CosmOS pre-alpha and launchable application versions of old programs.

2026-08-17 15:31:49 -04:00
parent eff6902bcf
commit 91c9d49d1b
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+; Walking the directory of a SplitBit filesystem.
+;
+; sbfsFind answers a question about one name. This is the other thing a directory is for:
+; being listed. The disk was made by SplitDisk, so the order and contents here are what
+; the other implementation of the format wrote, not what this one assumed.
+;
+; The cases that matter are all on this disk already. There are twelve files, which is
+; more than the eight an entry block holds, so the walk has to cross from the first
+; directory block into the second. aName22CharactersLong! fills the name field exactly and
+; so has no zero byte to end it, which is what the twenty third byte of SbfsName is for.
+; empty.txt has no blocks at all.
+;
+; The count at the end is the proof that the walk stopped where the directory did. A walk
+; that stepped its pointer only when it took an entry would loop forever on a free one,
+; and one that stepped only when it skipped would hand out every eighth file.
+;
+; Correct output is the twelve files with their sizes, then how many there were.
+
+#Include console.asm
+#Include sbfs.asm
+
+#Program
+
+start:
+  CALL sbfsMount
+  BRQ mounted
+  SETD.0 NoMount
+  CALL printString
+  CALL newLine
+  HALT
+
+mounted:
+  ; Nothing found yet.
+  RSTA
+  SETD.0 Seen
+  STA.0
+
+  CALL sbfsFirst
+  BRI walkCheck
+
+walkStep:
+  CALL sbfsNext
+walkCheck:
+  BNQ walkDone
+
+  SETD.0 Seen
+  LDA.0
+  INCA
+  STA.0
+
+  SETD.0 SbfsName
+  CALL printString
+
+  ; Line the sizes up, so a name that fills the field and a short one both read cleanly.
+  SETD.0 SbfsName
+  CALL nameWidth
+  MVQA
+  CALL printSpaces
+
+  ; A file is its blocks times 256 plus its tail, which is the block count in the high
+  ; byte and the tail in the low one. Nothing has to multiply anything.
+  SETD.0 SbfsFileBlocks
+  DPUP.0 0d01
+  LDA.0
+  SETD.1 Size
+  STA.1
+  SETD.0 SbfsFileTail
+  LDA.0
+  SETD.1 Size
+  INCD.1
+  STA.1
+
+  SETD.0 Size
+  CALL printWordDecimal
+  CALL newLine
+  BRI walkStep
+
+walkDone:
+  SETD.0 Total
+  CALL printString
+  SETD.0 Seen
+  LDA.0
+  CALL printByteDecimal
+  CALL newLine
+  HALT
+
+; DP0 names a string. Q is how many spaces would pad it out to twenty four characters.
+; A name that is already that long gets one space, because none at all would run the
+; name into the number.
+nameWidth:
+  INIA 0d24
+  SETD.1 Padding
+  STA.1
+widthLoop:
+  LDA.0
+  BRA widthDone
+  SETD.1 Padding
+  LDA.1
+  DECA
+  STA.1
+  BRA widthFloor        ; It is already too long to pad.
+  INCD.0
+  BRI widthLoop
+widthFloor:
+  INIA 0d1
+  SETD.1 Padding
+  STA.1
+widthDone:
+  SETD.1 Padding
+  LDA.1
+  RSTB
+  CCF
+  ADD
+  RET
+
+#Data
+
+NoMount:
+"no filesystem on that disk"
+Total:
+"files: "
+
+Seen:
+  0x00
+Padding:
+  0x00
+Size:
+  0x00 0x00
+
+#Vectors
+
+  Boot  start