GeneveOS Memory Management Functions
Memory management in MDOS is available via XOP 7.
General purpose XOPs
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 |
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 (0 is slow, else 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 | Execution address | Count of pages reported |
| R2 | Size of area for map |
opcode #5, declare shared pages
pass: r1=number of pages to declare as shared
r2=local page address
r3=type to be assigned to shared pages
return: r0=error code
opcode #6, release shared pages (type)
pass: r1=type
return: r0=error code
also have to check their current execution map
opcode #7, get shared pages
pass: r1=type
r2=local page number for start of shared area
return: r0=error code
opcode #8, return size of shared page group
pass: r1=type
return: r0=error code
r1=number of pages in shared group
Privileged XOPs (only available for operating system)
Release task
opcode #9 : release task in: nil (task header at >8000)
out: nil
Page get
opcode #A : page get in: r0=>000A
r1=page number to get,
if r1h <> 0, get first available
r2=speed flag <>0 means fast
out: r0=error code
r1=pointer to node
r2=page number from node
Add page to free pages in system
opcode #B : add page to free pages in system
in: r0=>000B
r1=page number
out: r0= error if no free nodes available
Add a node to the list of free nodes
opcode #C : add a node to the list of free nodes
in: r0=>000C
r1=pointer to node
out: no errors
Link a node to the specified node
opcode #D : link a node to the specified node
in: r0=>000D
r1=pointer to node
r2=pointer to node to link to
out: no errors
Get address map (system)
opcode #E, get address map (system)
return: R0= count of valid pages