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MON 114B (octal) - TUSED (GetTimeUsed)

Returns the CPU time the caller has used since login (for a batch job, the time since the job started). The worker TUSED is carved in 003-S3CP. All addresses/values are octal.

Status: byte-verified (dispatch chain + worker entry). The worker is real carved code in 003-S3CP.

CORRECTED 2026-07-13. Earlier versions of this folder used the disproven dispatch model (GOTAB as the monitor-call table, an "uncarved CALLPROC bridge"). MON calls dispatch through MCTAB @ 005620B (segment 044-S3IDPIT), not GOTAB (which is MFELL for 224 of 256 calls). MCTAB[114B] = 041303B = TUSED, carved in 003-S3CP. See ../317B-ExecuteCommand/README.md and SINTRAN/CARVING-HANDOFF.md section 3a.

Dispatch path

flowchart LR
    A["User program<br/>MON 114B"] --> B["ENT14 level-14 entry<br/>026-S3IMPIT :072167B"]
    B --> C["GOTAB[114B] = MFELL<br/>MGOTA=071233B :071347B"]
    C --> D["MFELL level switch<br/>026-S3IMPIT :072114B -> CALLP 032201B"]
    D --> E["MCTAB[114B] = TUSED<br/>MCTAB=005620B :005734B = 041303B"]
    E --> F["TUSED worker<br/>003-S3CP :041303B"]
    class A blue
    class B,C,D,E teal
    class F 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

Code location (dispatch path)

Byte offset = (addr - loadbase) in octal words x 2 (decimal). Every offset was reproduced with dd.

Role Segment Addr (octal) Byte offset Symbol Verdict
GOTAB[114B] slot 026-S3IMPIT.asm 071347B = 072114B 32206 -> MFELL VERIFIED
MFELL level switch 026-S3IMPIT.asm 072114B 32920 MFELL VERIFIED
MCTAB[114B] slot 044-S3IDPIT.asm 005734B = 041303B 1976 -> TUSED VERIFIED
TUSED worker body 003-S3CP.asm 041303B-041373B 9606 TUSED VERIFIED

Verify by hand (from tools/sintran-segment-carver/versions/L-VSX-500/segments/): 

dd if=026-S3IMPIT.bin bs=1 skip=32206 count=2 | od -An -tx1   ->  74 4c   (= 072114B = MFELL)
dd if=044-S3IDPIT.bin bs=1 skip=1976  count=2 | od -An -tx1   ->  42 c3   (= 041303B = TUSED)
dd if=003-S3CP.bin    bs=1 skip=9606  count=2 | od -An -tx1   ->  c4 35   (= 142065B, TUSED entry word)

Instruction walkthrough

Full listing: 114B-GetTimeUsed.ASM.

Entry / arg check (041303B-041306B). 142065 SKP IF DA UEQ ST compares A against T and, on failure, 170547 SAA 147 loads an error code and 125146 JMP I 146 (-> 041454B) takes the error/return path.

Selector decode (041307B-041366B). 146157 RADD CLD SA DX moves the selector into X, 052012 LDT ,X 12 / 010602 STT ,B -176 stage a field, then 054143 LDX 143 / 135143 JPL I 143 (-> 041456B) calls a helper. The body is a multi-way selector (sub-symbols 1NOTO, XSBPR, 1FU2, 1FU3, STERM, 1FU4, 1FU5) each of which loads a table pointer (LDX 136/133...) and calls the helper at 041456B, returning via 125742 JMP I ,B -36. A section brackets a critical read with 150401 IOF / 150402 ION (interrupts off/on) while sampling the accounting field (046003 LDA ,X 3).

The routine reads a per-process CPU-time accounting field and returns the time used; the exact field offsets and the sub-function set are inferred from structure, the control flow and the IOF/ION-guarded read are byte-proven.

Parameter / register contract

Reg / field Dir Meaning Verdict
A,T in argument checked at entry (SKP IF DA UEQ ST); mismatch -> error 147 VERIFIED (bytes); meaning inferred
,B -176 frame staged field (STT ,B -176) VERIFIED (bytes)
accounting field in per-process CPU-time read under IOF/ION guard (LDA ,X 3) VERIFIED (bytes); field offset inferred
result out CPU time used since login / job start VERIFIED (manual); packing inferred

Pseudo-code (for an emulator)

See 114B-GetTimeUsed.pseudo.c. The arg check, the selector decode and the interrupt-guarded accounting read are byte-verified; the field offsets and the exact sub-function semantics are inferred.

Honest caveats

What is byte-proven: the full dispatch chain - GOTAB[114B] = MFELL, MFELL switches program level to CALLP, MCTAB[114B] = TUSED = 041303B, and the TUSED entry bytes at 041303B in 003-S3CP match the disassembly. The routine range-checks an argument, decodes a multi-way selector and reads a per-process accounting field under an IOF/ION guard.

What is NOT proven: the exact accounting-field layout, the meaning of each sub-function (1FU2..1FU5 etc.), and the result packing. Those are inferred from structure and the manual.

Method: ../../../../../EXTRACTING-RESIDENT-CODE.md · master map: ../../MON-CALL-INDEX.md.