AnachronautandClaude Opus 5
b3726c950a
An arrow key has never reached this machine. Voyager threw it away for want of anywhere to put it, and a terminal sent ESC [ A, which arrived in the middle of whatever was being read and made it unrecognisable - typing Up at the CosmOS prompt put three bytes in the command line and got "I do not know". So the console names them: one byte each, 0x80 upward, above ASCII so nothing written before them can collide. Up, Down, Left, Right, Home, End and forward Delete, with room above for the paging and function keys. The console normalises, which is what it already does. Behind a window it turns the key somebody pressed into a byte; on a terminal it turns the sequence into the same byte. That is the act it has always performed on Return and Backspace, one layer further along, and it is why a program need not know which of the two it is talking to. What a key MEANS is not the console's business - that belongs to whoever is reading, the same way what is on a disk belongs to the system and what a drive is belongs to the machine. Translated only when standard input really is a terminal. Nothing else sends these sequences, a pipe holds exactly the bytes somebody put in it, and it keeps the Escape-or-Up timing problem out of every test here: a test writes the key values themselves. Line mode drops them, in both front ends, because line mode delivers characters and a line somebody else has finished editing cannot be moved about in. Press.sbx says what it was handed, in hexadecimal and by name, and reads a line before it reads keys so both halves of that rule are checked. Two recordings, one fed as standard input and one as a keyboard, agreeing byte for byte; each break fails exactly one of them. Three checks in terminal.sh type real escape sequences at a pseudo-terminal, which is the only place they are ever read as sequences: that they arrive as keys, that Escape alone is still Escape, and that a character typed straight after an escape is held rather than swallowed. Five recordings re-blessed for Press.sbx appearing on the shared disk, and the whole of that diff is the file's own line and the counts above it. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
179 lines
3.2 KiB
NASM
179 lines
3.2 KiB
NASM
; What the console just handed over, in hexadecimal and by name.
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;
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; The keys that are not characters - the arrows, Home, End and forward Delete - arrive as
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; the console's own values above ASCII rather than as the escape sequences a terminal sends
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; or as nothing at all, which is what a window used to make of them. This is what shows
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; that, and it shows both halves of the rule in one run:
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;
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; A LINE FIRST, read the way everything reads one. Line mode delivers characters, so the
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; keys are dropped before they reach the buffer and what comes back is what a person could
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; have typed. Pressing Up while something else is collecting a line does nothing, which is
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; an improvement on putting an escape and a bracket in the middle of it.
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;
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; THEN THE KEYS, in key mode, where a program has asked for every keystroke as it happens
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; and these are keystrokes like any other.
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;
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; Written by Anachronaut
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#Include services.asm
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#Program
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#Base 0x4000
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start:
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SETD.0 LineText
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CALL printString
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CALL newLine
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SETD.0 Buffer
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INIB 0d63
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CALL readLine
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SETD.0 Buffer
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CALL showBytes
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SETD.0 KeyText
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CALL printString
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CALL newLine
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INIA 0x01
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OUTA 0x02 ; Key mode. Nothing echoes, so everything below says what it saw.
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keyLoop:
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INA 0x00
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INIB 0xFF
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XOR
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BRQ keyDone ; Nothing more is coming.
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INIB 0x71 ; q, which is how this is stopped.
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XOR
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BRQ keyDone
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CALL showKey
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BRI keyLoop
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keyDone:
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RSTA
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OUTA 0x02 ; Line mode, the way it was found.
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SETD.0 DoneText
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CALL printString
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CALL newLine
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RSTA
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SWI osExit
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; DP0 names a string of bytes ending in a zero. Prints each as two hexadecimal digits, so
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; that what is in the buffer can be read rather than guessed at.
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showBytes:
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LDA.0
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BRA showBytesDone
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CALL printByteHex
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INIA 0x20
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OUTA 0x00
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INCD.0
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BRI showBytes
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showBytesDone:
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CALL newLine
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RET
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; A holds a key. Prints its value and then what it is.
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;
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; A survives a CALL, so the byte is still here after printing it - but only until something
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; else is put in A, which the space below does. So it is kept where the naming can find it.
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showKey:
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SETD.1 KeyByte
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STA.1
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CALL printByteHex
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INIA 0x20
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OUTA 0x00
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SETD.1 KeyByte
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LDA.1
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; XOR leaves the answer in Q and A alone, so one load stands for the whole ladder.
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INIB 0x80
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XOR
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BRQ keyUp
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INIB 0x81
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XOR
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BRQ keyDown
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INIB 0x82
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XOR
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BRQ keyLeft
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INIB 0x83
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XOR
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BRQ keyRight
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INIB 0x84
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XOR
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BRQ keyHome
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INIB 0x85
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XOR
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BRQ keyEnd
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INIB 0x86
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XOR
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BRQ keyDelete
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; An ordinary character, which is its own best name.
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OUTA 0x00
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CALL newLine
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RET
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keyUp:
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SETD.0 UpText
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BRI keySay
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keyDown:
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SETD.0 DownText
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BRI keySay
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keyLeft:
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SETD.0 LeftText
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BRI keySay
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keyRight:
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SETD.0 RightText
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BRI keySay
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keyHome:
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SETD.0 HomeText
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BRI keySay
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keyEnd:
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SETD.0 EndText
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BRI keySay
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keyDelete:
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SETD.0 DeleteText
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keySay:
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CALL printString
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CALL newLine
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RET
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#Data
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#Base 0x2000
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LineText:
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"a line, then keys. q stops."
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KeyText:
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"keys:"
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DoneText:
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"done"
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UpText:
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"up"
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DownText:
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"down"
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LeftText:
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"left"
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RightText:
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"right"
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HomeText:
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"home"
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EndText:
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"end"
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DeleteText:
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"delete"
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KeyByte:
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0x00
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Buffer:
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#Reserve 0d64
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#Vectors
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Boot start
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#Include console.asm
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