CosmOS pre-alpha and launchable application versions of old programs.
This commit is contained in:
Anachronaut
@@ -0,0 +1,388 @@
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; console.asm
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; Talking to the console.
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;
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; This is the modern replacement for print.asm, which was written for a machine with one
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; Data Pointer and no vector table. The old one is left where it is, because the programs
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; that include it still work and are meant to keep working.
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;
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; Two things are different here, and both are deliberate.
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;
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; There is no branch at the top. print.asm begins with BRI start, so that a program
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; including it arrives at its own entry point instead of falling into the library. That
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; was the only way to do it before the Boot vector existed. A program including this file
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; says where it begins in its own Vector Segment:
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;
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; #Vectors
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; Boot start
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;
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; And every routine here names the Data Pointer it works through rather than assuming the
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; only one. A pointer handed in is DP0. Nothing here disturbs what the caller left in
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; DP3, which is the one a return survives in.
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;
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; What a routine gives back is in Q, because Q and DP3 are the only things a RET does not
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; put back the way it found them.
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;
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; Written by Anachronaut
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#Program
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; ---- Characters and strings ----
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; A line feed.
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newLine:
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INIA 0x0A
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OUTA 0x00
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RET
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; DP0 names a string ending in a zero byte. Prints it.
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printString:
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LDA.0
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BRA printStringDone
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OUTA 0x00
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INCD.0
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BRI printString
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printStringDone:
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RET
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; A holds how many spaces to print. None is a fair answer, and prints nothing.
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printSpaces:
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BRA printSpacesDone
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INIB 0x20
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printSpacesLoop:
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OUTB 0x00
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DECA
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BNA printSpacesLoop
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printSpacesDone:
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RET
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; ---- Hexadecimal ----
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; A holds a byte. Prints it as two hexadecimal digits, high one first.
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;
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; A and B are a circular shift register sixteen bits long, so rotating right four times
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; with B empty walks the high nybble down into place and parks the low one in B. The call
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; between the two halves puts A and B back as they were, which is what lets the second
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; rotation find the low nybble still waiting.
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printByteHex:
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RSTB
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SHR SHR SHR SHR
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CALL printHexDigit
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RSTA
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SHL SHL SHL SHL
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CALL printHexDigit
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RET
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; DP0 names two bytes, most significant first, the way every number on a SplitBit disk is
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; stored. Prints them as four hexadecimal digits.
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printWordHex:
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LDA.0
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CALL printByteHex
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INCD.0
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LDA.0
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CALL printByteHex
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RET
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; A holds a nybble. Prints the one character that stands for it.
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printHexDigit:
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INIB 0d10
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CCF
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SUB
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BRC printDecimalDigit ; Under ten, so it is a plain digit.
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INIB 0x37 ; 'A' is ten, so this is the offset that gets there.
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CCF
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ADD
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OUTQ 0x00
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RET
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; A holds a digit from zero to nine. Prints it.
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printDecimalDigit:
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INIB 0x30
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CCF
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ADD
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OUTQ 0x00
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RET
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; ---- Decimal ----
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; A holds a byte. Prints it in decimal, without leading zeroes.
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printByteDecimal:
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SETD.0 ConsoleValue
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STA.0
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SETD.1 ConsoleLeading
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RSTA
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STA.1 ; Nothing has been printed yet.
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INIA 0d100
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CALL printBytePlace
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INIA 0d10
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CALL printBytePlace
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; Whatever is left is the ones, and it prints whether or not it is a zero, because a
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; number has to show at least one digit.
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SETD.0 ConsoleValue
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LDA.0
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CALL printDecimalDigit
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RET
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; A holds a power of ten. Counts how many times it comes out of ConsoleValue, prints that
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; as a digit, and leaves the remainder behind. A leading zero prints nothing.
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printBytePlace:
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SETD.2 ConsoleBytePower
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STA.2
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SETD.0 ConsoleValue
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SETD.1 ConsoleCount
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RSTA
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STA.1
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printBytePlaceLoop:
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LDA.0
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LDB.2
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CCF
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SUB
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BRC printBytePlaceDone ; It went below zero, so it does not come out again.
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STQ.0
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LDA.1
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INCA
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STA.1
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BRI printBytePlaceLoop
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printBytePlaceDone:
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LDA.1
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BNA printBytePlaceShow
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; The digit is a zero, which only prints if something has been printed before it.
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SETD.2 ConsoleLeading
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LDA.2
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BRA printBytePlaceQuiet
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RSTA
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printBytePlaceShow:
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CALL printDecimalDigit
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SETD.2 ConsoleLeading
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INIA 0x01
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STA.2
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printBytePlaceQuiet:
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RET
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; DP0 names a two byte number, most significant byte first. Prints it in decimal, without
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; leading zeroes. Sixty five thousand five hundred and thirty five is the largest thing it
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; can be handed, which is the whole of an address, so nothing overflows this.
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printWordDecimal:
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SETD.1 ConsoleWord
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CALL consoleCopyWord
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SETD.1 ConsoleLeading
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RSTA
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STA.1
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SETD.0 ConsoleTenThousand
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CALL printWordPlace
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SETD.0 ConsoleThousand
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CALL printWordPlace
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SETD.0 ConsoleHundred
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CALL printWordPlace
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SETD.0 ConsoleTen
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CALL printWordPlace
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; What is left is under ten, so it is in the low byte and it is the last digit.
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SETD.0 ConsoleWord
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INCD.0
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LDA.0
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CALL printDecimalDigit
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RET
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; DP0 names a power of ten, two bytes of it. The same counting as printBytePlace, done
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; sixteen bits wide.
