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MON 245B (octal) - GetNameEntry (GNAEN)

Gets information about a device (disk, floppy, streamer, and so on). The call returns the device's name entry - a 28-byte record with the device name, storage capacity, sector size, device-type flags, transfer-routine address and semaphore LDN. The caller selects the device by its name index (from GetDirNameIndex, MON 243B).

Status: GOTAB dispatch head byte-proven as fall-through (GOTAB[245B] = 000000, no per-call stub); GNAEN is a flag-setting entry that joins a body shared with the sibling calls GDIEN (MON 244B GetDirEntry) and WDIEN (MON 311B WriteDirEntry); with the name-flag set it takes the GNAMA (Get NAme Address) path; the exact MON 245 -> worker link crosses an uncarved kernel bridge (see Honest caveats). All addresses/values are octal.

Dispatch path

flowchart LR
    A["User program<br/>MON 245B"] --> B["ENT14 level-14<br/>T = MON number"]
    B --> C["GOTAB[245B] = 000000<br/>(byte-proven: fall-through)"]
    C -.uncarved MFELL / CALLPROC.-> E["GNAEN name-entry sibling entry<br/>006-S3FS :107114B"]
    E --> G["shared body (with GDIEN/WDIEN)<br/>006-S3FS :107116B"]
    G --> F["GNAMA get-name-address<br/>006-S3FS :30235B"]
    class A blue
    class B,C blue
    class E,G,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

The GOTAB slot is zero, so there is no per-call entry stub. The dashed hop (C -> E) is the resident MFELL/CALLPROC fall-through second-level dispatch - it is not present in any carved segment, so it is the one link that cannot be followed statically.

Code location (dispatch path)

Every row is a real region you can open. Byte offset = (addr - loadbase) in octal words x 2.

Role Segment (full disasm) Addr range (octal) Byte offset Symbol Verdict
GOTAB[245] dispatch word commoncode.asm - .hex 071500B (1 word) 59008 GOTAB+245 = 000000 VERIFIED (fall-through)
resident MFELL/CALLPROC bridge - (uncarved) - - CALLPROC UNVERIFIED
GNAEN name-entry sibling entry 006-S3FS.asm - .hex 107114B-107115B (2w entry) 50328 GNAEN real bytes; link MISATTRIBUTED
shared body (GDIEN/WDIEN/GNAEN) 006-S3FS.asm - .hex 107116B-107400B (to RESDI) 50332 body of GDIEN real bytes
GNAMA get-name-address 006-S3FS.asm - .hex 30235B (call target) - GNAMA called on the name path (link cell 107246) - VERIFIED

Verify by hand: grep '^107114 ' ../../segments-ref/006-S3FS/006-S3FS.hex -> byte offset 50328; then dd if=../../../segments/006-S3FS.bin bs=1 skip=50328 count=8 | od -An -tx1 -> f8 90 f8 38 22 4a cc 65 (= octal 174220 174070 021112 146145 = BSET ONE SSK / BSET ZRO SSM / STD I 112 / RADD CLD SL DA, the GNAEN entry and the joined shared body head at 107116).

The GOTAB slot itself: dd if=../../../resident/SINTRAN-DATA_commoncode.bin bs=1 skip=59008 count=2 | od -An -tx1 -> 00 00 (= 000000, fall-through).

The GNAMA link cell: dd if=../../../segments/006-S3FS.bin bs=1 skip=50508 count=2 | od -An -tx1 -> 30 9d (= octal 030235, the word at 107246B = the resolved GNAMA worker address).

Instruction walkthrough

Full listing: 245B-GetNameEntry.ASM. GNAEN is a 2-word flag-setting entry into a body shared with two siblings; the shared body is the same bytes documented for MON 244B GetDirEntry.

