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MON 253B (octal) - NewFileVersion (CRALN)

Creates a new version of an existing file (indexed, contiguous, or allocated). You must have directory access to the user area. The version number follows the semicolon in the file name (e.g. TEST:SYMB;4). The file must already exist.

Status: GOTAB dispatch head byte-proven as fall-through (GOTAB[253B] = 000000, no per-call stub); the CRALN worker is real SINTRAN L bytes - the MODE-1 entry of the same shared create/allocate/access/expand dispatcher used by SetFileAccess (237B), whose body lives at 105564B. The exact MON 253 -> worker link crosses an uncarved kernel bridge (see Honest caveats). All addresses/values are octal.

Dispatch path

flowchart LR
    A["User program<br/>MON 253B"] --> B["ENT14 level-14<br/>T = MON number"]
    B --> C["GOTAB[253B] = 000000<br/>(byte-proven: fall-through)"]
    C -.uncarved MFELL / CALLPROC.-> D["CRALN entry<br/>006-S3FS :105560B<br/>SSK=1 SSM=0 = mode 1"]
    D --> E["shared create/alloc/access/expand<br/>dispatcher body<br/>006-S3FS :105564B"]
    class A blue
    class B,C blue
    class D teal
    class E 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 GOTAB slot is zero, so there is no per-call entry stub. The dashed hop (C -> D) is the resident MFELL/CALLPROC fall-through second-level dispatch - not present in any carved segment. CRALN is the mode-1 arm of a shared body it enters by setting the SSK STS flag (and clearing SSM).

Code location (dispatch path)

Every row is a real region you can open. Byte offset is the 006-S3FS.hex byte offset.

Role Segment (full disasm) Addr range (octal) Byte offset Symbol Verdict
GOTAB[253] dispatch word commoncode.asm - .hex 071506B (1 word) 59020 GOTAB+253 = 000000 VERIFIED (fall-through)
resident MFELL/CALLPROC bridge - (uncarved) - - CALLPROC UNVERIFIED
CRALN mode-1 entry 006-S3FS.asm - .hex 105560B-105563B (merge) 48864 CRALN real bytes; link MISATTRIBUTED
shared dispatcher body 006-S3FS.asm - .hex 105564B-106042B (175w) 48872 (shared) real bytes - VERIFIED

Verify by hand: grep '^105560 ' ../../segments-ref/006-S3FS/006-S3FS.hex -> byte offset 48864; then dd if=../../../segments/006-S3FS.bin bs=1 skip=48864 count=4 | od -An -tx1 -> f8 90 a8 02 (= octal 174220 124002 = BSET ONE SSK / JMP 2, the CRALN mode-1 entry; the JMP 2 lands on 105563 BSET ZRO SSM which completes mode 1 before the shared body).

The GOTAB slot itself: dd if=../../../resident/SINTRAN-DATA_commoncode.bin bs=1 skip=59020 count=2 | od -An -tx1 -> 00 00 (= 000000, fall-through).

Instruction walkthrough

Full listing: 253B-NewFileVersion.ASM. There is no F16xx/F17xx stub because GOTAB[253] = 0.

Mode-select entry (105560-105563) - CRALN sets SSK (STS bit2 K) to 1, then 105561 JMP 2 -> 105563 BSET ZRO SSM clears SSM (STS bit7 M), giving MODE = (M<<1)|K = 1, before falling into the shared body at 105564. Its cluster siblings are SFACC (mode 3, SetFileAccess/237B), EXPFI (mode 2, ExpandFile/231B) and CRALF (mode 0).

Prologue + mode rebuild (105564-105574) - 105564 STD I 77 stashes the caller's parameter double-word; 105567 SAB 145 builds the 145-word frame; 105570 JPL I 74 -> 003752 prologue. 105571-105574 rebuild the two STS flags into the 2-bit mode word (M<<1)|K and store it at B+123 (mode 1 for CRALN).

Parameter marshalling (105575-105621) - the caller's file-name pointer and the FirstPage / NoOfPages double-words are copied / address-adjusted into the local frame; 105625 JPL I 51 -> 031075 parses the file name (including the ;version suffix).