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printWordPlace:
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SETD.1 ConsolePower
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CALL consoleCopyWord
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SETD.1 ConsoleCount
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RSTA
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STA.1
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printWordPlaceLoop:
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CALL consoleTakePower
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BNQ printWordPlaceDone
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SETD.1 ConsoleCount
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LDA.1
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INCA
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STA.1
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BRI printWordPlaceLoop
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printWordPlaceDone:
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SETD.1 ConsoleCount
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LDA.1
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BNA printWordPlaceShow
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SETD.1 ConsoleLeading
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LDA.1
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BRA printWordPlaceQuiet
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RSTA
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printWordPlaceShow:
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CALL printDecimalDigit
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SETD.1 ConsoleLeading
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INIA 0x01
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STA.1
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printWordPlaceQuiet:
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RET
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; Takes ConsolePower out of ConsoleWord, if it comes out at all. Q is zero if it did, and
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; then ConsoleWord is the smaller for it. If it did not, ConsoleWord is left alone.
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;
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; The subtraction is done into a spare word rather than in place, because whether it fits
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; is not known until the high half is done, and by then an in place low half would already
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; have been spent.
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;
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; The low half clears the Carry Flag first and the high half does not: the borrow the low
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; half leaves behind is exactly what the high half has to subtract as well. Nothing
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; between them disturbs it, since only the arithmetic instructions and CCF touch it.
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consoleTakePower:
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SETD.0 ConsoleWord
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INCD.0
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SETD.1 ConsolePower
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INCD.1
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LDA.0
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LDB.1
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CCF
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SUB
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SETD.2 ConsoleSpare
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INCD.2
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STQ.2
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SETD.0 ConsoleWord
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SETD.1 ConsolePower
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LDA.0
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LDB.1
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SUB
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BRC consoleTakeNothing
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SETD.2 ConsoleSpare
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STQ.2
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SETD.0 ConsoleSpare
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SETD.1 ConsoleWord
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CALL consoleCopyWord
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RSTA
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RSTB
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CCF
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ADD ; Q is zero: it came out.
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RET
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consoleTakeNothing:
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RSTA
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INIB 0x01
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CCF
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ADD ; Q is one: it did not.
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RET
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; Two bytes from DP0 to DP1, most significant first.
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consoleCopyWord:
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LDA.0
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STA.1
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INCD.0
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INCD.1
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LDA.0
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STA.1
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RET
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; ---- Reading ----
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; DP0 names a buffer and B says how many characters it holds, not counting the zero byte
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; that ends it. Reads a line from the console into it. Q is how long the line turned out
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; to be.
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;
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; A line longer than the buffer is cut short, and the rest of it is read and thrown away
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; rather than left to turn up as the next line.
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;
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; ConsoleEndOfInput is set if the console ran out instead of ending a line. That is a
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; different thing from an empty line, and a program that reads until there is no more has
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; to be able to tell them apart.
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readLine:
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SETD.1 ConsoleRoom
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STB.1
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SETD.1 ConsoleLength
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RSTA
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STA.1
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SETD.1 ConsoleEndOfInput
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STA.1
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readLineNext:
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INA 0x00
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INIB 0x0A
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CCF
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SUB
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BRQ readLineDone ; A line feed ends the line. A is still the character.
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INIB 0xFF
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CCF
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SUB
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BRQ readLineEnd ; There is no more to be had.
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; Is there room for it? A still holds the character, so it is put somewhere safe while
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; the counting is done.
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SETD.1 ConsoleChar
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STA.1
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SETD.1 ConsoleLength
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LDA.1
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SETD.1 ConsoleRoom
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LDB.1
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CCF
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SUB
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BRQ readLineNext ; Full. Read on, and drop what comes.
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SETD.1 ConsoleChar
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LDA.1
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STA.0
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INCD.0
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SETD.1 ConsoleLength
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LDA.1
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INCA
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STA.1
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BRI readLineNext
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readLineEnd:
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SETD.1 ConsoleEndOfInput
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INIA 0x01
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STA.1
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readLineDone:
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RSTA
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STA.0 ; The zero byte that ends it.
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SETD.1 ConsoleLength
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LDA.1
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RSTB
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CCF
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ADD ; Q is how long the line is.
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RET
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#Data
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; ---- What readLine keeps while it works ----
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ConsoleRoom:
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0x00
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ConsoleLength:
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0x00
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ConsoleChar:
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0x00
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; Set when the console ran out rather than ending a line. Cleared at the start of every
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; readLine, so it always describes the last line read.
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ConsoleEndOfInput:
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0x00
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; ---- What the number routines keep while they work ----
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; Whether any digit has been printed yet, which is what decides if a zero is a leading
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; one or a real one.
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ConsoleLeading:
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0x00
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ConsoleCount:
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0x00
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ConsoleValue:
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0x00
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ConsoleBytePower:
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0x00
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ConsolePower:
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0x00 0x00
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ConsoleWord:
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0x00 0x00
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ConsoleSpare:
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0x00 0x00
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; The powers of ten, written the way every number here is written: most significant byte
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; first.
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ConsoleTenThousand:
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0x27 0x10
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ConsoleThousand:
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0x03 0xE8
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ConsoleHundred:
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0x00 0x64
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ConsoleTen:
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0x00 0x0A
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@@ -0,0 +1,781 @@
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; cosmos.asm
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; CosmOS, and the shell that is most of it.
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;
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; The machine boots into this. It registers what the hardware brought, mounts whatever
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; disk is attached, and then reads lines and does what they say until there is no more
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; typing to be had.
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;
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; ---- Where things live ----
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;
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; The system keeps to the bottom of both memories, and everything above is for whatever
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; it is running:
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;
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; Program Memory 0x0000 - 0x1FFF the system
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; 0x2000 - a loaded program's code
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; Data Memory 0x0000 - 0x0FFF the system
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; 0x1000 - a loaded program's data
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;
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; Nothing enforces that. Nothing can: the fence guards a range, and this is a convention
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; about which range belongs to whom rather than a rule about what may be touched. The
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; assembler prints both segment sizes, and they are what to watch.
