337B ChangeSegment¶

Stub MON 337B (223 decimal) · Mnemonic SPCHG · Group: RT Program Execution (manual section 2.10)

Available from: RT programs (manual compatibility box)

Emulation source: src/handlers/mon_337B_ChangeSegment.c

Description¶

Changes the segment and the page table your program uses. The monitor call is similar to JumpToSegment and ExitFromSegment. In addition, you may change the two page tables in use. The segment numbers are restricted to 8-bits (values 0-255). SegmentFunction (MON 341) is the equivalent monitor call for version K of SINTRAN III.

Notes¶

You cannot change reentrant segments.

Parameters¶

None.

Compatibility¶

Machines	Users	Programs
ND-100	User RT and user SYSTEM	RT programs

The manual's compatibility box for this call, word for word.

Yes/no fields from the YAML extraction (not in the manual's words):

ND-100	ND-500	User programs	RT programs	System programs
Yes	No	No	Yes	No

Examples¶

From the manual (OCR text, not corrected).

MAC

%Code on initial segment. JumpToSegment is performed.

| Instruction   | Description                                       |
|---------------|---------------------------------------------------|
| SAA 3         | %Page table 1 and 2 in A register.                |
| COPY SA DD    | %Copy to D register.                              |
| LDT (PAR      | %Address of parameter list in T register.         |
| MON 337       | %ChangeSegment with bit 15 in D register = 0.     |
| CONT, ...     | %Execution continues here after ExitFromSegment.  |
| PAR, SUBRO    | %Start address on the new segment.                |
| 100201        | %Segment 200B and 201B.                           |

%Code on new segment. ExitFromSegment is performed.

| Instruction     | Description                                   |
|-----------------|-----------------------------------------------|
| SUBRO, STT SAVET| %Save T, L, and D registers.                  |
| COPY SL DT      |                                               |
| STT SAVEL       |                                               |
| COPY SD DT      |                                               |
| STT SAVED       |                                               |
| ...             |                                               |
| LDT SAVED       | %Restore D register                           |
| COPY ST DD      |                                               |
| BSET ONE DD 170 | %Set bit 15 for ExitFromSegment function.     |
| LDT SAVEL       | %Restore L and T registers.                   |
| COPY ST DL      |                                               |
| LDT SAVET       |                                               |
| MON 337         | %ChangeSegment to return to original segment. |

ndmonlib implementation¶

Stub Registered MON_STATUS_NOT_IMPLEMENTED: the handler is a stub. mon_dispatch() in src/core/mon_dispatch.c reports the call as unimplemented without calling it.


Handler	`mon_337B_ChangeSegment`
Code lines	5 (non-blank, non-comment lines in the file)

Source¶

SINTRAN III Monitor Calls (ND-860228.2 EN), page 107.