OS_DynamicArea 25 (changes)
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OS_DynamicArea
» OS_DynamicArea 25
OS_DynamicArea 25
(SWI &66)
| Entry | |
|---|---|
| R0 | |
| R1 | Area number |
| R2 | Pointer to input/output page list |
| R3 | Number of entries in page list |
| Exit | |
|---|---|
| - | All registers preserved |
| Page list updated |
Use
This call is used to query the status of pages within a Physical Memory Pool.
Notes
Each entry in the page list is 16 bytes in length, structured as follows:
| Word | |
|---|---|
| 0 | PMP page index |
| 1 | Physical page number |
| 2 | Dynamic area page number |
| 3 | Page flags: |
| Bits 0-5, 12-14: As per Memory Page Access Flags | |
| Bit 15: Page is locked to prevent it from being claimed by another dynamic area | |
| Other bits: Reserved |
On entry, for each array entry either the PMP page index, phys page number, or DA page number must be provided, with the other page numbers set to -1. Page flags are ignored.
On exit, if the page is a member of the PMP, the entries will be filled in as appropriate. If the page isn’t mapped in (and it was a lookup by PMP page index/phys page number) the DA page index will be set to -1. If no physical page is allocated (or the indicated page isn’t a member of the PMP) the page flags will be set to 0.
See also
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