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;
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; A program is staged at 0x8000 while it is being loaded, which is inside the region a
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; loaded program will own. That is safe because nothing is running during a load, and it
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; is where a big program can be read without the system reserving the room for good.
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;
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; ---- What it can do ----
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;
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; dir List what is on the disk.
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; load Read a program off the disk and put it where it asks to go.
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; run Start the program that was loaded.
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; help Say what these are.
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; exit Stop.
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;
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; dump is next. The dispatch below is a chain of comparisons, which is the right shape for
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; five commands and the wrong shape for twenty; when it grows, the table that
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; dispatchTest.asm demonstrates is where it should go.
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;
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; Written by Anachronaut
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#Include console.asm
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#Include text.asm
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#Include sbfs.asm
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#Include services.asm
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#Program
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boot:
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SETD.0 Banner
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CALL printString
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CALL newLine
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; Find out whether there is a filesystem to talk to. Doing this once at boot rather than
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; once per command means a disk swapped underneath us is not noticed, which is honest
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; for a machine whose disk is a file named on the command line.
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CALL sbfsMount
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SETD.0 DiskReady
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BNQ bootNoDisk
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INIA 0x01
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STA.0
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BRI prompt
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bootNoDisk:
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RSTA
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STA.0
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SETD.0 NoDisk
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CALL printString
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CALL newLine
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; ---- The loop ----
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prompt:
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SETD.0 PromptText
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CALL printString
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SETD.0 CommandLine
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INIB 0d63
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CALL readLine
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; Running out of typing is how this ends. It is not the same as an empty line, which is
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; just somebody pressing return, and the shell should sit there when that happens.
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SETD.0 ConsoleEndOfInput
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LDA.0
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BNA quitRanOut
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SETD.0 CommandLine
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CALL textSplit
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; An empty line asks for nothing.
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SETD.0 CommandLine
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LDA.0
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BRA prompt
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SETD.0 CommandLine
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SETD.1 DirName
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CALL textSame
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BRQ doDir
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SETD.0 CommandLine
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SETD.1 LoadName
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CALL textSame
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BRQ doLoad
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SETD.0 CommandLine
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SETD.1 RunName
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CALL textSame
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BRQ doRun
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SETD.0 CommandLine
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SETD.1 DumpName
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CALL textSame
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BRQ doDump
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SETD.0 CommandLine
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SETD.1 HelpName
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CALL textSame
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BRQ doHelp
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SETD.0 CommandLine
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SETD.1 ExitName
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CALL textSame
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BRQ quit
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; Nothing matched. Saying which word was not understood is worth the four instructions:
|
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; it tells somebody who mistyped what they actually typed.
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SETD.0 Unknown
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CALL printString
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SETD.0 CommandLine
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CALL printString
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CALL newLine
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BRI prompt
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||||
|
||||
; Running out of console leaves the cursor part way along a line, because there was no
|
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; return at the end to move it on. Somebody who typed "exit" has already pressed one, and
|
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; a second would only leave a blank line behind.
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quitRanOut:
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CALL newLine
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quit:
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SETD.0 Farewell
|
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CALL printString
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||||
CALL newLine
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||||
HALT
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||||
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||||
; ---- dir ----
|
||||
;
|
||||
; Walks the directory and prints what is in it. A free entry in the middle of a directory
|
||||
; is stepped over by the walk, so what comes out is the files and nothing else.
|
||||
|
||||
doDir:
|
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SETD.0 DiskReady
|
||||
LDA.0
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||||
BRA dirNoDisk
|
||||
|
||||
RSTA
|
||||
SETD.0 DirSeen
|
||||
STA.0
|
||||
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||||
CALL sbfsFirst
|
||||
BRI dirCheck
|
||||
dirStep:
|
||||
CALL sbfsNext
|
||||
dirCheck:
|
||||
BNQ dirDone
|
||||
|
||||
SETD.0 DirSeen
|
||||
LDA.0
|
||||
INCA
|
||||
STA.0
|
||||
|
||||
SETD.0 SbfsName
|
||||
CALL printString
|
||||
|
||||
SETD.0 SbfsName
|
||||
CALL nameWidth
|
||||
MVQA
|
||||
CALL printSpaces
|
||||
|
||||
; A file's length is its block count times 256 plus its tail, which is the block count
|
||||
; in the high byte and the tail in the low one. Nothing has to multiply anything.
|
||||
SETD.0 SbfsFileBlocks
|
||||
DPUP.0 0d01
|
||||
LDA.0
|
||||
SETD.1 DirSize
|
||||
STA.1
|
||||
SETD.0 SbfsFileTail
|
||||
LDA.0
|
||||
SETD.1 DirSize
|
||||
INCD.1
|
||||
STA.1
|
||||
|
||||
SETD.0 DirSize
|
||||
CALL printWordDecimal
|
||||
CALL newLine
|
||||
BRI dirStep
|
||||
|
||||
dirDone:
|
||||
SETD.0 DirSeen
|
||||
LDA.0
|
||||
CALL printByteDecimal
|
||||
SETD.0 FilesText
|
||||
CALL printString
|
||||
CALL newLine
|
||||
BRI prompt
|
||||
|
||||
dirNoDisk:
|
||||
SETD.0 NoDisk
|
||||
CALL printString
|
||||
CALL newLine
|
||||
BRI prompt
|
||||
|
||||
; DP0 names a string. Q is how many spaces pad it out to twenty four columns. A name
|
||||
; already that long gets one space, so that it cannot run into the number after it.