  • GNAEN entry / flag set (107114-107115) - 107114 BSET ONE SSK sets the name flag (SSK=1, name entry rather than directory entry) and 107115 BSET ZRO SSM clears the write flag (SSM=0, get rather than write), then control falls into the shared body at 107116. The sibling entries are GDIEN (107111, SSK=0/SSM=0, MON 244B) and WDIEN (107106, SSM=1, MON 311B).
  • Entry prologue (107116-107122) - 107116 STD I 112 stashes the caller's double-word parameter; 107121 SAB 106 builds the 106-word local frame B; 107122 JPL I 107 -> 003752 is the shared resident prologue worker.
  • Flag latch + name path (107123-107221) - the flags are latched into B+104 (write) and B+105 (name); with the name flag set the body takes 107217 JPL I 27 -> 030235 (GNAMA, Get NAme Address) rather than the directory path 107213 JPL I 31 -> 030225 (GDIRA). A range/validity failure loads error 174 (107226 SAA 174) and exits.
  • Format + finish (107250-107365) - the name entry is formatted into the caller's buffer via the resident / SUCPB / GNFLA workers; 107364 STA ,B 2 writes the result word into the caller's status slot B+2; every path funnels into the resident return 107362 JMP I 16 -> 003776.

The JPL I 27 call to GNAMA (link cell 107246 = 030235) on the name path is the byte-level proof that GNAEN is the GetNameEntry worker: SSK=1 selects the get-name-address primitive that yields the device name entry. GNAEN is also the 245B short name in the manual.

Parameter / register contract

Manual-side names/types are from 245B_GetNameEntry.yaml.

Reg / field Dir Meaning Verdict
entry point (sibling) in 107114B = GNAEN (SSK=1/SSM=0), joins shared body at 107116B VERIFIED (bytes)
SSK (skip flag) internal 1 at GNAEN entry = name entry (not directory); latched to B+105 VERIFIED (bytes)
SSM (skip flag) internal 0 at GNAEN entry = get (not write); latched to B+104 VERIFIED (bytes)
D (double) in caller parameter block, saved first (STD I 112) VERIFIED (copy); layout inferred
local frame B internal SAB 106 = 106B-word working frame VERIFIED (bytes)
T (manual) in name index of the device (LDT NAMIX) inferred (manual MAC example)
X (manual) in address of the 14-word (28-byte) buffer receiving the name entry inferred (manual)
A (manual) out error number on the error return inferred (manual)
error 174 out address/validity error literal (SAA 174 at 107226) VERIFIED (bytes); mapping inferred
B+2 out returned status word (STA ,B 2 at 107364) VERIFIED (bytes)

The user-visible T/X register convention lives in the caller-side MON 245 wrapper and the uncarved MFELL/CALLPROC frame, so the precise user-register-to-field assignment is inferred from the manual, not byte-proven here.

Pseudo-code (for an emulator)

See 245B-GetNameEntry.pseudo.c - a pseudo-C model of the handler for emulator authors. The SSK/SSM flag set and the name-path call to GNAMA are byte-verified; the parameter-field semantics and error-number meanings are inferred from the call structure and the manual. Every instruction is translated per the canonical ND100-INSTRUCTION-SEMANTICS.md (BSET ONE/ZRO SSx sets/clears the skip flag; BSKP ONE SSx tests it; MIN ,B 4 success bump).

Honest caveats

What is byte-proven: GOTAB[245B] = 000000 (level-14 fall-through, no per-call vector); the GNAEN entry at 107114B in 006-S3FS is real code (entry bytes 174220 174070 021112 146145 match the disassembly); it sets SSK=1/SSM=0 and joins a body shared with GDIEN (MON 244B) and WDIEN (MON 311B) at 107116B, bounded by the next FILSYS symbol RESDI = 107401B; and on the name path it calls GNAMA (030235B, link cell 107246).

What is NOT proven: the link from the zero GOTAB slot to the GNAEN entry. Because the vector is zero there is no stub to disassemble and no pointer to dereference; dispatch drops into the resident MFELL/CALLPROC second-level path, which lives in an uncarved overlay. So the MON 245 -> GNAEN attribution rests on the GNAEN symbol name (the 245B short name) + its GNAMA name-path call + the matching name-entry behaviour, not a followed pointer - hence MISATTRIBUTED in the strict sense. Confirming the link needs a live trace: issue a real MON 245, single-step the level-14 fall-through into the resident CALLPROC dispatch, and confirm P lands on GNAEN = 107114.

Shared body: GNAEN, GDIEN (107111B, MON 244B) and WDIEN (107106B, MON 311B) are three entries into one body that forks on the SSK/SSM flags. The body is shown here for context; the GetNameEntry-specific behaviour is the name path selected by SSK=1. Several link-cell targets (003752, 020274, 001224, 010500, 010506, 003776) sit below the 26000B segment load base; they are resident-monitor / save-restore routines outside the file-system segment and are not resolved here.

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