Mode dispatch (105627-105657) - 105627 LDA ,B 123 / 105630 SAT 3 / 105631 SKP IF DA LST ST: because CRALN's mode is 1 (< 3), control takes the create / allocate arm at 105641+, which walks the file-name / page arguments through a series of JPL I primitive calls to allocate and register the new version.

Finish (105777-106042) - 105777 MIN ,B 4 bumps the success flag; the epilogue restores caller words and returns through 106007 JMP I 33 -> 106042 = 003776. Error paths funnel through 106010 STA ,B 2 (status -> caller B+2) into the same teardown without the bump.

Parameter / register contract

Reg / field Dir Meaning Verdict
entry point in 105560B = CRALN mode-1 entry (fall-through, no stub) VERIFIED (bytes)
STS K (SSK) internal set by CRALN to select mode 1 (BSET ONE SSK) VERIFIED (bytes)
X (manual) in address of the file-name string (with ;version) inferred (manual MAC example)
D (manual) in FirstPage (start address of first new version; 0 for indexed/contiguous) inferred (manual MAC example)
T (manual) in address of NoOfPages (file size in pages; 0 for indexed) inferred (manual MAC example)
local frame B internal SAB 145 = 145-word working frame VERIFIED (bytes)
B+123 internal 2-bit MODE word (M<<1)|K = 1 (STA ,B 123 at 105574) VERIFIED (bytes)
B+2/B+3 internal FirstPage / NoOfPages working slots VERIFIED (bytes); role inferred
B+2 out returned status word (STA ,B 2 at 106010) VERIFIED (bytes)

The user-visible X/D/T convention lives in the caller-side MON 253 wrapper and the uncarved MFELL/CALLPROC frame, so the precise register-to-argument assignment is inferred from the manual (253B_NewFileVersion.yaml), not byte-proven here.

Pseudo-code (for an emulator)

See 253B-NewFileVersion.pseudo.c - a pseudo-C model of the handler for emulator authors. The mode-select entry, the STS-flag mode rebuild, control flow, and the mode-<3 dispatch are byte-verified; the FirstPage/NoOfPages roles and the identity of the per-mode primitives are inferred.

Every instruction in the model is translated per the canonical ND100-INSTRUCTION-SEMANTICS.md (BSET/BSKP on STS bits M/K; SHA LIN M-bit fill (emulator-authoritative); BSET BAC 0 DA = bit0 from K (emulator-authoritative); SKP IF DA LST ST signed less-than; MIN ,B 4 success bump).

Honest caveats

What is byte-proven: GOTAB[253B] = 000000 (level-14 dispatch, a fall-through with no per-call vector); the CRALN entry at 105560B in 006-S3FS is real code (entry bytes 174220 124002 match the disassembly); it sets K=1 / M=0 and joins the shared body at 105564B, which rebuilds those flags into the 2-bit mode word (M<<1)|K = 1 and dispatches into the create/allocate arm.

What is NOT proven: the link from the zero GOTAB slot to the CRALN entry. Because the vector is zero there is no stub to disassemble and no pointer to dereference; dispatch drops into the resident MFELL/CALLPROC path in an uncarved overlay. So the MON 253 -> CRALN attribution rests on the CRALN symbol name (Create-ALlocate-New), the mode-1 flag pattern, and the matching name+FirstPage+NoOfPages contract, not a followed pointer - hence MISATTRIBUTED in the strict sense.

Shared body: CRALN (253B), SFACC (237B), EXPFI (231B) and CRALF all enter the same dispatcher at 105564B; the ASM and pseudo-C for 237B and 253B therefore share the body and differ only in the entry / selected mode. The create/allocate sub-blocks (105700-105776) are modelled only at the spine.

Region bound: the shared body is bounded to the next symbol SETTF = 106043B; its control flow closes on the 003776 resident-return link cell at 106042. Several link-cell contents (031067, 031075) match no FILSYS-SYMBOLS entry.

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