|
||||
nameWidth:
|
||||
INIA 0d24
|
||||
SETD.1 WidthLeft
|
||||
STA.1
|
||||
widthLoop:
|
||||
LDA.0
|
||||
BRA widthDone
|
||||
SETD.1 WidthLeft
|
||||
LDA.1
|
||||
DECA
|
||||
STA.1
|
||||
BRA widthFloor
|
||||
INCD.0
|
||||
BRI widthLoop
|
||||
widthFloor:
|
||||
INIA 0d1
|
||||
SETD.1 WidthLeft
|
||||
STA.1
|
||||
widthDone:
|
||||
SETD.1 WidthLeft
|
||||
LDA.1
|
||||
RSTB
|
||||
CCF
|
||||
ADD
|
||||
RET
|
||||
|
||||
; ---- load ----
|
||||
;
|
||||
; Reads a program off the disk and puts it where its header asks to go. Nothing relocates
|
||||
; anything: the addresses in the header are the ones the program was built for, and it
|
||||
; would not work anywhere else.
|
||||
;
|
||||
; The whole file is staged at 0x8000 first and then blitted into place, because where the
|
||||
; pieces belong is not known until the header has been read, and the header is in the file.
|
||||
|
||||
doLoad:
|
||||
SETD.0 DiskReady
|
||||
LDA.0
|
||||
BRA loadNoDisk
|
||||
|
||||
SETD.1 TextRest
|
||||
LDD.0.1
|
||||
LDA.0
|
||||
BRA loadNothingNamed
|
||||
|
||||
CALL sbfsFind
|
||||
BNQ loadMissing
|
||||
|
||||
SETD.1 0x80 0x00
|
||||
CALL sbfsRead
|
||||
BNQ loadUnreadable
|
||||
|
||||
; "SBEX", or this is not a program. Without this, loading a text file would put nonsense
|
||||
; into Program Memory and then jump into the middle of it.
|
||||
SETD.0 0x80 0x00
|
||||
SETD.2 ExecMagic
|
||||
INIA 0d4
|
||||
SETD.1 LoadCount
|
||||
STA.1
|
||||
loadMagicLoop:
|
||||
LDA.0
|
||||
LDB.2
|
||||
XOR
|
||||
BNQ loadNotProgram
|
||||
INCD.0
|
||||
INCD.2
|
||||
LDA.1
|
||||
DECA
|
||||
STA.1
|
||||
BNA loadMagicLoop
|
||||
|
||||
SETD.0 0x80 0x00
|
||||
DPUP.0 0d04
|
||||
LDA.0
|
||||
INIB 0d1
|
||||
XOR
|
||||
BNQ loadWrongVersion
|
||||
|
||||
; The code. It comes from the staging area just past the sixteen byte header, and goes
|
||||
; wherever the header says, in Program Memory, which the instruction set cannot write
|
||||
; and the controller can.
|
||||
INIA 0d1
|
||||
OUTA 0xE0 ; SourceBank: Data Memory, where the file was staged.
|
||||
INIA 0x80
|
||||
OUTA 0xE1
|
||||
INIA 0d16
|
||||
OUTA 0xE2 ; 0x8010, the first byte after the header.
|
||||
|
||||
RSTA
|
||||
OUTA 0xE3 ; DestBank: Program Memory.
|
||||
SETD.0 0x80 0x00
|
||||
DPUP.0 0d06
|
||||
LDA.0
|
||||
OUTA 0xE4
|
||||
INCD.0
|
||||
LDA.0
|
||||
OUTA 0xE5
|
||||
|
||||
SETD.0 0x80 0x00
|
||||
DPUP.0 0d10
|
||||
LDA.0
|
||||
OUTA 0xE6
|
||||
INCD.0
|
||||
LDA.0
|
||||
OUTA 0xE7
|
||||
|
||||
INIA 0x01
|
||||
OUTA 0xE8 ; Blit.
|
||||
|
||||
; Then the data. A blit leaves its addresses past whatever it touched, so the source is
|
||||
; already sitting on the first byte of the data and only the destination changes.
|
||||
INIA 0d1
|
||||
OUTA 0xE3 ; DestBank: Data Memory.
|
||||
SETD.0 0x80 0x00
|
||||
DPUP.0 0d12
|
||||
LDA.0
|
||||
OUTA 0xE4
|
||||
INCD.0
|
||||
LDA.0
|
||||
OUTA 0xE5
|
||||
|
||||
SETD.0 0x80 0x00
|
||||
DPUP.0 0d14
|
||||
LDA.0
|
||||
OUTA 0xE6
|
||||
INCD.0
|
||||
LDA.0
|
||||
OUTA 0xE7
|
||||
|
||||
INIA 0x01
|
||||
OUTA 0xE8 ; Blit.
|
||||
|
||||
; Where it starts. Written out by hand rather than through a routine, because a routine
|
||||
; could not hand two bytes back: CALL puts A, B and the first three pointers back the
|
||||
; way it found them.
|
||||
SETD.0 0x80 0x00
|
||||
DPUP.0 0d08
|
||||
LDA.0
|
||||
SETD.1 LoadedEntry
|
||||
STA.1
|
||||
INCD.0
|
||||
INCD.1
|
||||
LDA.0
|
||||
STA.1
|
||||
|
||||
INIA 0x01
|
||||
SETD.0 LoadedOk
|
||||
STA.0
|
||||
|
||||
SETD.0 LoadedText
|
||||
CALL printString
|
||||
SETD.0 LoadedEntry
|
||||
CALL printWordHex
|
||||
CALL newLine
|
||||
BRI prompt
|
||||
|
||||
loadNoDisk:
|
||||
SETD.0 NoDisk
|
||||
BRI loadComplain
|
||||
loadNothingNamed:
|
||||
SETD.0 LoadWhat
|
||||
BRI loadComplain
|
||||
loadMissing:
|
||||
SETD.0 NoSuchFile
|
||||
BRI loadComplain
|
||||
loadUnreadable:
|
||||
SETD.0 Unreadable
|
||||
BRI loadComplain
|
||||
loadNotProgram:
|
||||
SETD.0 NotProgram
|
||||
BRI loadComplain
|
||||
loadWrongVersion:
|
||||
SETD.0 WrongVersion
|
||||
loadComplain:
|
||||
CALL printString
|
||||
CALL newLine
|
||||
BRI prompt
|
||||
|
||||
; ---- run ----
|
||||
;
|
||||
; Hands the machine to whatever was loaded. Where the Stack is now is written down first,
|
||||
; because the program is not going to unwind anything it pushes and the exit handler has
|
||||
; to be able to put the Stack back.
