Chi-Yi Lin wrote:
> In Palm OS Programmer's Companion, Chap 6 Memory, it says that heap
> header holds the size of the heap and contains flags for the heap. But it
> doesn't say what the flag format is. Does anyone know about the detailed
> format (the beginning 16 bits of the header) ? Or where can I get some
> more document about Palm OS?
>
> Following is the information I saw at the beginning of heap 0:
> 20 00 00 03 E8 00 00 00 06 EB 00 C8 00 00 ....
> ^^^^^ ^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^
> flag size master pointer table
>
> But I have no idea about the flag (2000) stands for...
The SDK files released with for OS 3.3 had a MemoryPrvNew.h file that included this:
typedef struct {
Word flags; // heap flags;
DWord size; // size of heap
DWord firstFreeChunkOffset;// offset/2 to first free chunk
MemMstrPtrTableType mstrPtrTbl; // Master pointer table
} MemHeapHeaderType;
typedef MemHeapHeaderType* MemHeapHeaderPtr;
// Flags Field
#define memHeapFlagReadOnly 0x0001 // heap is read-only (ROM based)
#define memHeapFlagVers2 0x8000 // version 2 heap (> 64K)
#define memHeapFlagVers3 0x4000 // version 3 heap (has free list)
Note the change. 'firstFreeChunkOffset' was added in OS 3.3.
This file is no longer a distributed header, but if I had to
guess, I'd guess that 0x2000 indicates that you have a
version 3.5 memory heap.
Is there any reason that files like MemoryPrv.h and DataPrv.h
are no longer distributed? There's some helpful information in
them.
-- Tim
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