Get Free Memory Information

Call With

AX = 0500H
ES:(E)DI = selector:offset of 48-byte buffer

Returns

Carry flag = clear (this function always succeeds)
and the buffer is filled in with the following information:

Offset	Length	Contents
00H	4	Largest available free block in bytes
04H	4	Maximum unlocked page allocation in pages
08H	4	Maximum locked page allocation in pages
0CH	4	Linear address space size in pages
10H	4	Total number of unlocked pages
14H	4	Total number of free pages
18H	4	Total number of physical pages
1CH	4	Free linear address space in pages
20H	4	Size of paging file/partition in pages
24H	0CH	Reserved, all bytes set to 0FFH

Notes

• 32-bit programs must use ES:EDI to point to the buffer. 16-bit programs should use ES:DI.

• Only the first field of the returned structure is guaranteed to contain a valid value. Any fields that are not supported by the DPMI host will be set by the host to -1 (0FFFFFFFFH) to indicate that the information is not available.

• The field at buffer offset 00H specifies the largest block of contiguous linear memory in bytes that could be allocated if the memory were to be allocated and left unlocked.

• The field at buffer offset 04H specifies the largest number of pages that could be allocated (the value at offset 00H divided by the page size).

• The field at buffer offset 08H specifies the largest block of memory in pages that could be allocated and then locked.

• The field at buffer offset 0CH specifies the size of the total linear address space in pages. This value includes all linear address space that has already been allocated.

• The field at buffer offset 10H specifies the total number of pages that are currently unlocked and could be paged out. This value also contains any free pages.

• The field at buffer offset 14H specifies the number of physical pages that currently are not in use.

• The field at offset 18H specifies the total number of physical pages that the DPMI host manages. This value includes all free, locked, and unlocked physical pages.

• The field at offset 20H specifies the size of the DPMI host's paging partition or file in pages.

• The size of the pages used by the DPMI host can be obtained with the Get Page Size function (Int 31H Function 0604H).

• DPMI 1.0 clients should use Int 31H Function 050BH in preference to this function. This function is supported in DPMI 1.0 solely for backward compatibility with DPMI 0.9.