DPUP takes an immediate, so an offset of one is legal and does exactly the
right thing. It is also three bytes where INCD is two, and reads as "offset
the pointer up by one" where INCD reads as "step the pointer".
56 of them across 15 files: the system, the assembler, the editor, and eight
test programs. CosmOS is 9,564 bytes to 9,537, the native assembler 11,648
to 11,635, and every program in the repository together 49 bytes lighter.
The worst offender was numbers.asm, written this week, where every sixteen
bit helper reaches the low byte and comes back the long way round. It is the
file every other part of the assembler includes, so it is the first thing
anybody reads when they go looking - and it was teaching them the long way.
Pattern matched off sbfs.asm rather than off the instruction table I had
just embedded in two programs.
THIS IS NOT TWO WAYS TO DO ONE THING. DPUP takes an arbitrary number, so one
is inevitably among them; INCD earns its place by making the common case a
byte cheaper. The overlap is structural and the choice is a usage question,
which is a linter's job rather than an ISA's - "DPUP.n 0d01: INCD.n does
this in a byte less" is a mechanical rule with no judgement in it.
Nothing needed re-recording, which was not a foregone conclusion: cosmosBreak
prints the system addresses the registers happened to hold, and they did not
move. Both assemblers still produce identical bytes and CosmOS still builds
itself to a fixed point.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
The editor included sbfs.asm and console.asm, which was 3235 of its 4941
bytes. Both come out: reading and writing a file, printing and reading a
line are services now, and sbfsMount goes entirely because the system has
already mounted the disk. Only text.asm remains, at 357 bytes, because
textSame and textNumber own nothing and touch no device - sharing those is
a linker's job rather than an operating system's.
4941 bytes to 1983, a little better than predicted because dropping the
mount and the blocks-and-tail arithmetic went with the library rather than
being translated.
ConsoleEndOfInput went with console.asm, so the end of input is now read
from the console status port. That is better than what it replaced: the
port is there whether or not the system is.
Nothing it does changed, and that is checked rather than asserted. The
recorded output of the cosmosEdit test does not move by a single byte
across this commit - a test written days before the rewrite, checking a
property rather than an output, and therefore able to verify a change it
knew nothing about.
One thing is lost and worth naming: there is no way to ask whether a disk
is present, so the editor's "there is no disk" message is gone. On a
diskless machine it now opens an empty document and fails at w instead. The
shell already refuses to load without a disk, so the editor cannot normally
be reached that way.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
AnachronautandClaude Opus 5