Start CosmOS with a script, and let a script hold its tongue

Three things scripts wanted, and they are one thing: a machine that can have a face. /System/Boot/startup.sh runs before anybody can type. Every way of reaching the prompt for the first time goes through it, including the one where there is no disk - in which case there is nothing to find and nothing is said. A MISSING one is ordinary and silent, because a clean install has none and a machine that complained every boot about a file nobody wrote would be teaching its owner to ignore it. One that is THERE and does not begin with #! is the other case entirely: somebody meant that to run. #quiet stops each line being echoed, #loud puts it back. The prompt and the echo go together, because together they are what makes a script look like typing, so a quiet script gets neither and what it prints is all that appears. A nested script inherits quiet - a build that asked for it meant its helpers too - and gets its own setting back when the helper returns. Anything else beginning with # is handed to the shell, which does not know it and stops the script, because a script that asked for something this shell cannot do should not carry on as though it had been given it. clear empties the screen, which the console has been able to do since before there was a screen to do it on. THE PROMPT IS NOW SAID BY WHOEVER SUPPLIES THE LINE. It used to be said at the top of the loop, which is a decision made before the line is read and an answer not known until after - and it was wrong at both ends. #quiet is itself a line, so its prompt went out before anything knew to stay silent; and the line after a quiet script's last one comes from the console, having already been denied one. Off by exactly one line in opposite directions. A first attempt at this remembered whether the prompt had been skipped, which worked and was a flag standing in for a structure. The monitor's assembler prints a prompt of its own, so it reads through shellReadRaw, which is the same source without one. One admission. Handing the console its prompt back when a quiet script ended was a real fix when I wrote it and stopped being one an hour later, because the restructure above means the console's own path prompts whatever the flag holds. The comment claimed it fixed something. Breaking it on purpose changed nothing, which is how that was found, and it is now a comment saying so instead of a line pretending to work. The startup fixture ends QUIET on purpose: nothing puts the flag back when the outermost script finishes, so a script ending #loud would have tested the easy half. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
2026-08-30 16:59:23 -04:00
parent c28826df77
commit 553882d28d
13 changed files with 297 additions and 40 deletions
@@ -95,7 +95,7 @@ boot:
  ; to give back: anything wrong past here can be fixed from the prompt, and nothing wrong
  ; before it can be fixed at all.
  CALL sbfsBootState
-  BNQ prompt
+  BNQ bootStartup
  SETD.0 SbfsStateWas
  LDA.0
  INIB 0d1
@@ -103,18 +103,18 @@ boot:
  BRQ bootArrived
  INIB 0d2
  XOR
-  BNQ prompt
+  BNQ bootStartup

  ; Started by the fallback, so the system somebody asked for is not the one running. Said
  ; once, here, because there is nowhere else it would be noticed.
  SETD.0 OnFallback
  CALL printString
-  BRI prompt
+  BRI bootStartup

 bootArrived:
  RSTA
  CALL sbfsSetBootState
-  BRI prompt
+  BRI bootStartup
 bootNoDisk:
  RSTA
  STA.0
@@ -122,6 +122,30 @@ bootNoDisk:
  CALL printString
  CALL newLine

+; ---- Something to run before anybody types ----
+;
+; Every way of arriving at the prompt for the first time comes through here, which is the
+; point: a startup script should run whether the disk was marked, unmarked, or is not there
+; at all - and in the last case scriptOpen simply finds nothing.
+;
+; A MISSING ONE IS NOT A FAULT and says nothing, because a clean install has none and a
+; machine that complained at every boot about a file nobody wrote would be teaching its owner
+; to ignore it. A file that is THERE and is not a script is the other case entirely: somebody
+; meant it to run.
+bootStartup:
+  SETD.0 StartupName
+  CALL scriptOpen
+  BRQ bootReady
+  MVQA
+  INIB 0x01
+  CCF
+  SUB
+  BRQ bootReady             ; There is none, which is ordinary.
+  SETD.0 StartupNotOne
+  CALL printString
+  CALL newLine
+bootReady:
+
 ; ---- The loop ----
 ;
 ; The shell has two modes and one prompt that says which. Ordinary mode runs programs;
@@ -154,31 +178,15 @@ prompt:
  CALL scriptAbandon

 promptWhere:
-  ; Where you are, but only when that is not obvious. At the root the prompt is the one it
-  ; has always been, so a machine nobody has moved about on looks exactly as it did - and
-  ; every recorded test that never says "cd" keeps its recorded prompt.
-  SETD.0 SbfsCwd
-  LDA.0
-  INCD.0
-  LDB.0
-  OR
-  BRQ promptMode
-  CALL shellPath
-  SETD.0 CwdAt
-  LDD.0.0
-  CALL printString
-
-promptMode:
-  SETD.0 Mode
-  LDA.0
-  BRA promptPlain
-  SETD.0 MonitorPrompt
-  BRI promptSay
-promptPlain:
-  SETD.0 PromptText
-promptSay:
-  CALL printString
-
+  ; ---- The prompt is said by whoever turns out to be supplying the line ----
+  ;
+  ; Not here, which is where it was and where it cannot be right. The decision has to be made
+  ; before the line is read and the answer is not known until after: a quiet script's #quiet
+  ; is itself a line, so the prompt for it went out before anybody knew to stay silent, and
+  ; the line AFTER a quiet script's last one comes from the console and had already been
+  ; denied its prompt. Both were off by exactly one line and in opposite directions.
+  ;
+  ; So shellReadLine says it. It is the one place that knows.
  SETD.0 CommandLine
  INIB 0d63
  CALL shellReadLine
@@ -251,6 +259,11 @@ promptSay:
  CALL textSame
  BRQ doRename

