141 lines
3.0 KiB
NASM
141 lines
3.0 KiB
NASM
; Exercises the console's status and control ports.
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;
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; The console answers on three ports now: 0x00 for bytes as it always did, 0x01 for what
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; it is doing, and 0x02 to say which mode it should be in. The point of the mode is that
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; the data port never changed, so this checks the old behaviour is still there as much as
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; it checks the new behaviour arrived.
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;
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; What the status bits mean:
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; bit 0 READY reading the data port will not have to wait
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; bit 1 ENDED input has run out for good
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; bit 2 KEYMODE the console is in key mode
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;
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; This runs with input from a file rather than a terminal, so key mode has no terminal to
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; put into another state and the mode bit is the only thing that changes. That is on
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; purpose: the same program has to work either way, and a test that needed a terminal
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; could not run here at all.
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#Include console.asm
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#Program
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start:
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SETD.0 Banner
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CALL printString
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CALL newLine
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; ---- What mode does it start in ----
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;
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; Nothing has been written to the control port, so this is how the machine comes up, and
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; every program written before these ports existed runs in exactly this.
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SETD.0 AtStartLabel
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CALL printString
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CALL showStatus
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; ---- Into key mode ----
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INIA 0x01
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OUTA 0x02
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SETD.0 KeyModeLabel
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CALL printString
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CALL showStatus
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; ---- Read what is waiting ----
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;
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; Reading until ENDED rather than until a count, which is the thing that could not be
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; done before: 0xFF from the data port used to mean both "the byte 0xFF" and "there is
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; no more", and nothing could tell those apart.
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SETD.0 ReadLabel
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CALL printString
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CALL newLine
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readLoop:
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INA 0x01
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INIB 0x02 ; ENDED
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AND
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BNQ readDone
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INA 0x00
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OUTA 0x00 ; Nothing echoes in key mode, so the program does it.
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BRI readLoop
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readDone:
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CALL newLine
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; ---- The status at the end of input ----
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;
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; READY is set as well as ENDED, because a read does answer at once. It just answers
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; 0xFF forever. ENDED is what says so.
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SETD.0 AtEndLabel
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CALL printString
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CALL showStatus
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; ---- Back to line mode ----
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RSTA
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OUTA 0x02
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SETD.0 LineModeLabel
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CALL printString
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CALL showStatus
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HALT
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; Prints the status byte as hex and then names the bits that are up, so that a change in
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; the output says which bit moved rather than only that the number is different.
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showStatus:
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INA 0x01
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PSHA
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CALL printByteHex
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INIA 0x20
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OUTA 0x00
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POPA
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PSHA
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INIB 0x01
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AND
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BRQ showNotReady
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SETD.0 ReadyWord
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CALL printString
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showNotReady:
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POPA
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PSHA
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INIB 0x02
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AND
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BRQ showNotEnded
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SETD.0 EndedWord
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CALL printString
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showNotEnded:
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POPA
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INIB 0x04
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AND
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BRQ showNotKeys
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SETD.0 KeysWord
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CALL printString
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showNotKeys:
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CALL newLine
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RET
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#Data
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Banner:
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"console mode ports"
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AtStartLabel:
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"at start: "
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KeyModeLabel:
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"key mode: "
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AtEndLabel:
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"at the end: "
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LineModeLabel:
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"line mode: "
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ReadLabel:
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"what came in:"
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ReadyWord:
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"ready "
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EndedWord:
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"ended "
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KeysWord:
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"keys "
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#Vectors
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Boot start
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