|
||||
|
||||
doRun:
|
||||
SETD.0 LoadedOk
|
||||
LDA.0
|
||||
BRA runNothing
|
||||
|
||||
MVSD.0
|
||||
SETD.1 SystemStack
|
||||
STD.0.1
|
||||
|
||||
; The entry address is a number until BRD makes it a place. DP3 is the one to build it
|
||||
; in, because it is the pointer nothing puts back.
|
||||
SETD.1 LoadedEntry
|
||||
LDD.3.1
|
||||
BRD.3
|
||||
|
||||
runNothing:
|
||||
SETD.0 NothingLoaded
|
||||
CALL printString
|
||||
CALL newLine
|
||||
BRI prompt
|
||||
|
||||
; ---- The services ----
|
||||
;
|
||||
; These are what a loaded program is allowed to ask for. The names and their numbers come
|
||||
; from services.asm, which the programs include as well, so neither side writes a number
|
||||
; down and the two cannot disagree about them.
|
||||
;
|
||||
; A handler arrives with the caller's registers exactly as they were: an interrupt frame
|
||||
; is pushed, not cleared. So the pointer a program put in DP0 is still there to be used.
|
||||
|
||||
handlePrintString:
|
||||
CALL printString
|
||||
RETI
|
||||
|
||||
handleReadLine:
|
||||
CALL readLine
|
||||
RETI
|
||||
|
||||
; Giving the machine back. This is the one place MVDS earns its keep. The program's Stack,
|
||||
; and the frame this very interrupt arrived on, are both abandoned where they lie, because
|
||||
; nothing is going to return through either of them.
|
||||
;
|
||||
; Which is exactly why this cannot RETI. Its return address is on the Stack it just walked
|
||||
; away from, so it branches to the prompt instead.
|
||||
handleExit:
|
||||
SETD.1 SystemStack
|
||||
LDD.0.1
|
||||
MVDS.0
|
||||
|
||||
; The console goes back to line mode whatever the program left it in. A program that
|
||||
; wanted keys is expected to put it back itself, but one that stopped early, or forgot,
|
||||
; would otherwise hand back a shell with no echo and no backspace, and the shell has no
|
||||
; way to find out that happened. Writing line mode when it is already in line mode costs
|
||||
; a byte out of a port and does nothing, which is the right price for not having to know.
|
||||
RSTA
|
||||
OUTA 0x02
|
||||
|
||||
SETD.0 Finished
|
||||
CALL printString
|
||||
CALL newLine
|
||||
BRI prompt
|
||||
|
||||
; ---- dump ----
|
||||
;
|
||||
; dump Sixty four more bytes, carrying on from the last one.
|
||||
; dump <where> From the start of that bank.
|
||||
; dump <where> <addr> From there.
|
||||
;
|
||||
; <where> is program, data, or a bank number in hexadecimal. That the CPU cannot read
|
||||
; Program Memory and this can is the whole point: the instruction set has no way to look
|
||||
; at itself, and the controller does, so a monitor is possible at all only through it.
|
||||
|
||||
doDump:
|
||||
SETD.1 TextRest
|
||||
LDD.0.1
|
||||
LDA.0
|
||||
BRA dumpGo ; Nothing said, so carry on from where the last one stopped.
|
||||
|
||||
; Which bank. The two that always exist have names, because typing "program" is what
|
||||
; somebody means and 0 is what the machine calls it.
|
||||
CALL textSplit
|
||||
SETD.1 ProgramWord
|
||||
CALL textSame
|
||||
BRQ dumpBankProgram
|
||||
SETD.1 DataWord
|
||||
CALL textSame
|
||||
BRQ dumpBankData
|
||||
|
||||
CALL textHexWord
|
||||
BNQ dumpBadWhere
|
||||
SETD.0 TextValue
|
||||
INCD.0
|
||||
LDA.0
|
||||
BRI dumpSetBank
|
||||
dumpBankProgram:
|
||||
RSTA
|
||||
BRI dumpSetBank
|
||||
dumpBankData:
|
||||
INIA 0d1
|
||||
dumpSetBank:
|
||||
SETD.0 DumpBank
|
||||
STA.0
|
||||
|
||||
; And where in it. Naming a bank without an address means the start of it, which is the
|
||||
; only answer that does not depend on what was asked for last time.
|
||||
RSTA
|
||||
SETD.0 DumpAt
|
||||
STA.0
|
||||
INCD.0
|
||||
STA.0
|
||||
|
||||
SETD.1 TextRest
|
||||
LDD.0.1
|
||||
LDA.0
|
||||
BRA dumpCheckBank
|
||||
CALL textHexWord
|
||||
BNQ dumpBadWhere
|
||||
SETD.0 TextValue
|
||||
LDA.0
|
||||
SETD.1 DumpAt
|
||||
STA.1
|
||||
SETD.0 TextValue
|
||||
INCD.0
|
||||
LDA.0
|
||||
SETD.1 DumpAt
|
||||
INCD.1
|
||||
STA.1
|
||||
|
||||
dumpCheckBank:
|
||||
; Is there such a bank? Asking the controller for a bank that is not there is refused,
|
||||
; and a refusal nobody catches stops the machine, which is a poor answer to a typing
|
||||
; mistake. The bank table says what exists, and it lives in bank 2.
|
||||
;
|
||||
; Bank n's record starts at n times eight. A and B are a shift register sixteen bits
|
||||
; wide, so putting the number in the low half and rotating left three times multiplies
|
||||
; it by eight without anything falling off the top: the most it can reach is 2040.
