Skip to content

MON 514B (octal) - ND500TimeOut (M5TMOUT / M5TMO)

Suspends the calling ND-500 program for a given time; the program is placed in a time queue inside the ND-500 (not the ND-100) and its execution resumes after the delay. NPL/handler name M5TMOUT; the L symbol table names the entry M5TMO=140563B. All addresses/values are octal.

Status: handler identity byte-proven (real SINTRAN L bytes at M5TMO=140563B in 026-S3IMPIT, load 32000B). Every indirect worker pointer resolves 1:1 to the M5TMOUT worker set (SLOCK, SUNLOCK, XTER500, SPITMQ, IFM500XQ, WN5STATUS, EMONICO, XACTRDY, NXTMSG), and the call/exit sequence matches the NPL M5TMOUT routine structure (a different revision, whose addresses sit ~200B lower). The MON 514B -> M5TMOUT dispatch crosses an uncarved level-12 GOSW table, so that one link stays UNVERIFIED (see Honest caveats).

Dispatch path

MON 514B is an ND-500 level-12 monitor call. It is not dispatched through the ND-100 monitor GOTAB - a GOTAB[514] probe is meaningless. It arrives at the handler via the resident level-12 GOSW, slot 14 octal (M5TMOUT) of the 5CMNO-L12MIN GOSW (base 500B; 514B - 500B = 14 octal = index 12 decimal in the 0-indexed name list).

flowchart TD
    A["ND-500 process<br/>MON 514B"] --> B["stop MOCALL, level-12"]
    B --> C["MCHANDEL reads<br/>MCNO = 514B"]
    C -.uncarved level-12 GOSW.-> E["5CMNO / L12MIN GOSW<br/>slot 14 octal = M5TMOUT"]
    E --> F["M5TMO handler body<br/>026-S3IMPIT :140563B"]
    F --> G["exit: EMONICO / XACTRDY<br/>or NXTMSG (135067B)"]
    class A blue
    class B,C,E teal
    class F,G green
    classDef blue fill:#E3F2FD,stroke:#0D47A1,color:#0D47A1
    classDef teal fill:#E0F7FA,stroke:#00838F,color:#00838F
    classDef green fill:#E8F5E9,stroke:#2E7D32,color:#2E7D32

The dashed hop (C -> E) is the resident level-12 GOSW (5CMNO-L12MIN, slot 14 octal) - it is not present in any carved segment, so it is the one link that cannot be followed statically. The GOSW-slot-14 -> M5TMOUT mapping is VERIFIED from NPL (MP-P2-N500.NPL lines 1385-1389: ... B5XMSG, M5TMOUT, 5MTRANS, ..., the 13th name = index 12 decimal = slot 14 octal); the runtime dispatch remains UNVERIFIED because the GOSW overlay is uncarved.

Code location (dispatch path)

Every row is a real region you can open. Byte offset = (addr - loadbase) in octal words x 2 (decimal). Handler load base = 32000B.

Role Segment (full disasm) Addr range (octal) Byte offset Symbol Verdict
GOTAB[514] probe - (ND-500 call, not GOTAB-dispatched) - - (none) MISATTRIBUTED - a GOTAB[514] probe is meaningless for a level-12 call
Level-12 GOSW dispatch - (uncarved resident level-12) MCHANDEL reads MCNO=514B; 5CMNO-L12MIN slot 14 octal - 5CMNO / L12MIN -> M5TMOUT UNVERIFIED - dispatch mechanism, not carved
Timeout entry 026-S3IMPIT.asm · .hex 140563B 72422 M5TMO=140563B VERIFIED
Restart-reason tag 026-S3IMPIT.asm · .hex 140600B 72448 NNT11=140600B VERIFIED (byte; internal continuation tag)
Queue-link tags 026-S3IMPIT.asm · .hex 140712B / 140763B / 141005B 72596 / 72678 / 72714 NNC16 / NNC17 / NNC18 VERIFIED (byte; internal tags reached by the body's own flow)
Handler body (closure) 026-S3IMPIT.asm · .hex 140563B-141026B (164 words) 72422 M5TMO .. pool end VERIFIED (self-contained control flow)
Next distinct handler 026-S3IMPIT.asm · .hex 141027B 72750 NOUTS/DVIO=141027B (MON 504B) VERIFIED (excluded from this carve)

Verify by hand: grep '^140563 ' ../../segments-ref/026-S3IMPIT/026-S3IMPIT.hex -> byte offset 72422; then dd if=../../../segments/026-S3IMPIT.bin bs=1 skip=72422 count=8 | od -An -tx1 -> ba 67 c9 00 52 66 f7 ff (= octal 135147 144400 051146 173777, the M5TMO entry JPL I 147 (-> SLOCK) / RAND 0 0 / LDT I 146 / AAX -1).

