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
62 lines
1.6 KiB
NASM
62 lines
1.6 KiB
NASM
; A program for CosmOS to load and run.
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;
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; It carries no library of its own and no vector table. Everything it can do it asks the
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; system for, by name, through services.asm, which the system includes too. The order of
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; the names in that one file is what gives them their numbers, so neither side has a
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; number written down anywhere and the two cannot disagree about them.
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;
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; Compare it with Programs/loadable/hello.asm, which is the same idea one step earlier:
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; that one talks to the console port itself and stops with HALT, because when it was
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; written there was no system to ask and nowhere to give the machine back to.
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;
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; It is assembled for where it will live. #Base says so, and that makes the assembler
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; write it out as a loadable program rather than as a boot image. Nothing relocates
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; anything, so those addresses have to be the ones CosmOS puts it at.
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#Include services.asm
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#Program
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#Base 0x4000 ; Above the system, which keeps below here.
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greet:
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SETD.0 Opening
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SWI osPrintString
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SETD.0 Question
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SWI osPrintString
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SETD.0 Answer
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INIB 0d31
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SWI osReadLine
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SETD.0 Hello
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SWI osPrintString
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SETD.0 Answer
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SWI osPrintString
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SETD.0 Ending
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SWI osPrintString
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; Give the machine back. The system takes its Stack back at this point, so everything
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; this program pushed goes with it.
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SWI osExit
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#Data
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#Base 0x2000 ; And its data above the system's.
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Opening:
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"a program, loaded off a disk, running on the system that loaded it
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"
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Question:
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"what should I call you? "
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Hello:
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"hello, "
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Ending:
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". that is all I do.
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"
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; Thirty one characters and the zero byte that ends them.
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Answer:
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#Reserve 0d32
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