|
||||
RSTA
|
||||
SETD.0 DumpBank
|
||||
LDB.0
|
||||
SHL SHL SHL
|
||||
SETD.0 DumpRecord
|
||||
STA.0
|
||||
INCD.0
|
||||
STB.0
|
||||
|
||||
INIA 0d2
|
||||
OUTA 0xE0 ; SourceBank: the controller's own memory.
|
||||
SETD.0 DumpRecord
|
||||
LDA.0
|
||||
OUTA 0xE1
|
||||
INCD.0
|
||||
LDA.0
|
||||
OUTA 0xE2
|
||||
INA 0xE9 ; The flags byte of that bank's record.
|
||||
INIB 0x01
|
||||
AND
|
||||
BRQ dumpNoBank ; The present bit is down, so nothing is there.
|
||||
|
||||
dumpGo:
|
||||
INIA 0d4
|
||||
SETD.0 DumpRows
|
||||
STA.0
|
||||
|
||||
dumpRow:
|
||||
SETD.0 DumpAt
|
||||
CALL printWordHex
|
||||
INIA 0d2
|
||||
CALL printSpaces
|
||||
|
||||
; Point the controller at the row. Reading the Data port takes a byte and steps the
|
||||
; source on, so the whole row is one instruction repeated.
|
||||
SETD.0 DumpBank
|
||||
LDA.0
|
||||
OUTA 0xE0
|
||||
SETD.0 DumpAt
|
||||
LDA.0
|
||||
OUTA 0xE1
|
||||
INCD.0
|
||||
LDA.0
|
||||
OUTA 0xE2
|
||||
|
||||
; Sixteen bytes, kept as they go past so that they can be shown twice.
|
||||
INIA 0d16
|
||||
SETD.0 DumpCount
|
||||
STA.0
|
||||
SETD.1 DumpBytes
|
||||
dumpByte:
|
||||
INA 0xE9
|
||||
STA.1
|
||||
CALL printByteHex
|
||||
INIA 0x20
|
||||
OUTA 0x00
|
||||
INCD.1
|
||||
SETD.0 DumpCount
|
||||
LDA.0
|
||||
DECA
|
||||
STA.0
|
||||
BNA dumpByte
|
||||
|
||||
; The same sixteen again, as characters. Anything that is not printable shows as a dot,
|
||||
; because a control character sent to the console would move the cursor and ruin the
|
||||
; shape of the dump.
|
||||
INIA 0x20
|
||||
OUTA 0x00
|
||||
INIA 0d16
|
||||
SETD.0 DumpCount
|
||||
STA.0
|
||||
SETD.1 DumpBytes
|
||||
dumpChar:
|
||||
LDA.1
|
||||
INIB 0x20
|
||||
CCF
|
||||
SUB
|
||||
BRC dumpDot ; Below a space.
|
||||
INIB 0x7F
|
||||
CCF
|
||||
SUB
|
||||
BNC dumpDot ; Delete, or above it.
|
||||
OUTA 0x00
|
||||
BRI dumpCharNext
|
||||
dumpDot:
|
||||
INIA 0x2E
|
||||
OUTA 0x00
|
||||
dumpCharNext:
|
||||
INCD.1
|
||||
SETD.0 DumpCount
|
||||
LDA.0
|
||||
DECA
|
||||
STA.0
|
||||
BNA dumpChar
|
||||
CALL newLine
|
||||
|
||||
; Sixteen further along, carrying into the high byte if the low one wrapped.
|
||||
SETD.0 DumpAt
|
||||
INCD.0
|
||||
LDA.0
|
||||
INIB 0d16
|
||||
CCF
|
||||
ADD
|
||||
STQ.0
|
||||
BNC dumpRowNext
|
||||
SETD.0 DumpAt
|
||||
LDA.0
|
||||
INCA
|
||||
STA.0
|
||||
dumpRowNext:
|
||||
SETD.0 DumpRows
|
||||
LDA.0
|
||||
DECA
|
||||
STA.0
|
||||
BNA dumpRow
|
||||
BRI prompt
|
||||
|
||||
dumpBadWhere:
|
||||
SETD.0 DumpUsage
|
||||
CALL printString
|
||||
CALL newLine
|
||||
BRI prompt
|
||||
dumpNoBank:
|
||||
SETD.0 NoSuchBank
|
||||
CALL printString
|
||||
CALL newLine
|
||||
BRI prompt
|
||||
|
||||
; ---- help ----
|
||||
|
||||
doHelp:
|
||||
SETD.0 HelpText
|
||||
CALL printString
|
||||
CALL newLine
|
||||
SETD.0 HelpMoreText
|
||||
CALL printString
|
||||
CALL newLine
|
||||
BRI prompt
|
||||
|
||||
#Data
|
||||
|
||||
Banner:
|
||||
"CosmOS"
|
||||
PromptText:
|
||||
"> "
|
||||
NoDisk:
|
||||
"no filesystem on the disk"
|
||||
Unknown:
|
||||
"I do not know: "
|
||||
Farewell:
|
||||
"halted"
|
||||
FilesText:
|
||||
" files"
|
||||
|
||||
; Two strings rather than one, because a string literal stops at 255 characters and each
|
||||
; one carries its own zero byte, so they are printed in turn rather than joined.
|
||||
HelpText:
|
||||
"dir list what is on the disk
|
||||
load <file> read a program off the disk
|
||||
run start what was loaded"
|
||||
HelpMoreText:
|
||||
"dump sixty four bytes of memory, and again for more
|
||||
dump <program|data|bank> <address>
|
||||
help this
|
||||
exit stop"
|
||||
|
||||
DumpUsage:
|
||||
"dump <program|data|bank> <address>"
|
||||
NoSuchBank:
|
||||
"there is no such bank"
|
||||
ProgramWord:
|
||||
"program"
|
||||
DataWord:
|
||||
"data"
|
||||
DumpName:
|
||||
"dump"
|
||||
|
||||
ExecMagic:
|
||||
"SBEX"
|
||||
LoadWhat:
|
||||
"load what?"
