The virtual subarea list provides the basic input to the page service functions that use a 24-bit interface: PGLOAD, PGRLSE, and PGOUT. The list consists of one or more doubleword entries, each entry describing an area of virtual storage. The list must be non-pageable and contained in the address space of the subarea to be processed.
Each subarea list entry has the format shown below. The flag bits that are described are the only flag bits intended for customer use.
| Byte | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|---|
| FLAGS | START |
FLAGS | END |
| Byte 0 Flags: | ||
|---|---|---|
Bit 0 |
(1... ....) |
This bit indicates that bytes 1-3 are a chain pointer to the next VSL entry to be processed; bytes 4-7 are ignored. This feature allows several parameter lists to be chained as a single logical parameter list. |
| Start Address: The address of the origin of the virtual area to be processed. |
||
| Byte 4 Flags: | ||
| Bit 0 | (1... ....) | This flag indicates the last entry of the list. It is set in the last doubleword entry in the list. |
| Bit 1 | (.1.. ....) | When this flag is set, the entry in which it is set is ignored. |
| Bit 3 | (...1 ....) | This flag indicates that a return code of 4 was issued from a page service function other than PGRLSE. |
| End Address + 1: The address of the byte immediately following the end of the virtual area. |