Edit: use the system's services instead of carrying the filesystem

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>

Programs/CosmOS/Apps/Edit.asm

@@ -75,33 +75,39 @@ start:
   RSTA
   STA.0
 
-  CALL sbfsMount
-  BNQ noDisk
-
   CALL loadFile
 
   SETD.0 FileName
-  CALL printString
+  SWI osPrintString
   SETD.0 CommaText
-  CALL printString
+  SWI osPrintString
   CALL countLines
   MVQA
-  CALL printByteDecimal
+  CALL printByte
+  ; One line is not one lines. The same care the shell's file listing takes, for the same
+  ; reason: it costs four instructions and reads as carelessness without them.
+  DECA
+  BRA oneLine
   SETD.0 LinesText
-  CALL printString
+  BRI sayLines
+oneLine:
+  SETD.0 LineText
+sayLines:
+  SWI osPrintString
   CALL newLine
 
 commandLoop:
   SETD.0 PromptText
-  CALL printString
+  SWI osPrintString
   SETD.0 Command
   INIB 0d40
-  CALL readLine
+  SWI osReadLine
 
   ; Running out of typing ends it, the same way it ends the shell.
-  SETD.0 ConsoleEndOfInput
-  LDA.0
-  BNA quit
+  INA 0x01
+  INIB 0x02                 ; ENDED
+  AND
+  BNQ quit
 
   SETD.0 Command
   LDA.0
@@ -150,7 +156,7 @@ commandArgument:
   BRQ quit
 
   SETD.0 WhatText
-  CALL printString
+  SWI osPrintString
   CALL newLine
   BRI commandLoop
 
@@ -159,15 +165,10 @@ quit:
 
 noName:
   SETD.0 NoNameText
-  CALL printString
+  SWI osPrintString
   CALL newLine
   SWI osExit
 
-noDisk:
-  SETD.0 NoDiskText
-  CALL printString
-  CALL newLine
-  SWI osExit
 
 ; ---- The commands ----
 
@@ -189,13 +190,14 @@ doInsert:
   BRA insertNeedsLine
 insertLoop:
   SETD.0 EnteringText
-  CALL printString
+  SWI osPrintString
   SETD.0 Entry
   INIB 0d80
-  CALL readLine
-  SETD.0 ConsoleEndOfInput
-  LDA.0
-  BNA commandLoop
+  SWI osReadLine
+  INA 0x01
+  INIB 0x02                 ; ENDED
+  AND
+  BNQ commandLoop
 
   ; A line that is just a dot ends it, which is the oldest convention there is for this.
   SETD.0 Entry
@@ -216,7 +218,7 @@ insertLoop:
 
 insertNeedsLine:
   SETD.0 NeedsLineText
-  CALL printString
+  SWI osPrintString
   CALL newLine
   BRI commandLoop
 
@@ -228,13 +230,14 @@ doChange:
   BNQ noSuchLine
 
   SETD.0 EnteringText
-  CALL printString
+  SWI osPrintString
   SETD.0 Entry
   INIB 0d80
-  CALL readLine
-  SETD.0 ConsoleEndOfInput
-  LDA.0
-  BNA commandLoop
+  SWI osReadLine
+  INA 0x01
+  INIB 0x02                 ; ENDED
+  AND
+  BNQ commandLoop
 
   SETD.0 Entry
   CALL makeNode
@@ -257,7 +260,7 @@ doDelete:
 
 noSuchLine:
   SETD.0 NoLineText
-  CALL printString
+  SWI osPrintString
   CALL newLine
   BRI commandLoop
 
@@ -265,17 +268,17 @@ doWrite:
   CALL writeFile
   BNQ writeFailed
   SETD.0 WrittenText
-  CALL printString
+  SWI osPrintString
   SETD.0 WroteSize
-  CALL printWordDecimal
+  CALL printWord
   SETD.0 BytesText
-  CALL printString
+  SWI osPrintString
   CALL newLine
   BRI commandLoop
 
 writeFailed:
   SETD.0 NoWriteText
-  CALL printString
+  SWI osPrintString
   CALL newLine
   BRI commandLoop
 
@@ -513,9 +516,9 @@ listStep:
 
