; --------------------------------------------
; Title:   DCOS - Kernel - Memory Management
; Author:  Kieron
; Date:    25/04/2012
; Version:
; --------------------------------------------

:DCOS_RAM_RESERVE ;Reserve Kernal Memory
                 JSR REG_CLEAR

                 SET A, [LDTXT]
                 BOR A, 0x7000
                 SET I, A
                 SET J, 0
                 SET Z, 0x8000

                 SET C, POP
                 SET X, POP
                 SET B, POP
                 SET A, POP

:RESLOOP
                IFE [a], 0x0
                SET [a], X
                ADD A, 1
                IFG B, A
                SET PC, RESLOOP
SET PC, C

;#

:DCOS_MEMBLOCK_ALLOCATE ;Allocate Memory to a Guest
                       JSR REG_CLEAR
                       SET A, 0x3801
                       SET B, 0x1
                       :MAT_LOOKUP ;Loop round the Memory Allocation Table
                                  IFE [A], 0x1B58
                        SET PC, MAT_ALLOCATE
                                  ADD B, 0x1
                                  ADD A, 0x3
                       SET PC, MAT_LOOKUP

                       :MAT_ALLOCATE ;Allocate a new slot
                                    SET [A], B

                                    IFE B, 1
                        SET PC, MAT_ALLOCATE_FIRST
                                    SET PC, MAT_ALLOCATE_NEW

                                    :MAT_ALLOCATE_FIRST ;First Guest
                                    SET C, 0x3B02
                                    SET PC, CHECK_MEMORY_AVAILABILITY

                                    :MAT_ALLOCATE_NEW ;New Guest
                                    SUB A, 0x1
                                    SET C, [A]
                                    ADD C, 0x1
                                    ADD A, 0x1

                                    :CHECK_MEMORY_AVAILABILITY ;Check for a 256 Chunk
                                    SET X, 0x1
                                    SET Y, 0x0
                                    SET J, C

                                    :MEMORY_FREE_LOOP ;Loop through memory based on MAT
                                                      IFG J, 0x7000
                                                          IFG 0x9010, J
                                                              SET PC, MEMORY_RESERVE_OVERRUN
                                                      IFG J, SP
                                                          SET PC, MEMORY_STACK_OVERRUN
                                                      IFG [J], 0x0
                                SET PC, MEMORY_RELOCATE
                                                      IFE X, 0x100
                                SET PC, MEMORY_USABLE
                                                      ADD J, 1
                                                      ADD X, 1
                                    SET PC, MEMORY_FREE_LOOP


                                    :MEMORY_RESERVE_OVERRUN
                                                           SET C, 0x9010
                                    SET PC, CHECK_MEMORY_AVAILABILITY


                                    :MEMORY_STACK_OVERRUN
                                                         SET [A], 0x1B58
                                                         JSR REG_CLEAR
                                                         SET J, 1
                                                         JSR CPU_HANG
                                    SET PC, POP


                                    :MEMORY_RELOCATE ;Start a new search (Last check not free)
                                                    ADD J, 0x1
                                                    SET C, J
                                    SET PC, CHECK_MEMORY_AVAILABILITY


                                    :MEMORY_USABLE ;Add Used address range to MAT
                                                  ADD A, 0x1
                                                  SET [A], C
                                                  ADD A, 0x1
                                                  ADD C, 0x100
                                                  SET [A], C
                                                  SUB A, 0x2
                       :MEMORY_WRITE ;Write Guest Number & 7000 Reserve to Allocated Memory
                       SET PUSH, A
                       JSR REG_CLEAR
                       SET A, POP
                       SET B, [A]
                       ADD A, 0x1
                       SET C, [A]
                       SET [C], B
                       ADD A, 0x1
                       SET C, [A]
                       SET [C], 0x1B58
                       SUB C, 0x1
                       SET [C], 0x1B58
                       JSR REG_CLEAR
SET PC, POP

;#

:DCOS_MEMBLOCK_EXTEND

SET PC, POP

;#

:DCOS_MEMBLOCK_FREE
                   JSR REG_CLEAR
                   SET J, POP
                   SET A, POP
                   SET I, 0x37FE
                   SET Y, 3
                   MUL Y, A
                   ADD I, Y
                   :FREE_MEM
                            SET [I], 0x1B58
                            ADD I, 0x1
                            SET B, [I]
                            SET [I], 0x1B58
                            ADD I, 0x1
                            SET C, [I]
                            SET [I], 0x1B58
                            ADD C, 0x1
                            :FREE_ALLOCATION
                            SET [B], 0x0
                            ADD B, 1
                            IFG C, B
                    SET PC, FREE_ALLOCATION
SET PC, J