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NAME
- AllocEntry
-
allocate many regions of memory
SYNOPSIS
memList = AllocEntry(memList)
D0 A0
struct MemList *AllocEntry(struct MemList *);
D0 A0
struct MemList *AllocEntry(struct MemList *);
FUNCTION
This function takes a memList structure and allocates enough memory to hold the required memory as well as a MemList structure to keep track of it.
These MemList structures may be linked together in a task control block to keep track of the total memory usage of this task. (See the description of TC_MEMENTRY under RemTask).
These MemList structures may be linked together in a task control block to keep track of the total memory usage of this task. (See the description of TC_MEMENTRY under RemTask).
INPUTS
- memList
-
A MemList structure filled in with MemEntry structures.
RESULT
- memList
-
A different MemList filled in with the actual memory allocated in the me_Addr field, and their sizes in me_Length. If enough memory cannot be obtained, then the requirements of the allocation that failed is returned and bit 31 is set.
- WARNING:
-
The result is unusual! Bit 31 indicates failure.
The user wants five regions of 2, 4, 8, 16, and 32 bytes in size with requirements of MEMF_CLEAR, MEMF_PUBLIC, MEMF_CHIP!MEMF_CLEAR, MEMF_CLEAR, and MEMF_PUBLIC!MEMF_CLEAR respectively. The following code fragment would do that:
MemListDecl:
DS.B LN_SIZE * reserve space for list node DC.W 5 * number of entries DC.L MEMF_CLEAR * entry #0 DC.L 2 DC.L MEMF_PUBLIC * entry #1 DC.L 4 DC.L MEMF_CHIP!MEMF_CLEAR * entry #2 DC.L 8 DC.L MEMF_CLEAR * entry #3 DC.L 16 DC.L MEMF_PUBLIC!MEMF_CLEAR * entry #4 DC.L 32
start:
LEA.L MemListDecl(PC),A0 JSR _LVOAllocEntry(a6) BCLR.L #31,D0 BEQ.S success
------- Type of memory that we failed on is in D0
------- Type of memory that we failed on is in D0
WARNING
The result of any memory allocation MUST be checked, and a viable error handling path taken. ANY allocation may fail if memory has been filled.
Memory allocation and deallocation as well as querying how much memory is available requires a Task or, by extension, a Process. None of the exec kernel memory management operations is safe to call from interrupt code!
Memory allocation and deallocation as well as querying how much memory is available requires a Task or, by extension, a Process. None of the exec kernel memory management operations is safe to call from interrupt code!
BUGS
If any one of the allocations fails, this function fails to back out fully. This is fixed by the "SetPatch" program on V1.3 Workbench disks.
SEE ALSO
<exec/memory.h>