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NAUG Appendix A + B — OSBYTE / OSWORD index

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NAUG Appendix A + B — OSBYTE / OSWORD Index

Holmes & Dickens, The New Advanced User Guide, pp.443-448. These appendices are directory tables — they list every OSBYTE (&00-&FF) and OSWORD (&00-&FF) with a one-line function description and a page reference to where the full semantics live in the body of the book.

For each call, the detailed protocol (entry params, exit state, side effects, machine-specific behaviour) is in the chapter listed in the page column. The wiki files osbyte and osword hold the directory; full semantics for individual calls are filled in as the referenced chapter is ingested.

OSBYTE — JSR &FFF4 (indirected through &20A)

Standard call:

LDA #call_number    ; OSBYTE number in A
LDX #x_value
LDY #y_value
JSR &FFF4

Two common patterns:

  • Read/write state byte: NEW = (OLD AND Y) EOR X. To read: X=0, Y=&FF → OLD returned in X. To write: X=value, Y=0 → OLD returned in X, byte set to value.
  • Do-an-action: X and Y are entry parameters; exit state varies.

OSWORD — JSR &FFF1 (indirected through &20C)

Standard call:

LDA #call_number
LDX #param_block AND 255
LDY #param_block DIV 256
JSR &FFF1

OSWORD always uses a parameter block in memory at the address in X+Y. The block layout depends on the call.

Filed into

  • osbyte — Full directory of OSBYTE calls. Each row links to the wiki chapter source page (e.g. naug-ch13-video) when ingested; otherwise lists the NAUG page number.
  • osword — Full directory of OSWORD calls, same format.

Open follow-ups

The chapter-page references in this index mean that every chapter of NAUG is potentially the canonical source for some OSBYTE/OSWORD. Backfill semantics as chapters are ingested. Notable chapters with concentrations of OSBYTE/OSWORD detail:

  • Ch6 OS Introduction — generic OS calls (next ingest)
  • Ch13 Video — &13, &86, &87, &9A, &9B, &A0, &A5, &AE, &AF, &B8, &B9, &C1-&C3, &D9, &DA, plus OSWORDs &09, &0A, &0B, &0C, &0D (ingested ✓)
  • Ch12 Memory — &44, &45, &6C, &70-&72, &84, &85, &FA, &FB, &EF, &FE (ingested ✓)
  • Ch8 Interrupts — &BA, &CB, &E7, &E8, &E9 (ingested ✓)
  • Ch7 Events — &0D, &0E
  • Ch9 Buffers — &15, &80 (also ADC), &88-&8A, &98, &99, &91
  • Ch14 Keyboard — &0B, &0C, &76-&7A, &C4-&CA, &DB-&E4
  • Ch15 Serial — &07, &08, &02, &03, &9C, &B0, &B1, &B5, &BF, &C0, &CB-&CD, &F2
  • Ch16 Filing — &77, &7F, &87-&8D, &C6, &C7, &6D
  • Ch17 Paged ROMs — &8D-&8F, &A4, &A8-&AB, &BA-&BB, &FC (next-next ingest)
  • Ch18 Tube — &9D, &82, &EA
  • Ch19 Clocks/CMOS — &A1, &A2, &F3, OSWORDs &01-&04, &0E, &0F
  • Ch20 ADC — &10, &11, &80, &BC-&BE
  • Ch21 Sound — &D1-&D6, &74, &E8, OSWORDs &07, &08
  • Ch24 Misc — &00, &01, &05, &06, &88, &7B, &F1, &F0, &F5-&F9, &FD, &FF

This wiki is curated by Claude following the LLM-Wiki methodology — a human curates source documents, the LLM compiles structured cross-linked markdown. Content may contain errors, omissions, or stale claims. For authoritative information refer to the original source documents in the bbc-documents GitHub archive.

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