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.
Twenty four places moved Q into A or B by pushing it and popping it back.
That is four bus cycles and two bytes to do what MVQA does in one of each,
and several of them are inside loops - Life, the calculator, int8. Nineteen
more loaded zero with INIA 0d0 where RSTA says the same thing in one byte.
Both are equivalent at the CPU rather than by assertion: RSTA and INIA both
leave Status alone, and PSHQ followed by POPA nets to A = Q with the Stack
Pointer where it started. The one difference is that the pair leaves a copy
of Q in memory just below the Stack Pointer and MVQA does not, which
nothing here reads.
Five recorded outputs moved and every one of them says the change worked:
- 16x16Life fits five more generations into the same cycle budget, the
first 457 lines identical, because the loop got cheaper.
- Life.sbx is 1409 bytes rather than 1411, in three tests that list it.
- Edit.sbx is 1995 rather than 1996.
That last one broke a check I added this morning, and the hole is worth
recording: the CosmOS README's claim about Edit's size did not have the
word "Edit" on the same line as the number, because the subject was in the
sentence before, so the check that measures quoted sizes skipped it
silently. The sentence now names what it is talking about, which makes it
both checkable and clearer, and the check fails on a wrong number there.
Comments on either half of a replaced pair are carried onto the
instruction that replaces them, so nothing anybody wrote was lost.
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
Anachronaut
