Files
SplitBit-Emulator/Programs/CosmOS/Apps/More.asm
T
AnachronautandClaude Opus 5 588e02aff5 Double CosmOS's half of the machine, and check that it fits
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
2026-08-24 22:21:02 -04:00

152 lines
2.4 KiB
NASM

; Read a text file one screen at a time.
;
; Twenty two lines are shown before a prompt. Space advances another screen, Return one
; line, and q gives the machine back to CosmOS. This is forward-only on purpose: the file
; stream holds one block and never asks the whole document to fit in memory.
;
; Written by ChatGPT for Anachronaut's SplitBit
#Include services.asm
#Program
#Base 0x4000
start:
SETD.0 Name
INIB 0d29
SWI osArgument
SETD.0 Name
LDA.0
BRA noName
CALL fileStreamOpen
BNQ openFailed
CALL fullPage
nextBlock:
CALL fileStreamNext
BNQ readFailed
PSHD.3
POPB
POPA
SETD.2 Remaining
STA.2
INCD.2
STB.2
OR
BRQ finished
SETD.1 FileStreamBlock
SETD.2 Remaining
printLoop:
LDA.1
OUTA 0x00
INIB 0x0A
XOR
BNQ bytePrinted
SETD.3 LinesLeft
LDA.3
DECA
STA.3
BNA bytePrinted
CALL pause
BNQ finished
bytePrinted:
INCD.1
CALL fileStreamTakeRemaining
BRQ nextBlock
BRI printLoop
; Ask for one key without asking for Return. The console is put back immediately,
; including on q and end of redirected input.
pause:
SETD.0 MorePrompt
SWI osPrintString
INIA 0x01
OUTA 0x02
INA 0x00
PSHA ; Keep the key while A is used to restore line mode.
RSTA
OUTA 0x02
POPA
SETD.0 ClearPrompt
SWI osPrintString
INIB 0x71 ; q
XOR
BRQ pauseQuit
INIB 0xFF ; end of redirected input
XOR
BRQ pauseQuit
INIB 0x0A ; Return: one more line.
XOR
BRQ oneLine
INIB 0x20 ; Space: one more screen.
XOR
BNQ pause ; Ignore every other key.
CALL fullPage
RSTA
RSTB
OR
RET
oneLine:
SETD.3 LinesLeft
INIA 0x01
STA.3
RSTA
RSTB
OR
RET
pauseQuit:
RSTA
INIB 0x01
OR
RET
fullPage:
SETD.3 LinesLeft
INIA 0d22
STA.3
RET
noName:
SETD.0 Usage
SWI osPrintString
SWI osExit
openFailed:
SETD.0 OpenError
SWI osPrintString
BRI printError
readFailed:
SETD.0 ReadError
SWI osPrintString
printError:
RSTA
MVQB
SWI osPrintNumber
SETD.0 NewLine
SWI osPrintString
finished:
SWI osExit
#Data
#Base 0x2000
Usage:
"more: give me a file name
"
OpenError:
"more: cannot find the file, error "
ReadError:
"more: cannot read the file, error "
NewLine:
0x0A 0x00
MorePrompt:
"-- more --"
ClearPrompt:
0x0A 0x00
Name:
#Reserve 0d29
Remaining:
0x00 0x00
LinesLeft:
0x00
#Include fileStream.asm