Instruction walkthrough

Full listing: 514B-ND500TimeOut.ASM. The 164-word window is one self-contained routine (control-flow closure confirmed - all 13 direct branches land inside 140563B..140773B). Two embedded pointer/parameter pools the disassembler mis-renders as instructions are DATA, not code: 140732B..140752B (jumped over by 140731 JMP -> 140753) and 141022B..141026B.

Indirect worker pointers, resolved against L07 symbols - the identity proof. Each pointer word resolves one-to-one to the M5TMOUT worker set (the same calls, in the same order, as the NPL M5TMOUT routine):

Ptr word Value Symbol (L07, 5-char) Worker
140732 023706 SLOCK SLOCK - take the ND-500 driver lock
140734 024041 SUNLO SUNLOCK - release the driver lock
140736 145372 XTER5 XTER500 - terminate/clear ND-500 timer (role inferred)
140737 023320 SPITM SPITMQ - set restart reason into queue (role inferred)
140740 145466 XACTR XACTRDY - reactivate ND-500 executor queue
140741 135067 NXTMS NXTMSG - handle next ND-500 message (exit)
140742 023021 EMONI EMONICO - restart ND-500 proc with error
140745 022704 IFM50 IFM500XQ - fix proc into ND-500 time queue (role inferred)
140746 023670 WN5ST WN5STATUS - write ND-500 process status

Entry + repeat check (140563..140605). 140563 JPL I -> SLOCK takes the ND-500 driver lock. 140565..140571 load the message flag word (LDT I 146 / AAX -1 / LDATX, NPL 5MSFL) and test the repeat bit (BSKP ONE 170). If set, 140572..140575 clear the bit, JPL I -> SUNLOCK, and set the restart reason (SAA -1), then fall into the restart-reason block at NNT11=140600 (XTER500 / SPITMQ / XACTRDY / JMP I -> NXTMSG).

Parameter validation (140606..140667). 140606 JPL I -> SUNLOCK; then the number-of-time-units parameter is read from the message buffer (NPL 5ADP1). The illegal-parameter branch 140614..140620 loads SAA 174 (error 174) and leaves via EMONICO / XACTRDY / JMP I -> NXTMSG. A zero count restarts immediately (NPL IF D=0 GO N5TMF). 140623..140632 read and validate the time-unit selector (1..4); 140633..140667 convert the requested delay into basic time units (the SAT/SHA/RADD ladder; exact arithmetic inferred).

Time-queue insertion (140670..141021). 140670 JPL I -> SLOCK re-takes the lock; 140672 JPL I -> IFM500XQ fixes the process into the ND-500 time queue; 140674 JPL I -> WN5STATUS writes the process status. The continuation tags NNC16=140712 / NNC17=140763 / NNC18=141005 link the entry into the sorted queue (byte-address <-> word-address conversions; layout inferred). 141020 JPL I -> SUNLOCK releases the lock and 141021 JMP I -> NXTMSG exits - the ND-500 process stays suspended until its queued restart time.

Parameter / register contract

ND-500 monitor calls pass parameters in the ND-500 message buffer (indexed by 5MBBANK + field displacement), not in ND-100 A/T/X user registers. The register use below is level-12 driver-internal. NPL entry (a different revision, so inferred here): X = current message, B = ND-500 CPU datafield.

Item Dir Meaning Verdict
X / B (entry) in current message / ND-500 CPU datafield inferred (NPL M5TMOUT header; not byte-isolated)
message flag 5MSFL (msg) in carries the repeat bit 55REP inferred (read at 140565..140571; field displacement UNVERIFIED)
NoOfTimeUnits (msg) in number of time units to suspend (0 = restart now) inferred (read via 5ADP1; exact field UNVERIFIED)
TimeUnit (msg) in 1=1/50 s, 2=s, 3=min, 4=hour inferred (validated 1..4 at 140623..140632; NPL/reference manual)
ReturnStatus (msg) out restart cause: 0=elapsed, 1=interrupt, -1=repeat inferred (reference manual; SAA -1 repeat reason is byte-visible)
Error 174 (EC174) out illegal parameter -> EMONICO VERIFIED (SAA 174 byte)
Exit out EMONICO/XACTRDY (error/restart) or NXTMSG (queued) VERIFIED (indirect ptrs resolve)
Skip-return - none in the ND-100 sense; control leaves via the workers above VERIFIED (none in-window)

