The HAL

All hardware access is via the HAL (Hardware Abstraction Layer). Any hardware platform that has a HAL written for it can run UOS.

The HAL standardizes the way that various CPU hardware features are accessed. These features include:

I/O Ports

Memory

Interrupts

Ring (protection) levels

Hardware devices

Numeric coprocessing

The HAL maps the UOS requests into the platform-appropriate code.

The implementation of the HAL is beyond the scope of this manual. The standard interface is as follows:

type THAL = class

public

function Allocate_RAM( Size : int64 ) : pointer ;

function Boot_Device : TDevice_Info ;

function Console : TTerminal ;

procedure Deallocate_RAM( Value : pointer ; Size : int64 ) ;

function Device( Index : integer ) : TDevice_Info ;

function Disable( Device_Type, Controller, Device_Unit : word ) : word ;

function Enable( Device_Type, Controller, Device_Unit : word ) : word ;

procedure Device_Reset ;

procedure Halt ;

function Heap : PHAL_Heap ;

function Memory( Index : integer ) : TMemory_Info ;

function Radix : longint ;

function Store( Index : integer ) : TCOM_Store64 ;

procedure Set_Timestamp( Value : int64 ) ;

function Timestamp : int64 ;

function Use_Line_Clock : boolean ;

function Get_Line_Clock : int64 ;

procedure Set_Line_Clock( Value : int64 ) ;

function Valid_Time : boolean ;

function Set_Configuration( Address : pointer ; Size : cardinal ) : cardinal ;

end ;

Method	Description
Allocate_RAM	Allocates Size bytes of memory and returns a pointer to the first byte. Returns null if the memory couldn't be allocated.
Boot_Device	Returns information on the boot device. See TDevice_Info structure.
Console	Returns an instance of a TTerminal object used to access the system console. Returns null if there is no system console device.
Deallocate_RAM	Deallocates Size bytes of memory starting at Value.
Device	Returns information on the device at the passed Index.
Device_Reset	Resets all devices to initial state.
Disable	Disables the specified device.
Enable	Enables the specified device
Get_Line_Clock	Returns current line clock value.
Halt	Halts the system.
Heap	Returns a pointer to a HAL Heap instance.
Memory	Returns memory information for memory segment Index.
Radix	The base used for this hardware. For instance, Intel hardware would return 16 (hexadecimal).
Set_Configuration	Sets the startup configuration to the passed data.
Set_Line_Clock	Sets the line clock to Value.
Set_Timestamp	Sets the current clock to Value.
Store	Returns an instance of a TStore that corresponds to the device at index Index. Returns null if the index is invalid or the device is not a store.
Timestamp	Returns the current clock value.
Use_Line_Clock	Returns true if the system has a line clock.
Valid_Time	Returns true if the clock has a valid value.

Note that this is an abstract interface and all of the methods use stdcall calling standard.

Date/Time

Date and time stamps in UOS use the Sirius Timestamp standard which is the number of 100ns intervals since 12:00:00 am, Jan 1, year 0 (projecting the current calendar back).