AnachronautandClaude Opus 5
588e02aff5
The memory map gave CosmOS 0x0000 through 0x1FFF of Program Memory and applications 0x2000 and above. CosmOS is 8141 bytes at the previous commit, which is fifty one bytes short of the line, and the next thing added to it went over. GOING OVER DOES NOT FAIL WHERE IT HAPPENS. Nothing enforces the division: an application says where it goes with #Base and the loader puts it there, so a CosmOS that has grown past 0x1FFF simply has the next program loaded written over the end of it. What breaks is whichever part of the shell that program happened to cover, at whatever later moment somebody uses it. It turned up here as the monitor's assemble command answering "I do not know" to valid instructions, several commands into a session, on a machine that had booted perfectly well. Both halves are doubled: applications now start at 0x4000 in Program Memory and 0x2000 in Data Memory. That is 16K of code and 8K of data for the system, against the 8775 and 2948 it uses today. Both were on the same trajectory, and moving them together means the twenty files that say #Base are edited once rather than twice. The standalone loader's loadable.asm keeps its old base: it belongs to the loader CosmOS grew out of, not to CosmOS, and its addresses answer to a different program. The unbased-segment diagnostic keeps its old base too - it exists to produce an error message that names the address, and the message is what is recorded. Tests/docs.sh now reads the two limits out of the table in the README and measures both segments against them. It reads them rather than being told them because the table is the specification, and this is the second time in this project that the thing nobody checked is the thing that rotted. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
178 lines
3.1 KiB
NASM
178 lines
3.1 KiB
NASM
; The assembler's front end on its own, one line per token.
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;
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; Prints the line each token started on, what the token turned out to be, how many bytes
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; it will come to, and the token itself between brackets so that whitespace at either end
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; would show if any ever leaked in.
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;
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; WHAT A TOKEN IS is the part worth checking here rather than at the far end. A wrong
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; classification does not produce a wrong byte in an obvious place - it produces a right
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; looking program of the wrong length, with everything after it shifted, and by then the
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; only symptom is that a label points at the middle of an instruction.
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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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SETD.0 Wanted
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INIB 0d23
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SWI osArgument
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SETD.0 Wanted
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LDA.0
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BRA nothingAsked
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SETD.0 Wanted
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CALL srcOpen
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BNQ noFile
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tokenLoop:
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CALL tokNext
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BNQ tokensDone
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SETD.0 TokLine
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LDA.0
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INCD.0
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LDB.0
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SWI osPrintNumber
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CALL clsToken
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BNQ badToken
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; Which of the six it turned out to be. The names are four characters and a space, so
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; the columns line up without any counting.
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SETD.0 TypeNames
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SETD.2 ClsType
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LDA.2
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CALL nameOfType
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SETD.1 NamePointer
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LDD.0.1
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SWI osPrintString
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SETD.0 ClsLength
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LDA.0
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INCD.0
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LDB.0
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SWI osPrintNumber ; Sixteen bits: a string of 255 characters is 256 bytes long.
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SETD.0 OpenMark
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SWI osPrintString
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SETD.0 TokText
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SWI osPrintString
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SETD.0 CloseMark
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SWI osPrintString
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BRI tokenLoop
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badToken:
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SETD.0 StoppedText
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SWI osPrintString
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SWI osExit
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; The name of type A, out of a table of fixed width entries so that no pointer arithmetic
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; is needed beyond a multiply by the width.
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nameOfType:
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SETD.0 TypeWidth
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LDB.0
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RSTA
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SETD.0 NameLeft
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STA.0
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SETD.2 ClsType
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LDA.2
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SETD.0 NameOffset
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CALL numZero
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nameLoop:
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SETD.2 ClsType
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LDA.2
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SETD.0 NameLeft
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LDB.0
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CCF
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SUB
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BRQ nameFound
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SETD.0 TypeWidth
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LDA.0
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SETD.0 NameOffset
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CALL numAddByte
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SETD.0 NameLeft
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LDA.0
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INCA
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STA.0
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BRI nameLoop
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nameFound:
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; The answer is left in NamePointer rather than in DP0, because a RET puts Data Pointers
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; 0 to 2 back as they were: a routine cannot hand back a pointer, only write one down.
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SETD.0 TypeNames
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SETD.1 NamePointer
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STD.0.1
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SETD.0 NamePointer
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SETD.2 NameOffset
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CALL numAdd
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RET
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tokensDone:
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SETD.0 DoneText
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SWI osPrintString
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SWI osExit
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nothingAsked:
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SETD.0 AskText
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SWI osPrintString
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SWI osExit
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noFile:
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SETD.0 NoFileText
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SWI osPrintString
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SWI osExit
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#Data
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#Base 0x2000
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Wanted:
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#Reserve 0d23
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OpenMark:
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" ["
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CloseMark:
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"]
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"
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; Six names of eleven characters each, counting the zero the assembler puts on the end of
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; every string. Written one to a line so that adding a type is adding a line.
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TypeNames:
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" keyword "
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" instr "
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" value "
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" string "
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" label: "
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" label "
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TypeWidth:
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0d11
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NameLeft:
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0x00
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NameOffset:
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0x00 0x00
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NamePointer:
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0x00 0x00
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StoppedText:
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"---- stopped: the assembler does not understand that
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"
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DoneText:
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"---- no more tokens
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"
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AskText:
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"say which file
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"
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NoFileText:
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"no such file
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"
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#Include scratch.asm
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#Include numbers.asm
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#Include source.asm
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#Include token.asm
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#Include classify.asm
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#Include table.asm
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