AnachronautandClaude Opus 5
dbe58db660
Two applications that read a file too big for Data Memory: Type prints one, More pages it. Both sit on fileStream.asm, which wraps osFileInfo and osFileBlock into open-and-next so an application walks a file's blocks without repeating the service calls. The disk fixture is deliberately awkward: readable.txt crosses several blocks and carries no zero byte to be mistaken for an end marker, and empty.txt says that zero blocks is a valid file rather than an error. These three files were written by ChatGPT, as their headers record. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
142 lines
2.6 KiB
NASM
142 lines
2.6 KiB
NASM
; Read a named file from beginning to end, one block at a time.
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;
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; DP0 = filename
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; CALL fileStreamOpen Q = 0, or the osFileInfo error
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; CALL fileStreamNext Q = 0, or the osFileBlock error
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; DP3 = bytes in FileStreamBlock; zero means EOF
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;
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; This is application-side machinery built on CosmOS services, not a filesystem and not
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; yet an OS stream. Open remembers the address of the caller's filename, which must remain
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; valid until the one stream is finished.
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;
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; Written by ChatGPT for Anachronaut's SplitBit
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#Program
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fileStreamOpen:
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SETD.3 FileStreamName
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STD.0.3
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SWI osFileInfo
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BNQ fileStreamReturn
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PSHD.3
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POPB
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POPA
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SETD.3 FileStreamBlocks
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STA.3
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INCD.3
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STB.3
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SETD.3 FileStreamIndex
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RSTA
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STA.3
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INCD.3
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STA.3
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fileStreamReturn:
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RET
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fileStreamNext:
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SETD.3 FileStreamBlocks
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LDA.3
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INCD.3
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LDB.3
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OR
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BRQ fileStreamEnd
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SETD.3 FileStreamName
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LDD.0.3
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SETD.1 FileStreamBlock
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SETD.3 FileStreamIndex
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LDA.3
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INCD.3
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LDB.3
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SWI osFileBlock
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BNQ fileStreamReturn
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; DP3 is the service's return value and also the pointer this routine uses for all of
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; its bookkeeping. Keep the value before touching the pointer, then restore it at the
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; one successful return below.
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PSHD.3
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POPB
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POPA
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SETD.3 FileStreamCount
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STA.3
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INCD.3
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STB.3
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; Index++.
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SETD.3 FileStreamIndex
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INCD.3
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LDA.3
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INCA
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STA.3
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BNC fileStreamTakeBlock
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DECD.3
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LDA.3
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INCA
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STA.3
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fileStreamTakeBlock:
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; Blocks--.
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SETD.3 FileStreamBlocks
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INCD.3
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LDA.3
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BRA fileStreamBlocksBorrow
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DECA
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STA.3
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BRI fileStreamReadReturn
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fileStreamBlocksBorrow:
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INIA 0xFF
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STA.3
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DECD.3
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LDA.3
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DECA
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STA.3
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fileStreamReadReturn:
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SETD.3 FileStreamCount
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LDD.3.3
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RET
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fileStreamEnd:
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; There is no reset-pointer instruction. Two zero bytes through the Stack are the
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; literal construction of a zero Data Pointer.
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RSTA
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PSHA
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PSHA
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POPD.3
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RET
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; DP2 names a big-endian sixteen-bit byte count. Decrement it, returning Q = 0 when it
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; reached zero and nonzero while bytes remain. This is shared because correctly counting
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; a full 0x0100-byte block is the least interesting part of both applications to duplicate.
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fileStreamTakeRemaining:
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INCD.2
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LDA.2
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BRA fileStreamRemainingBorrow
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DECA
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STA.2
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DECD.2
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LDB.2
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INCD.2
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LDA.2
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OR
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RET
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fileStreamRemainingBorrow:
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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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LDB.2
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INCD.2
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LDA.2
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OR
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RET
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#Data
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FileStreamName:
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0x00 0x00
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FileStreamBlocks:
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0x00 0x00
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FileStreamIndex:
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0x00 0x00
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FileStreamCount:
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0x00 0x00
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FileStreamBlock:
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#Reserve 0d256
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