   SETD.0 Counted
   LDA.0
-  CALL printByteDecimal
+  CALL printByte
   SETD.0 ColonText
-  CALL printString
+  SWI osPrintString
 
   PSHD.3
   POPD.1
@@ -558,23 +561,19 @@ listDone:
 ; document rather than a mistake, which is what makes this the way to start one.
 loadFile:
   SETD.0 FileName
-  CALL sbfsFind
-  BNQ loadNothing
-
   SETD.1 0x40 0x00
-  CALL sbfsRead
+  SWI osFileRead
   BNQ loadNothing
 
-  ; How many bytes came back: the block count is the high byte of the length and the tail
-  ; is the low one, which is how a size is put together everywhere on this disk.
-  SETD.0 SbfsFileBlocks
-  DPUP.0 0d01
-  LDA.0
-  SETD.1 ReadLeft
-  STA.1
-  SETD.0 SbfsFileTail
-  LDA.0
+  ; How many bytes came back. The service says so in DP3, which is one of the two things a
+  ; service is allowed to answer in, and a file that fits in memory has a length that fits
+  ; in a pointer. A name that is not on the disk fails here, and that is a new document
+  ; rather than a mistake.
+  PSHD.3
+  POPA                      ; The low byte is on top, the way a pointer is pushed.
+  POPB
   SETD.1 ReadLeft
+  STB.1
   INCD.1
   STA.1
 
@@ -715,24 +714,9 @@ writeOut:
   ; whole blocks and the low byte is the tail.
   SETD.2 WroteSize
   STD.1.2
-  SETD.0 WroteSize
-  LDA.0
-  INIB 0x40
-  CCF
-  SUB
-  MVQA
-  SETD.0 SbfsFileBlocks
-  RSTB
-  STB.0
-  INCD.0
-  STA.0
-  SETD.0 WroteSize
-  INCD.0
-  LDA.0
-  SETD.0 SbfsFileTail
-  STA.0
 
-  ; The size the file is about to be, said in bytes, before saving changes what these mean.
+  ; Turn where it stopped into how big it is, which is one subtraction: the high byte less
+  ; 0x40 and the low byte as it stands.
   SETD.0 WroteSize
   LDA.0
   INIB 0x40
@@ -740,11 +724,44 @@ writeOut:
   SUB
   MVQA
   SETD.0 WroteSize
-  STA.0
+  STA.0                     ; WroteSize is now a count of bytes, which is what gets printed.
+
+  ; And into the two registers the service takes a size in.
+  SETD.0 WroteSize
+  LDA.0
+  INCD.0
+  LDB.0
 
   SETD.0 FileName
   SETD.1 0x40 0x00
-  CALL sbfsSaveFile
+  SWI osFileSave
+  RET
+
+; ---- All that is left of a console library ----
+;
+; Printing a string and reading a line are services now. These three are only here because
+; what a service takes is not quite what the call sites have: a number arrives in two
+; registers rather than one or in memory, and a line feed is a string like any other.
+
+newLine:
+  SETD.0 Break
+  SWI osPrintString
+  RET
+
+; A is a byte.
+printByte:
+  PSHA
+  POPB
+  RSTA
+  SWI osPrintNumber
+  RET
+
+; DP0 is a two byte number, most significant first.
+printWord:
+  LDA.0
+  INCD.0
+  LDB.0
+  SWI osPrintNumber
   RET
 
 ; DP0 is a two byte number, A is a byte. Adds the one to the other.
@@ -765,6 +782,8 @@ addByteToWord:
 
   #Base 0x1000
 
+Break:
+  0x0A 0x00
 PromptText:
 "> "
 EnteringText:
@@ -775,6 +794,8 @@ CommaText:
 ", "
 LinesText:
 " lines"
+LineText:
+" line"
 WrittenText:
 "written, "
 BytesText:
@@ -785,8 +806,6 @@ WhatText:
 "l list, a add, i insert, c change, d delete, w write, q quit"
 NoNameText:
 "edit what? try: run edit <file>"
-NoDiskText:
-"there is no disk"
 NoLineText:
 "there is no such line"
 NeedsLineText:
@@ -824,6 +843,4 @@ ReadLeft:
 WroteSize:
   0x00 0x00
 
-#Include sbfs.asm
 #Include text.asm
-#Include console.asm