decrement chain at every poll for range most windows never
// use (the autobaud budget makes the same choice).
using window_t = std::conditional_t<window_polls() <= 0xffffff, avr::uint24_t, std::uint32_t>;
bool pending_before_deadline()
{
std::uint32_t polls = window_polls();
window_t polls = window_polls();
do {
if (link::pending())
return true;