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Let the reset button reach a machine that has stopped

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The gesture rebooted CosmOS and could not reboot picture.bin, which is the case it was added
for. picture.asm ends in HALT, and a halted machine runs no instructions - so nothing ever
reached the code that notices a reset, because a reset is noticed BETWEEN INSTRUCTIONS and
there are none. It only ever worked because CosmOS was still going.

Which is backwards: a machine that is not going anywhere is exactly the one worth restarting,
and it is the one that cannot hear a request by itself. The restart is lifted out of the run
loop into machineTakeReset, and the window asks every frame whether the machine is running or
not.

NAMED AS EMULATOR MAGIC, because it is. There is no reset line on this machine and no keyboard
controller to assert one; the window reaches in and sets the same flag the machine port sets.
When those are designed, a keyboard controller will have to see the gesture and pull reset
regardless of what the CPU is doing - which is the property that matters and the one a port
write can never have, since a port write needs a program willing and able to make it. The
shape of that is already visible here: asking every frame rather than leaving it to the
machine to notice is what a line does.

A restart now clears the cycle limit as well, since a machine stopped for reaching one is
another thing somebody would press the button over.

The three existing reset tests still pass, and they are the ones that matter: they exercise
the same restart through the machine port. What no test reaches is the gesture itself, which
exists only when there is a window.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
This commit is contained in:
Anachronaut
2026-08-29 14:48:31 -04:00
co-authored by Claude Opus 5
parent 8c6ed62044
commit adefce975b
4 changed files with 79 additions and 21 deletions
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@@ -62,7 +62,18 @@ imitate a login screen. On Windows an application cannot see it without a kernel
on Linux the desktop takes it. It is unavailable for the same reason it seemed right.
It does exactly what writing to the machine port does: the machine starts the way it started,
so the boot chain runs again and finds whatever the disk now says to run.
so the boot chain runs again and finds whatever the disk now says to run. **And it works on a
machine that has stopped** - one that halted, or faulted, or is a bare metal demo that ended.
That is the whole point of a button: a machine which is not going anywhere is exactly the one
worth restarting, and it is the one that cannot notice a request by itself, because a reset is
otherwise seen between instructions and a halted machine runs none.
This part is **emulator magic and known to be**. There is no reset line on this machine yet
and no keyboard controller to assert one; the window reaches in and sets the same flag the
machine port sets. When those are designed, a keyboard controller will have to see the gesture
and pull reset regardless of what the CPU is doing - which is the property that matters, and
the one a port write can never have, since a port write needs a program willing and able to
make it.
That is what makes a bare metal program escapable. `Once` puts one in front of the next start
and deletes the request before jumping, so a demo that has taken the whole machine is one