Lock Linear Region

Call With

AX = 0600H
BX:CX = starting linear address of memory to lock
SI:DI = size of region to lock (bytes)

Returns

if function successful
Carry flag = clear

if function unsuccessful
Carry flag = set
AX = error code

8013H	physical memory unavailable
8017H	lock count exceeded
8025H	invalid linear address (unallocated pages)

Notes

• If the function returns an error, none of the memory has been locked.

• If the specified region overlaps part of a page at the beginning or end of the region, the page(s) will be locked.

• This function may be called more than once for a given page; the DPMI host maintains a lock count for each page.

• This function is ignored by DPMI implementations that do not support virtual memory; the function will return the Carry flag clear to indicate success, but has no other effect. DPMI hosts which support virtual memory may also choose to ignore this function, but such hosts must be able to handle page faults transparently at arbitrary points during a client's execution, including within interrupt and exception handlers.