Pseudo-code (for an emulator)

See 514B-ND500TimeOut.pseudo.c - a pseudo-C model of the timeout/suspend worker for emulator authors. Control flow, the nine indirect worker pointers (SLOCK, SUNLOCK, XTER500, SPITMQ, IFM500XQ, WN5STATUS, EMONICO, XACTRDY, NXTMSG), and the SAA 174 error path are byte-verified; the time-unit conversion arithmetic and the message-field layout are inferred from the code structure and the NPL M5TMOUT routine (a different revision than L). ND-500 parameters are passed in the ND-500 message buffer, not in A/T/X.

Every instruction is translated per ../../instruction-semantics/ND100-INSTRUCTION-SEMANTICS.md (the authoritative ND-100 semantics reference). The handler reads and writes that message buffer with the T/X physical transfers LDATX / STATX / LDDTX / STDTX: these form a 24-bit PHYSICAL address EL = ((T & 0377) << 16) | ((X + disp3) & 0177777) where T is the memory bank (the ND-500 message-buffer bank 5MBBANK) and X the word offset - the access bypasses the MMU / page tables (reference section 5). disp3 = 0 here because the code pre-adjusts X with AAX.

Honest caveats

What is byte-proven: the handler at M5TMO=140563B is real SINTRAN L code carved from 026-S3IMPIT (load 32000B). Two independent anchors agree: (1) M5TMO=140563 in the L07 symbol table (SYMBOL-2-LIST), and (2) every indirect worker pointer resolves to exactly the M5TMOUT worker set (SLOCK, SUNLOCK, XTER500, SPITMQ, IFM500XQ, WN5STATUS, EMONICO, XACTRDY, NXTMSG) called in the same order as the NPL M5TMOUT routine. The illegal-parameter error path (SAA 174 -> EMONICO) is byte-verified. The carved slice is byte-identical to the canonical segment (dd above reproduces the entry words).

Closure note (why the window is 140563..141026). All 13 direct branches (JMP -24 -> 140576, JAZ -> 140621, JMP 22 -> 140753, etc.) land inside 140563B..140773B. The internal continuation tags NNT11=140600, NNC16=140712, NNC17=140763, NNC18=141005 are this routine's own labels (they match the NPL M5TMOUT internal *NNT11=* / *NNC16, / *NNC17, / *NNC18, markers), not separate handlers. The genuinely next handler, NOUTS/DVIO=141027B (MON 504B OutputString), is excluded. Closing the control flow to 141026 includes this routine's body plus its two trailing pointer pools without swallowing a foreign routine. validate-mon-carves.py confirms SIZE/CONTIG/CLOSURE with zero direct escapes.

What is NOT proven: - The dispatch. MON 514B is an ND-500 level-12 call; it is not in GOTAB (a GOTAB[514] probe is meaningless). The real path is the resident level-12 GOSW (MCHANDEL reads MCNO, 5CMNO-L12MIN slot 14 octal = M5TMOUT), which is in an uncarved overlay and cannot be followed statically. The GOSW-slot-14 -> M5TMOUT mapping is VERIFIED from NPL; the runtime arrival is UNVERIFIED. - The exact parameter fields. The message-flag/repeat-bit displacement, the NoOfTimeUnits (5ADP1) and TimeUnit (5ADP2) fields, and the ReturnStatus write-back are read from the ND-500 message buffer whose exact displacements are not byte-isolated in this window - marked inferred. - The time arithmetic. The convert-to-basic-time-units ladder and the sorted time-queue insertion (NNC16/NNC17/NNC18) are structurally matched to the NPL but not independently byte-decoded field by field - inferred. - NPL is a different revision than L. NPL places M5TMOUT at 140363B (~200B lower) and the L bytes place M5TMO=140563B; only the behaviour, tag names, and worker call order carry over - the worker names were re-verified against the L07 pointer words above.

Confirming the full chain needs a live trace (break at the level-12 GOSW on a real ND-500 MON 514B, single-step, confirm P lands on M5TMO=140563).

Method: ../../../../../EXTRACTING-RESIDENT-CODE.md §7.6/7.7 · dispatch reality: ../../TASK-05-mismatches.md · master map: ../../MON-CALL-INDEX.md.