|
||||
NoSuchFile:
|
||||
"no such file"
|
||||
Unreadable:
|
||||
"could not read it"
|
||||
NotProgram:
|
||||
"not a program"
|
||||
WrongVersion:
|
||||
"a version I do not know"
|
||||
LoadedText:
|
||||
"loaded, starting at "
|
||||
NothingLoaded:
|
||||
"nothing is loaded"
|
||||
Finished:
|
||||
"finished"
|
||||
|
||||
DirName:
|
||||
"dir"
|
||||
LoadName:
|
||||
"load"
|
||||
RunName:
|
||||
"run"
|
||||
HelpName:
|
||||
"help"
|
||||
ExitName:
|
||||
"exit"
|
||||
|
||||
DiskReady:
|
||||
0x00
|
||||
LoadedOk:
|
||||
0x00
|
||||
LoadedEntry:
|
||||
0x00 0x00
|
||||
LoadCount:
|
||||
0x00
|
||||
|
||||
; Where the monitor is looking, so that a bare 'dump' can carry on from it.
|
||||
DumpBank:
|
||||
0x00
|
||||
DumpAt:
|
||||
0x00 0x00
|
||||
DumpRows:
|
||||
0x00
|
||||
DumpCount:
|
||||
0x00
|
||||
DumpRecord:
|
||||
0x00 0x00
|
||||
DumpBytes:
|
||||
#Reserve 0d16
|
||||
|
||||
; Where the system's Stack was when it handed the machine to a program. Kept below the
|
||||
; region a program owns, so that a program has to go looking to break it.
|
||||
SystemStack:
|
||||
0x00 0x00
|
||||
DirSeen:
|
||||
0x00
|
||||
DirSize:
|
||||
0x00 0x00
|
||||
WidthLeft:
|
||||
0x00
|
||||
|
||||
; Sixty three characters and the zero byte that ends them.
|
||||
CommandLine:
|
||||
#Reserve 0d64
|
||||
|
||||
#Vectors
|
||||
|
||||
Boot boot
|
||||
osPrintString handlePrintString
|
||||
osReadLine handleReadLine
|
||||
osExit handleExit
|
||||
File diff suppressed because it is too large
Load Diff
@@ -0,0 +1,19 @@
|
||||
; The services the system offers, named and numbered.
|
||||
;
|
||||
; Both sides include this. The system follows it with handlers for the ones it implements.
|
||||
; A program that only calls them includes this and nothing else, and can then say them by
|
||||
; name, because a line with a name and nothing after it declares what a vector is called
|
||||
; and what number it has without claiming to implement it.
|
||||
;
|
||||
; The order here is what fixes the numbers, and it is fixed in one file, so the two sides
|
||||
; cannot disagree about them and nobody has to write a number down. Adding a service goes
|
||||
; at the end: putting one in the middle would renumber everything after it, and any
|
||||
; program already assembled against the old numbers would call the wrong thing.
|
||||
;
|
||||
; Written by Anachronaut
|
||||
|
||||
#Vectors
|
||||
|
||||
osPrintString ; DP0 names a string. Prints it.
|
||||
osReadLine ; DP0 names somewhere to put a line read from the console.
|
||||
osExit ; Give the machine back to the system.
|
||||
@@ -0,0 +1,230 @@
|
||||
; text.asm
|
||||
; Picking a line of typing apart.
|
||||
;
|
||||
; A shell reads a line and has to decide what was asked for. That is two jobs: cutting the
|
||||
; first word off the line, and telling whether a word is the one being looked for. There
|
||||
; is nothing else here, because there is nothing else a command line needs yet.
|
||||
;
|
||||
; Written by Anachronaut
|
||||
|
||||
#Program
|
||||
|
||||
; DP0 names a line ending in a zero byte. Cuts the first word off it, in place, by writing
|
||||
; a zero byte over the space that ends the word. DP0 is unchanged, because a RET puts it
|
||||
; back, so afterwards DP0 names just the first word.
|
||||
;
|
||||
; Where the rest of the line begins goes in TextRest, with any spaces between skipped. A
|
||||
; line with only one word on it leaves TextRest naming that line's zero byte, which reads
|
||||
; as an empty argument rather than as a missing one, and is the same thing here.
|
||||
textSplit:
|
||||
LDA.0
|
||||
BRA textSplitHere ; The line ended, so the whole of it was one word.
|
||||
INIB 0x20
|
||||
CCF
|
||||
SUB
|
||||
BRQ textSplitCut
|
||||
INCD.0
|
||||
BRI textSplit
|
||||
|
||||
textSplitCut:
|
||||
RSTA
|
||||
STA.0 ; The space becomes the end of the word.
|
||||
INCD.0
|
||||
|
||||
textSplitSkip:
|
||||
LDA.0
|
||||
BRA textSplitHere
|
||||
INIB 0x20
|
||||
CCF
|
||||
SUB
|
||||
BNQ textSplitHere ; Something that is not a space: the rest starts here.
|
||||
INCD.0
|
||||
BRI textSplitSkip
|
||||
|
||||
textSplitHere:
|
||||
SETD.1 TextRest
|
||||
STD.0.1
|
||||
RET
|
||||
|
||||
; DP0 and DP1 name strings ending in zero bytes. Q is zero if they are the same.
|
||||
;
|
||||
; The two ending together is what makes them the same. Comparing until one of them ends
|
||||
; would call "dir" and "dirty" the same word, which is the kind of thing a shell gets
|
||||
; wrong once and confusingly.
