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Inside Macintosh: Memory /

Chapter 3 - Virtual Memory Manager / Virtual Memory Manager Reference

Routines / Virtual Memory Debugger Support Routines

DebuggerLockMemory

To lock a portion of the address space (as the LockMemory function does) while leaving data caching enabled on the affected pages, use the DebuggerLockMemory function.

FUNCTION DebuggerLockMemory (address: UNIV Ptr; count: LongInt):
                              OSErr;

address

The start address of the range of memory that is to be locked in RAM.

count

The size in bytes of the range of memory that is to be locked in RAM.

DESCRIPTION

The DebuggerLockMemory function makes the portion of the address space beginning at address and having a size of count bytes immovable in physical memory and ineligible for paging. The function leaves data caching enabled on the affected pages.

If the address parameter supplied to the DebuggerLockMemory function is not on a page boundary, then it is rounded down to the nearest page boundary. Similarly, if the specified range does not end on a page boundary, the count parameter is rounded up so that the entire range of memory is locked.

ASSEMBLY-LANGUAGE INFORMATION

The trap macro and routine selector for the DebuggerLockMemory function are

Trap macro	Selector
_DebuggerLockMemory	$0006

The registers on entry and exit for this routine are

Registers on entry
D0	Selector code
A0	Starting address
A1	Number of bytes to hold

Registers on exit
D0	Result code

RESULT CODES

noErr	0	No error
paramErr	-50	Error in parameter list
notEnoughMemoryErr	-620	Insufficient physical memory