Memory

The HAL provides access to the memory-related features of the hardware (such as paging), and also some minimal memory management, mostly for the purpose of Init and initial UOS startup. Memory may consist of several segments of varying characteristics. For instance, most systems have some of their physical memory address range mapped to ROM (such as the BIOS on PCs), whereas other memory is read/write and available for general use. The HAL considers each contiguous segment of the memory address space that is of the same general type as a separate area, which is assigned a unique index.

The HAL passes information about memory back to UOS using the following structure:

type TMemory_Info = packed record

Memory_Type : word ;

Low : int64 ;

High : int64

end ;

This information is only provided on physical memory, and is described below:

Item	Description
Memory_Type	Type of memory. See Memory types, below.
Low	Lowest address of this segment
High	Highest address of this segment

Memory types have the following values:

Value	Mnuemonic	Description
0	MT_Non_Existant	Non-existant memory
1	MT_RAM	Random access read/write memory
2	MT_ROM	Read-only memory
3	MT_WOM	Write-only memory