|
||||
textSame:
|
||||
LDA.0
|
||||
LDB.1
|
||||
CCF
|
||||
SUB
|
||||
BNQ textDiffer
|
||||
LDA.0
|
||||
BRA textAlike ; Equal, and both of them zero: they ended together.
|
||||
INCD.0
|
||||
INCD.1
|
||||
BRI textSame
|
||||
|
||||
textAlike:
|
||||
RSTA
|
||||
RSTB
|
||||
CCF
|
||||
ADD ; Q is zero: the same.
|
||||
RET
|
||||
|
||||
textDiffer:
|
||||
RSTA
|
||||
INIB 0d1
|
||||
CCF
|
||||
ADD ; Q is one: not the same.
|
||||
RET
|
||||
|
||||
; DP0 names text. Reads hexadecimal digits off the front of it into TextValue, most
|
||||
; significant byte first. Q is zero if there was at least one digit to read.
|
||||
;
|
||||
; Digits past the fourth push the earlier ones off the top rather than being refused,
|
||||
; which is what typing over an address does on every monitor there has ever been.
|
||||
textHexWord:
|
||||
RSTA
|
||||
SETD.1 TextValue
|
||||
STA.1
|
||||
INCD.1
|
||||
STA.1
|
||||
SETD.1 TextDigits
|
||||
STA.1
|
||||
|
||||
textHexLoop:
|
||||
LDA.0
|
||||
CALL textHexDigit
|
||||
PSHQ
|
||||
POPA
|
||||
INIB 0xFF
|
||||
CCF
|
||||
SUB
|
||||
BRQ textHexEnd ; Not a digit, so the number stopped before it.
|
||||
|
||||
CALL textHexShift
|
||||
SETD.1 TextDigits
|
||||
LDA.1
|
||||
INCA
|
||||
STA.1
|
||||
INCD.0
|
||||
BRI textHexLoop
|
||||
|
||||
textHexEnd:
|
||||
SETD.1 TextDigits
|
||||
LDA.1
|
||||
BRA textHexNothing
|
||||
RSTA
|
||||
RSTB
|
||||
CCF
|
||||
ADD ; Q is zero: there was a number.
|
||||
RET
|
||||
textHexNothing:
|
||||
RSTA
|
||||
INIB 0d1
|
||||
CCF
|
||||
ADD ; Q is one: there was not.
|
||||
RET
|
||||
|
||||
; A holds the digit just read. Moves TextValue up by one place and puts the digit in the
|
||||
; hole that leaves.
|
||||
;
|
||||
; A and B are a circular shift register sixteen bits long, so rotating them left four
|
||||
; times multiplies the pair by sixteen. What fell off the top of the high byte comes round
|
||||
; into the bottom of the low one, which is exactly the nybble the new digit wants, so it
|
||||
; is masked away first.
|
||||
textHexShift:
|
||||
SETD.1 TextDigit
|
||||
STA.1
|
||||
|
||||
SETD.0 TextValue
|
||||
LDA.0
|
||||
INCD.0
|
||||
LDB.0
|
||||
SHL SHL SHL SHL
|
||||
|
||||
SETD.0 TextValue
|
||||
STA.0 ; The high byte is finished.
|
||||
|
||||
PSHB
|
||||
POPA
|
||||
INIB 0xF0
|
||||
AND
|
||||
MVQA
|
||||
SETD.1 TextDigit
|
||||
LDB.1
|
||||
OR
|
||||
SETD.0 TextValue
|
||||
INCD.0
|
||||
STQ.0
|
||||
RET
|
||||
|
||||
; A holds a character. Q is what it is worth as a hexadecimal digit, or 0xFF if it is not
|
||||
; one. Upper and lower case both count, because nobody wants to be told which they meant.
|
||||
;
|
||||
; Everything below works from the distance above '0', which is why the letters are tested
|
||||
; at seventeen and thirty two rather than at anything recognisable.
|
||||
textHexDigit:
|
||||
INIB 0x30
|
||||
CCF
|
||||
SUB
|
||||
BRC textHexNo ; Below '0'.
|
||||
MVQA
|
||||
INIB 0d10
|
||||
CCF
|
||||
SUB
|
||||
BNC textHexUpper ; Ten or more above '0', so not 0 to 9.
|
||||
RSTB
|
||||
CCF
|
||||
ADD ; Q is the digit itself.
|
||||
RET
|
||||
|
||||
textHexUpper:
|
||||
INIB 0d17
|
||||
CCF
|
||||
SUB
|
||||
BRC textHexNo ; Between '9' and 'A'.
|
||||
MVQA
|
||||
INIB 0d6
|
||||
CCF
|
||||
SUB
|
||||
BNC textHexLower ; Past 'F'.
|
||||
INIB 0d10
|
||||
CCF
|
||||
ADD
|
||||
RET
|
||||
|
||||
textHexLower:
|
||||
INIB 0d32
|
||||
CCF
|
||||
SUB
|
||||
BRC textHexNo ; Between 'F' and 'a'.
|
||||
MVQA
|
||||
INIB 0d6
|
||||
CCF
|
||||
SUB
|
||||
BNC textHexNo ; Past 'f'.
|
||||
INIB 0d10
|
||||
CCF
|
||||
ADD
|
||||
RET
|
||||
|
||||
textHexNo:
|
||||
RSTA
|
||||
INIB 0xFF
|
||||
CCF
|
||||
ADD
|
||||
RET
|
||||
|
||||
#Data
|
||||
|
||||
; Where the rest of the line begins, after textSplit has taken a word off the front.
|
||||
TextRest:
|
||||
0x00 0x00
|
||||
|
||||
; What textHexWord read, and what it needs while reading it.
|
||||
TextValue:
|
||||
0x00 0x00
|
||||
TextDigits:
|
||||
0x00
|
||||
TextDigit:
|
||||
0x00
|
||||
Reference in New Issue
Block a user