0x64 counted only the RECORDED pads. So a controller plugged into Voyager
reported its buttons perfectly, and every game asking whether there was a
controller was told no - which is exactly what Lunar Porter asked, once,
at startup, before falling back to the console for the rest of the run.
The cause is worth naming: a front end calls padSet every frame for every
pad, so "held nothing" is the commonest thing it says and cannot also mean
"there is no pad here". Connected is said separately now. Pad nought is
always there behind a window, because the keyboard is behind it - which is
the useful answer rather than the literal one.
And Pad.asm, which is what should have existed before any of that guessing
began. It prints a line whenever a pad changes, and tells apart the three
states that look identical from inside a game that will not respond: one
nobody noticed, one mapped to nothing, and a mapping that is wrong.
WHY A PROGRAM AND NOT A PRINT IN THE FRONT END: because the question is
what the MACHINE can see. A front end reporting what it thinks it is
sending answers a different question, and the gap between those two is the
whole of this bug.
It also found that osPrintNumber takes A as the HIGH half - the same way
round as the shift register and every other pair here, and not what a byte
in A wants. Every value came out 256 times too big.
Gravity is one frame in ten rather than six. The ratio between thrust and
gravity is the feel; how often the tick comes round is how fast that feel
arrives, and one in six was still touchy. Same lander, more time to think.
And the verdict waits for a key. It printed and left immediately, taking
the screen with it - so the one thing worth seeing, the lander sitting on
the ground it had just reached, was gone before it could be looked at.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
The console says WHICH KEY WENT DOWN, which is the right shape for typing
and the wrong one for playing. A game wants to know what is being held,
this frame, possibly several things at once, and a stream of presses
cannot say that: a key that is down and staying down sends nothing at all.
Lunar Porter's thrust is a burn per press for exactly that reason.
So a pad is its own device on ports 0x60 to 0x6F, reporting a LEVEL. One
read gives every button at once, holding is the natural thing to express,
two directions together cost nothing, and reading does not consume it - a
game may ask twice in a frame and be told the same thing both times.
Four of them, because a party is four. They cost a port each and nothing
at all when unused. The directions are the low nibble so "which way" is an
AND with 0x0F; the buttons are the high nibble for the same reason. 0x64
says which are really there, so a game can ask for a controller rather
than sitting silent while somebody presses things at it. They never
interrupt: a game polls once a frame because that is when it draws.
KEY-UP ON THE CONSOLE WAS THE OTHER WAY TO DO THIS AND WAS REJECTED. A
terminal hands over characters and can never report a key coming up
however it is asked, so it would have been a thing that worked behind a
window and silently did not down a wire. A separate device can honestly
say it is not there.
Voyager drives pad nought from the keyboard as well as from any real
controller, OR-ed rather than chosen between, so a game written for a pad
is playable on a machine with none and unplugging one mid-game does not
leave somebody holding nothing.
And a recorded path, which is what makes any of it testable: --pad names a
file of one byte a frame, and the manifest has an eighth column for it.
A BYTE A FRAME AND NOT A BYTE A READ - a level asked twice in one frame
has to answer the same both times, and a file that advanced per read would
depend on how the program happened to be written. Voyager's own tests run
headless with nobody holding anything, so without this the device would be
exercised only by somebody playing: the state the console's line editing
was in when it broke twice in two days.
0x50 is the timer, not free. The block this went in was chosen after
looking rather than before.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
AnachronautandClaude Opus 5