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.
285 lines
4.0 KiB
NASM
285 lines
4.0 KiB
NASM
; Compare two files without asking either one to fit in Data Memory.
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;
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; Each occupied block is read into its own 256-byte buffer. The byte count returned for
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; the block is compared before its contents, and only those bytes are examined: bytes
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; after the end of a short final block belong to neither file and are allowed to differ.
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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 0x4000
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start:
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SETD.0 Arguments
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INIB 0xFF
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SWI osArgument
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SETD.0 Arguments
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LDA.0
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BRA usage
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CALL textSplit
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SETD.0 TextRest
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LDD.0.0
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LDA.0
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BRA usage
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SETD.0 Arguments
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SWI osFileInfo
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BNQ firstFailed
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SETD.0 FirstBlocks
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STD.3.0
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SETD.0 TextRest
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LDD.0.0
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SWI osFileInfo
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BNQ secondFailed
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SETD.0 SecondBlocks
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STD.3.0
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; A different number of occupied blocks is immediately a different file.
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SETD.0 FirstBlocks
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LDA.0
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SETD.1 SecondBlocks
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LDB.1
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CCF
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SUB
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BNQ different
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INCD.0
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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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BNQ different
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SETD.0 FirstBlocks
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SETD.1 RemainingBlocks
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CALL copyWord
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RSTA
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SETD.0 Index
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STA.0
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INCD.0
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STA.0
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nextBlock:
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SETD.0 RemainingBlocks
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LDA.0
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INCD.0
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LDB.0
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OR
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BRQ alike
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SETD.0 Arguments
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SETD.1 FirstBlock
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CALL readAtIndex
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BNQ firstReadFailed
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SETD.0 FirstCount
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STD.3.0
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SETD.0 TextRest
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LDD.0.0
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SETD.1 SecondBlock
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CALL readAtIndex
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BNQ secondReadFailed
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SETD.0 SecondCount
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STD.3.0
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; Equal occupied-block counts do not imply equal tails, so compare the valid byte count
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; returned for this block as well.
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SETD.0 FirstCount
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LDA.0
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SETD.1 SecondCount
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LDB.1
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CCF
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SUB
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BNQ different
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INCD.0
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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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BNQ different
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SETD.0 FirstCount
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SETD.1 BytesLeft
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CALL copyWord
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SETD.0 FirstBlock
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SETD.1 SecondBlock
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compareByte:
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SETD.2 BytesLeft
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LDA.2
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INCD.2
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LDB.2
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OR
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BRQ blockSame
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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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BNQ different
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INCD.0
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INCD.1
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SETD.2 BytesLeft
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CALL takeByte
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BRI compareByte
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blockSame:
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CALL stepIndex
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CALL takeBlock
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BRI nextBlock
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; DP0 is the path and DP1 the destination buffer. Q and DP3 are the service answers.
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readAtIndex:
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SETD.2 Index
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LDA.2
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INCD.2
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LDB.2
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SWI osFileBlock
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RET
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; DP0 names the source word and DP1 the destination word.
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copyWord:
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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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stepIndex:
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SETD.0 Index
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INCD.0
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LDA.0
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INCA
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STA.0
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BNC stepDone
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DECD.0
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LDA.0
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INCA
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STA.0
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stepDone:
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RET
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takeBlock:
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SETD.0 RemainingBlocks
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INCD.0
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LDA.0
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BRA blockBorrow
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DECA
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STA.0
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RET
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blockBorrow:
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INIA 0xFF
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STA.0
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DECD.0
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LDA.0
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DECA
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STA.0
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RET
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; Decrement the big-endian sixteen-bit BytesLeft. A full block arrives as 0x0100, so an
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; eight-bit counter would compare none of it and call many different files equal.
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takeByte:
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INCD.2
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LDA.2
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BRA byteBorrow
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DECA
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STA.2
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RET
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byteBorrow:
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INIA 0xFF
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STA.2
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DECD.2
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LDA.2
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DECA
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STA.2
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RET
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alike:
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SETD.0 SameText
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SWI osPrintString
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RSTA
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SWI osExit
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different:
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SETD.0 DifferentText
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SWI osPrintString
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INIA 0d1
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SWI osExit
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usage:
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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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firstFailed:
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SETD.0 FirstError
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SWI osPrintString
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INIA 0d2
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SWI osExit
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secondFailed:
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SETD.0 SecondError
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SWI osPrintString
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INIA 0d2
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SWI osExit
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firstReadFailed:
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SETD.0 FirstReadError
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SWI osPrintString
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INIA 0d2
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SWI osExit
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secondReadFailed:
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SETD.0 SecondReadError
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SWI osPrintString
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INIA 0d2
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SWI osExit
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#Data
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#Base 0x2000
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Arguments:
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#Reserve 0d256
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FirstBlocks:
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0x00 0x00
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SecondBlocks:
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0x00 0x00
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RemainingBlocks:
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0x00 0x00
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Index:
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0x00 0x00
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FirstCount:
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0x00 0x00
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SecondCount:
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0x00 0x00
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BytesLeft:
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0x00 0x00
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FirstBlock:
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#Reserve 0d256
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SecondBlock:
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#Reserve 0d256
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Usage:
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"compare: give me two files
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"
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FirstError:
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"compare: cannot find the first file
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"
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SecondError:
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"compare: cannot find the second file
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"
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FirstReadError:
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"compare: cannot read the first file
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"
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SecondReadError:
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"compare: cannot read the second file
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"
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SameText:
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"the same
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"
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DifferentText:
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"different
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"
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#Include text.asm
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