AnachronautandClaude Opus 5
3449405b18
CosmOS had 1,161 bytes of Program Memory left before the address applications load at, and Tab completion is not going to fit in that with anything to spare. So the wall moves up one page: the system keeps below 0x4FFF and 0x2FFF, and an application is based at 0x5000 and 0x3000. A PAGE IS A CHEAP THING TO GIVE IT AND AN EXPENSIVE THING TO RUN OUT OF. An application still has 44K of Program Memory before the vector table and the largest one here uses 7.5K, so what was taken from applications is space nothing has ever asked for - while what the system gained is the difference between building the next thing and counting bytes while building it. Not doubling, which was the version that would have cost application space worth minding. One page, and the same again when it is needed. Nothing in the machine knows where the wall is, so this is 34 #Base lines, one threshold in the fault handler, and the table in the CosmOS README that Tests/docs.sh reads its limits out of. The native assembler's scratch map had to move with it, and docs.sh said so before anything ran: its data reached 0x40D6 and its buffers began at 0x4000, so they were sitting on its variables. That file already carries a paragraph about the floor coming up and the map staying where it was. It has happened twice now, and been caught by a check the first time wrote. Twenty three recordings are the same runs a page higher. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
166 lines
3.1 KiB
NASM
166 lines
3.1 KiB
NASM
; Read a text file one screen at a time.
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;
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; Twenty two lines are shown before a prompt. Space advances another screen, Return one
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; line, and q gives the machine back to CosmOS. This is forward-only on purpose: the file
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; stream holds one block and never asks the whole document to fit in memory.
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;
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; Written by ChatGPT for Anachronaut's SplitBit
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#Include services.asm
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#Program
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#Base 0x5000
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start:
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SETD.0 Name
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INIB 0d63
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SWI osArgument
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SETD.0 Name
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LDA.0
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BRA noName
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CALL fileStreamOpen
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BNQ openFailed
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CALL fullPage
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nextBlock:
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CALL fileStreamNext
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BNQ readFailed
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PSHD.3
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POPB
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POPA
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SETD.2 Remaining
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STA.2
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INCD.2
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STB.2
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OR
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BRQ finished
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SETD.1 FileStreamBlock
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SETD.2 Remaining
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printLoop:
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LDA.1
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OUTA 0x00
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INIB 0x0A
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XOR
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BNQ bytePrinted
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SETD.3 LinesLeft
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LDA.3
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DECA
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STA.3
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BNA bytePrinted
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CALL pause
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BNQ finished
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bytePrinted:
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INCD.1
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CALL fileStreamTakeRemaining
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BRQ nextBlock
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BRI printLoop
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; Ask for one key without asking for Return. The console is put back immediately,
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; including on q and end of redirected input.
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pause:
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SETD.0 MorePrompt
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SWI osPrintString
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INIA 0x01
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OUTA 0x02
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INA 0x00
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PSHA ; Keep the key while A is used to restore line mode.
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RSTA
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OUTA 0x02
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POPA
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SETD.0 ClearPrompt
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SWI osPrintString
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INIB 0x71 ; q
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XOR
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BRQ pauseQuit
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INIB 0xFF ; end of redirected input
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XOR
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BRQ pauseQuit
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INIB 0x0A ; Return: one more line.
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XOR
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BRQ oneLine
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INIB 0x20 ; Space: one more screen.
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XOR
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BNQ pause ; Ignore every other key.
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CALL fullPage
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RSTA
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RSTB
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OR
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RET
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oneLine:
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SETD.3 LinesLeft
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INIA 0x01
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STA.3
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RSTA
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RSTB
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OR
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RET
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pauseQuit:
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RSTA
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INIB 0x01
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OR
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RET
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fullPage:
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SETD.3 LinesLeft
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INIA 0d22
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STA.3
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RET
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noName:
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SETD.0 Usage
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SWI osPrintString
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INIA 0d2
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SWI osExit
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; ---- What went wrong, in words ----
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;
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; It used to print the number the filesystem answered with, as "error 2". THERE IS NO SUCH
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; VOCABULARY: the library documents its answer as zero or not zero and never as a code, so
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; the number named nothing and could not be looked up - it just looked like it could.
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;
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; A name that is not on the disk is the only way opening fails that a person can do anything
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; about, and it is nearly always a name typed slightly wrong. Saying so is more use than any
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; number would have been.
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openFailed:
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SETD.0 OpenError
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SWI osPrintString
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BRI failed
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readFailed:
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SETD.0 ReadError
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SWI osPrintString
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failed:
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; ITS OWN EXIT, and it did not have one. This fell through into finished and reported
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; that everything was fine, having just printed the reason it was not - which nobody
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; noticed while the only reader was a person, who could see both.
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INIA 0d1
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SWI osExit
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finished:
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RSTA
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SWI osExit
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#Data
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#Base 0x3000
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Usage:
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"more: give me a file name
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"
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OpenError:
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"more: there is no file by that name
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"
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ReadError:
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"more: the disk would not give me that file
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"
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NewLine:
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0x0A 0x00
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MorePrompt:
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"-- more --"
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ClearPrompt:
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0x0A 0x00
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Name:
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#Reserve 0d64
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Remaining:
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0x00 0x00
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LinesLeft:
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0x00
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#Include fileStream.asm
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