GeneveOS Memory Management Functions

Memory management in MDOS is available via XOP 7.

General purpose XOPs

opcode #0, return number of free pages in system
     after return: r0=ERROR CODE (always zero)
                   r1=number of free pages
                   r2=number of fast free pages 

opcode #1, claim pages into local map from free pages
     pass:             r1=number of pages
                       r2=local page address
                       r3=speed flag <>0 means FAST
     return:           r0=error code
                       r1=number of pages actually fetched
                            to complete map as required
                       r2=number of fast pages fetched

opcode #2, return pages into free pool from local map
     pass:             r1=number of pages
                       r2=local page address
     return:           r0=error code

opcode #3, map local page at excution page
     pass:             r1=local page number
                       r2=execution page number
     return:           r0=error code

opcode #4, get address map
     pass:             r1=execution address
                       r2=size of area for map
     return:           r0=error code
                       r1=count of pages reported

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)

opcode #9 : release task    in: nil        (task header at >8000)
                            out: nil

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

opcode #B : add page to free pages in system
              in:      r0=>000B
                       r1=page number
             out:      r0= error if no free nodes available

opcode #C : add a node to the list of free nodes
              in:      r0=>000C
                       r1=pointer to node
             out:   no errors

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

opcode #E, get address map  (system)
     return:           R0= count of valid pages