Anachronaut
87d819847e
SWI osExit takes a status in A, and the shell keeps it. Fifty eight exits across twenty three programs now say deliberately whether they worked: 25 did what they were asked, 24 did not, 9 were asked wrongly. Compare is the exception and says so - one there means the files differ, which is a result rather than a failure, the way diff has always had it. IN A RATHER THAN Q, which is not a departure from the rule that a service answers in Q. This one takes an ARGUMENT, the way osPrintNumber takes A and B, and it never returns to answer anything. A is free precisely because a return would have put it back - and Q is the ALU's output, so a small number costs four instructions there against one in A. The shell does not print it. A program that failed has already said so in words and a number beside that is noise, so osLastStatus hands it back and Status is the program that shows it. That indirection is the point: the number exists for the thing that cannot read words. MARKING THE EXITS FOUND A DEFECT ON THE FIRST RUN. Type and More printed why they had failed and then fell through into the success exit, reporting that all was well. Nobody had noticed, because while the only reader was a person, the person could see both the complaint and the claim. Two smaller things. Snake sets the console to line mode and then exits with zero, and the linter flagged the second RSTA as redundant - an exit status and a console mode, equal by accident, which is the class that must never be collapsed. And the README still taught answering by writing into the frame, three months of habit that SRET replaced yesterday; that section is gone and the one describing SRET stands in its place.
94 lines
2.2 KiB
NASM
94 lines
2.2 KiB
NASM
; Settle.asm
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; Says how the last start went, and tells the machine to stop falling back.
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;
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; A program rather than a shell command, because the shell is for the things you cannot do
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; without it and this is not one of them. It reaches the system through SWI like anything
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; else, which means it can be replaced, left off a disk, or called by whatever comes to
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; call programs in sequence - and none of that is true of a word built into the shell.
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;
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; ---- What settling means ----
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;
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; The loader marks the disk before handing over and the system clears the mark on reaching
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; its prompt, so a mark still set is a start that never arrived. After that the loader uses
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; the fallback and KEEPS USING IT, because a system known not to start should not be tried
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; every other boot for ever.
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;
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; Settling is how it is told that has changed. It does not fix anything and it does not
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; check anything: it says "the situation is different now, try again". Which is why it is a
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; deliberate act by somebody who has just changed something, rather than anything automatic.
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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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SWI osBootState
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MVQA
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SETD.0 State
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STA.0
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BRA alreadySettled
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INIB 0d2
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XOR
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BRQ fellBack
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; Trying. Nothing has gone wrong yet - this is what the disk looks like while a start is
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; still in progress, which from in here means the system that is running has not reached
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; its prompt, which it plainly has. So the mark is stale.
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SETD.0 WasTrying
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SWI osPrintString
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BRI doSettle
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fellBack:
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SETD.0 WasFallen
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SWI osPrintString
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doSettle:
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SWI osBootSettle
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MVQA
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BNA settleFailed
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SETD.0 Settled
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SWI osPrintString
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RSTA
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SWI osExit
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settleFailed:
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SETD.0 NoDisk
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SWI osPrintString
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INIA 0d1
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SWI osExit
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alreadySettled:
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SETD.0 Already
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SWI osPrintString
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RSTA
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SWI osExit
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#Data
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#Base 0x2000
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WasTrying:
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"the disk says a start is still in progress
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"
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WasFallen:
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"the disk says the last start did not arrive, so this is the fallback
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"
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Settled:
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"settled: the next start will use the configuration again
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"
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Already:
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"already settled: the next start will use the configuration
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"
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NoDisk:
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"nothing to settle: no disk answered
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"
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State:
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0x00
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