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MON — SINTRAN III Monitor Calls (hub)

The one place that ties together all monitor-call documentation: the ND-100 call system, the ND-500 cross-processor call system, how they map to each other, and how to find the implementation code for any MON call.

This folder is the index/hub. Some authoritative documents remain in their established locations (to preserve cross-repo links) and are linked from here.

Start here

Document What it gives you
ND500-MON-ACTIVATION-AND-MAPPING.md The end-to-end process: how an ND-500 MON call is activated, routed 500↔100, dispatched, handled, and answered — with Mermaid flow and source refs. Read this first.
ND500-MON-CALL-ROUTING-MAP.md (pending — being generated) The per-call routing table: for every MON number, which actor handles it (ND-500 system monitor / ND-100 driver / ND-500-local) and whether it forwards

The two MON-call systems

A. ND-100 monitor calls (MON 0..377, issued by ND-100 programs)

Dispatched by the CPU on program level 14 through the 256-entry GOTAB jump table. - ../../OS/23-MON-CALL-DISPATCH-DEVELOPER-GUIDE.md — how dispatch works, reading GOTAB in memory, DAP breakpoints, disassembly (level 14 → GOTAB(n) → handler). - Call definitions (name, parameters, examples): ../../../Developer/MON/ — Monitor Calls.md and the per-call YAMLs in Developer/MON/calls/. - Undocumented / unclear ND-100 calls to reverse-engineer: ../../../tools/sintran-segment-carver/ghidra-tasks/TASK-05-undocumented-mon-calls.md.

B. ND-500 monitor calls (issued by ND-500 programs)

Handled first by the ND-500 System Monitor (segment S3SM5, ND-500 code), which handles some locally and forwards others to the ND-100 (level 12). - ND500-MON-ACTIVATION-AND-MAPPING.md — the full activation/mapping/response process (this folder). - ../ND500-MONITOR-CALL-MECHANISM.md — inter-processor call mechanism, message buffer layout. - ../ND500-MONITOR-CALL-PARAMETER-PASSING.md — message/parameter offsets, NUMPA write-back mask, the 500–523 dispatch table. - ../ND500-MON-RE-FINDINGS.md — ND-500-MON-J:PROG background monitor, MON 60B (N500M) subfunction array. - ../swapper/swapper-k01-deep-analysis.md — proof the swapper is NOT the MON dispatcher (it forwards swap work via MON 377B). - ND-500 System Monitor disassembly + how to align symbols: ../../../tools/sintran-segment-carver/versions/L-VSX-500/segments/030-S3SM5-DISASSEMBLY-PROMPT.md and the disassembly 030-S3SM5.asm in that folder.

The bridge (ND-100 ↔ ND-500 transport)

Kernel NPL source (annotated)

How to find the code for any MON call (quick guide)

  1. Which system? ND-100 program → system A (level 14 / GOTAB). ND-500 program → system B (ND-500 System Monitor first).
  2. ND-100 call: handler = GOTAB(n); follow the method in the dispatch guide.
  3. ND-500 call: look it up in the routing map; then either read the named ND-100 handler in MP-P2-N500.NPL (calls 500–523), or SEGMONC on the ND-100 (calls < 500 standard), or disassemble 030-S3SM5.bin with nd500-dis (calls handled ND-500-side). Details: activation doc §5.

Status of the reverse-engineering effort

  • ND-500 MON calls (410–427, 500–523): routing established; ND-100-side handlers (500–523) are named and readable in MP-P2-N500.NPL; the ND-500-side handlers are in 030-S3SM5.asm (RE in progress).
  • ND-100 MON calls (0–377): dispatch mechanism fully documented (doc 23); per-handler RE tracked in TASK-05 (handlers live in the paged level-4 view — via live DAP recovery or composite-view reconstruction).