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ND-500/5000 Monitor J04 (MON-DEBUG:PROG) - Reverse-Engineering

Analysis of nd-500-mon-j04.prog, the ND-100 program "ND-500/5000 MONITOR Version J04 88. 6.16 / 88. 8.17" (embedded name MON-DEBUG:PROG). It runs on the ND-100 and is the operator's front end to the ND-500 (@nd-500 -> N500: prompt) - the program that loads code into the ND-500 and drives it across the bus interface.

All repo paths below are relative to the repo root E:\Dev\Ronny\NDInsight. The ORIGINAL source package (disk image + the .prog original) remains outside the repo at /mnt/d/ND/500/ND-500(0) System Package for SINTRAN IIIVSX L/.

Start here

SINTRAN/ND500/nd-500-mon/nd-500-mon-j04.prog.md - the full analysis: container/memory layout, entry point, the single MON 60 gateway, the subfunction map, and the end-to-end bus path.

The one big finding

The monitor never touches the ND-500 bus hardware itself (zero IOX/IOXT). It drives the ND-500 through exactly one MON 60 (N500M) instruction at address 146256B, fed by a fan-in of 159 call sites -> 123 thunks -> 1 gateway -> 1 MON 60. Below the MON 60, the 3022 IOX registers, the mailbox, the TAG handshake, and the level-12 interrupt all live in the privileged SINTRAN driver. On the ND-100 side the front door is MON 60/N500M -> FPT2ENTRY ("ENTER ND-500 SYSTEM MONITOR") -> the 5MPM shared-memory message -> the ND-500.

Files

File (repo-relative) What it is
SINTRAN/ND500/nd-500-mon/nd-500-mon-j04.prog Original SINTRAN III two-bank :PROG binary
SINTRAN/ND500/nd-500-mon/nd-500-mon-j04.prog.asm ND-100 disassembly (byte-swapped to big-endian, base 0, ~65460 lines)
SINTRAN/ND500/nd-500-mon/nd-500-mon-j04.prog.md Full analysis (start here): MON 60 gateway, subfunction map, diagrams
SINTRAN/ND500/nd-500-mon/nd-500-mon-j04-bank1.bin Big-endian program bank image - load into a big-endian ND-100 Ghidra at address 0 (entry at address 9)
SINTRAN/ND500/nd-500-mon/nd-500-mon-j04-bank2.bin Big-endian data bank image (alternate page table)
SINTRAN/ND500/nd-500-mon/nd-500-mon-j04-symtab1.sym Recovered symbol-table RESIDUE #1 (block-0 tail)
SINTRAN/ND500/nd-500-mon/nd-500-mon-j04-symtab2.sym Recovered symbol-table RESIDUE #2 (inter-bank padding)
SINTRAN/ND500/nd-500-mon/nd-500-control-store-debug-handoff.md RetroCore emulator control-store / TAG-OUT DMA "Unmapped memory" crash analysis
SINTRAN/ND500/nd-500-mon/ND500-BRINGUP-BUS-INTERFACE-FEEDBACK.md Bootstrap + bus-interface synthesis for the CPU-connect goal
SINTRAN/ND500/nd-500-mon/COMMAND-DISPATCH-TABLE-CARVED-2026-08-02.md The outer command dispatch table [V] - how an operator command name reaches its handler, plus the complete 151-command name -> handler map. Closes open question 9
SINTRAN/ND500/nd-500-mon/RECOVER-DOMAIN-WORKER-AND-SEGMENT-LOAD-CARVED-2026-08-02.md The PLACE call graph [V] - RECOVER-DOMAIN -> handler -> worker -> START-PLACE / ISEGLOAD x2 / END-PLACE, all 159 MON 60 thunk call sites mapped, and the proof that the segment-load defect is NOT monitor-side
SINTRAN/ND500/nd-500-mon/mon60-callers/ The MON 60 carve (see below)

Note: a :PROG file carries no symbol table; the two .sym files are a leaked fragment of the MON-DEBUG build's own symbol table found in padding, kept because it names the ND-500 command routines.

mon60-callers/ - the MON 60 carve

  • SINTRAN/ND500/nd-500-mon/mon60-callers/INDEX.md - the mechanism + operator-command -> subfunction mapping
  • SINTRAN/ND500/nd-500-mon/mon60-callers/SUBFUNCTION-TABLE.md - every subfunction 000B-177B with its authoritative purpose and server handler (from the SINTRAN worker source)
  • 101 per-subfunction folders, each with <name>.asm (annotated caller listing), <name>.pseudo.c, and README.md. Eight are named by operator command (LOAD-CONTROL-STORE/, LOAD-SWAPPER/, START-SWAPPER/, STATUS/, START-STANDARD-DOMAIN/, LIST-STANDARD-DOMAINS/, LIST-SYSTEM-PARAMETERS/, LIST-EXECUTION-QUEUE/); the rest are <CODE>B-<MNEMONIC>/.

SINTRAN worker side (the ND-100 resident that services MON 60)

The counterpart carves of the resident SINTRAN worker are under the segment-carver tree:

  • tools/sintran-segment-carver/versions/L-VSX-500/re/mon-analysis/60B-N500M/ - the MON 60 worker handler bodies
  • tools/sintran-segment-carver/versions/L-VSX-500/re/MON-CALL-INDEX.md - master MON-call index
  • tools/sintran-segment-carver/versions/L-VSX-500/re/ND500-HANDLERS-OVERLAY.md - the level-12 ND-500 handlers overlay
  • tools/sintran-segment-carver/versions/L-VSX-500/re/030-S3SM5-routine-map.md - the ND-500 System Monitor routine map

The SUBFUNCTION-TABLE.md purposes come from the worker source SINTRAN/NPL-SOURCE/NPL/5P-P2-MON60.NPL (its 5IFUNC dispatch array).

  • SINTRAN/ND500/swapper/ - the ND-500-side swapper domain the monitor places and starts
  • SINTRAN/ND500/ND500-BUS-INTERFACE-REFERENCE.md - the authoritative 3022/5015 bus-interface reference
  • SINTRAN/ND500/ND500-STATUS-AND-INDEX.md - the ND-500 subsystem status hub

Parent: SINTRAN/ND500/README.md