Memory management in MDOS is available via XOP 7. In the MDOS sources the relevant files are manage2s and manage2t.
General purpose XOPs
Error codes:
| Code
|
Meaning
|
| 00
|
No error
|
| 01
|
not enough free pages
|
| 02
|
can't remap execution page zero
|
| 03
|
no page at LOCAL address
|
| 04
|
user area not large enough for list
|
| 05
|
shared type already defined
|
| 06
|
shared type doesn't exist
|
| 07
|
can't overlay shared and private memory
|
| 08
|
out of table space
|
Return number of free pages in system
Opcode: 0
|
|
Input |
Output
|
| R0
|
Opcode (0000) |
Error code (always 0)
|
| R1
|
|
Number of free pages
|
| R2
|
|
Number of fast free pages
|
| R3
|
|
Total number of pages in system
|
Claim pages into local map from free pages
Opcode: 1
|
|
Input |
Output
|
| R0
|
Opcode (0001) |
Error code
|
| R1
|
Number of pages |
Number of pages actually fetched to complete map as required
|
| R2
|
Local page address |
Number of fast pages fetched
|
| R3
|
Speed flag (if not 0, only fast) |
|
Return pages into free pool from local map
Opcode: 2
|
|
Input |
Output
|
| R0
|
Opcode (0002) |
Error code
|
| R1
|
Number of pages |
|
| R2
|
Local page address |
|
Map local page at excution page
Opcode: 3
|
|
Input |
Output
|
| R0
|
Opcode (0003) |
Error code
|
| R1
|
Local page number |
|
| R2
|
Execution page number |
|
Get address map
Opcode: 4
|
|
Input |
Output
|
| R0
|
Opcode (0004) |
Error code
|
| R1
|
Pointer to buffer |
Count of pages reported
|
| R2
|
Size of area for map |
|
Declare shared pages
Opcode: 5
|
|
Input |
Output
|
| R0
|
Opcode (0005) |
Error code
|
| R1
|
Number of pages to declare as shared |
|
| R2
|
Local page address |
|
| R3
|
Type to be assigned to shared pages |
|
Release shared pages (type)
Opcode: 6
|
|
Input |
Output
|
| R0
|
Opcode (0006) |
Error code
|
| R1
|
Type |
|
Also have to check their current execution map
Get shared pages
Opcode: 7
|
|
Input |
Output
|
| R0
|
Opcode (0007) |
Error code
|
| R1
|
Type |
|
| R2
|
Local page number for start of shared area |
|
Return size of shared page group
Opcode: 8
|
|
Input |
Output
|
| R0
|
Opcode (0008) |
Error code
|
| R1
|
Type |
Number of pages in shared group
|
Privileged XOPs (only available for operating system)
Release task
Opcode: 9
|
|
Input |
Output
|
| R0
|
Opcode (0009) |
|
Task header at >8000
Page get
Opcode: 10
|
|
Input |
Output
|
| R0
|
Opcode (000A) |
Error code
|
| R1
|
Page number to get (if high byte not 0, get first available) |
Pointer to node
|
| R2
|
Speed flag (if not 0, only fast) |
Page number from node
|
Add page to free pages in system
Opcode: 11
|
|
Input |
Output
|
| R0
|
Opcode (000B) |
Error code (if no free nodes available)
|
| R1
|
Page number |
Pointer to node
|
Add a node to the list of free nodes
Opcode: 12
|
|
Input |
Output
|
| R0
|
Opcode (000C) |
Error code (always 0000)
|
| R1
|
Pointer to node |
|
Link a node to the specified node
Opcode: 13
|
|
Input |
Output
|
| R0
|
Opcode (000D) |
Error code (always 0000)
|
| R1
|
Pointer to node |
|
| R2
|
Pointer to node to link to |
|
Get address map (system)
Opcode: 14
|
|
Input |
Output
|
| R0
|
Opcode (000E) |
Count of valid pages
|