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.
142 lines
1.9 KiB
NASM
142 lines
1.9 KiB
NASM
; A Fibonacci number generating program that uses four bytes to store the value.
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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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; Swap ValueB and ValueA.
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; First, store ValueA on the stack.
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SETD ValueA
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LDA
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PSHA
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INCD
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LDA
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PSHA
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INCD
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LDA
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PSHA
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INCD
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LDA
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PSHA
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; Next, store ValueB on the stack.
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SETD ValueB
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LDA
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PSHA
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INCD
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LDA
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PSHA
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INCD
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LDA
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PSHA
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INCD
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LDA
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PSHA
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; Then pop ValueB into ValueA.
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SETD ValueA
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INCD INCD INCD
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POPA
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STA
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DECD
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POPA
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STA
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DECD
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POPA
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STA
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DECD
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POPA
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STA
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; Then pop ValueA into ValueB.
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SETD ValueB
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INCD INCD INCD
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POPA
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STA
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DECD
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POPA
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STA
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DECD
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POPA
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STA
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DECD
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POPA
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STA
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; Print ValueA.
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SETD ValueA
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INCD INCD INCD
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LDA
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CALL printByteHex
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DECD
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LDA
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CALL printByteHex
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DECD
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LDA
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CALL printByteHex
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DECD
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LDA
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CALL printByteHex
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CALL blankSpace
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; Now add ValueA and ValueB, and store the result in ValueA.
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; Add the lowest bytes of ValueA and ValueB.
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SETD ValueB
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LDB
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SETD ValueA
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LDA
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ADD
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; Store it in ValueA's lowest byte.
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STQ
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; Add the second lowest bytes of ValueA and ValueB.
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SETD ValueB
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INCD
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LDB
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SETD ValueA
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INCD
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LDA
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ADD
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; Store it in ValueA's second lowest byte.
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STQ
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; Add the second highest bytes of ValueA and ValueB.
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SETD ValueB
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INCD INCD
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LDB
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SETD ValueA
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INCD INCD
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LDA
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ADD
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; Store it in ValueA's third lowest byte.
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STQ
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; Add the highest bytes of ValueA and ValueB.
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SETD ValueB
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INCD INCD INCD
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LDB
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SETD ValueA
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INCD INCD INCD
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LDA
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ADD
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; If this addition overflows, we're done.
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BRC end
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; Otherwise, store the result in ValueA's highest byte.
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STQ
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; And branch back to the beginning of the loop.
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BRI start
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end:
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CALL lineFeed
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;HALT
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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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ValueA:
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; Lowest byte ... Highest byte.
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0x01 0x00 0x00 0x00
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ValueB:
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; Lowest byte ... Highest byte.
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0x00 0x00 0x00 0x00
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#Include print.asm
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