+  SETD.0 CommandLine
+  SETD.1 ClearName
+  CALL textSame
+  BRQ doClear
+
  SETD.0 CommandLine
  SETD.1 EchoName
  CALL textSame
@@ -313,6 +326,35 @@ promptSay:
  CALL textSame
  BRQ doAssemble

+; Where you are, and then the prompt itself. A routine rather than a run of code in the loop,
+; because the loop is no longer the only thing that needs it - see shellReadTyped.
+sayPrompt:
+  ; Where you are, but only when that is not obvious. At the root the prompt is the one it
+  ; has always been, so a machine nobody has moved about on looks exactly as it did - and
+  ; every recorded test that never says "cd" keeps its recorded prompt.
+  SETD.0 SbfsCwd
+  LDA.0
+  INCD.0
+  LDB.0
+  OR
+  BRQ sayPromptMode
+  CALL shellPath
+  SETD.0 CwdAt
+  LDD.0.0
+  CALL printString
+
+sayPromptMode:
+  SETD.0 Mode
+  LDA.0
+  BRA sayPromptPlain
+  SETD.0 MonitorPrompt
+  BRI sayPromptSay
+sayPromptPlain:
+  SETD.0 PromptText
+sayPromptSay:
+  CALL printString
+  RET
+
 ; ---- Where a line comes from ----
 ;
 ; The whole of what a script is. Everything below this - splitting the line, matching it
@@ -329,13 +371,41 @@ shellReadLine:
  BNQ shellReadLine         ; That one ended. Ask again: something under it may still be
                            ; running, and only depth reaching nought means the console.

-  ; Echoed, so that a script working can be watched and a script failing says where. It is
-  ; printed after the prompt, so it reads exactly like somebody typing it.
+  ; The prompt and the echo are one thing - together they look like somebody typing - so a
+  ; quiet script gets neither, and everything else gets both in that order.
+  SETD.1 ScriptQuiet
+  LDA.1
+  BNA shellReadQuiet
+  CALL sayPrompt
  CALL printString
  CALL newLine
+shellReadQuiet:
  RET

 shellReadTyped:
+  CALL sayPrompt
+  CALL readLine
+  RET
+
+; ---- The same, for a caller that prints a prompt of its own ----
+;
+; The monitor's assembler shows the address it is about to write to and then asks for a line,
+; so it must not also get the shell's. It still wants the line to come from the script when
+; there is one, which is what lets a script carry a block of assembly.
+shellReadRaw:
+  SETD.1 ScriptDepth
+  LDA.1
+  BRA shellReadRawTyped
+  CALL scriptLine
+  BNQ shellReadRaw
+  SETD.1 ScriptQuiet
+  LDA.1
+  BNA shellReadRawQuiet
+  CALL printString
+  CALL newLine
+shellReadRawQuiet:
+  RET
+shellReadRawTyped:
  CALL readLine
  RET

@@ -1588,6 +1658,16 @@ fileComplain:
  CALL newLine
  BRI commandFailed

+; ---- clear ----
+;
+; The console has done this since before there was a screen to do it on: writing 1 to the
+; command port. On a terminal it is what a terminal does with it, and on the Voyager it is
+; the screen going blank and the cursor going home.
+doClear:
+  INIA 0x01
+  OUTA 0x05
+  BRI prompt
+
 ; ---- echo ----
 ;
 ; Says the rest of the line and nothing else. Say.sbx has done this since before there were
@@ -3206,7 +3286,7 @@ assembleLine:

  SETD.0 AsmLine
  INIB 0d40
-  CALL shellReadLine
+  CALL shellReadRaw

  INA 0x01
  INIB 0x02                 ; ENDED, so there is nothing more to assemble.
@@ -3624,6 +3704,7 @@ PromptText:
 LineFailed:
  0x00

+
 LastStatus:
  0x00

@@ -3640,6 +3721,10 @@ ScriptNotOne:
 "do: that is not a script - it wants #! on the first line"
 ScriptTooDeep:
 "do: scripts are only four deep"
+StartupName:
+"/System/Boot/startup.sh"
+StartupNotOne:
+"startup.sh is there but does not begin with #!, so it was not run"
 ScriptStopped:
 "stopped: that line did not work"
 Unknown:
@@ -3700,7 +3785,8 @@ mkdir <path>         make a directory
 rmdir <path>         remove an empty one"
 HelpScriptText:
 "do <file>    run the lines in a file, which must start with #!
-echo [words] say them"
+echo [words] say them
+clear        empty the screen"
 HelpMoreText:
 "delete <file>        take it off the disk
 rename <file> <to>   call it something else
@@ -3828,6 +3914,8 @@ DoName:
 "do"
 EchoName:
 "echo"
+ClearName:
+"clear"
 LoadName:
 "load"
 RunName: