Nightloader/i386/docs/drivers/slot-structure.md

Nightloader Driver Structure

This documentation file explains the format of a native driver slot for the Nightloader on the i386 architecture.

Offset	Length	Name of Field
0	8	Driver Identifier
8	2	Format Version
10	2	Driver Version
12	2	Number of Functionalities
16	4	Functionality Table Offset

1. Driver Identifier
   The driver identifier is used to uniquely identify a driver. It can be chosen by a driver's developer, but should suggest what kind of driver is contained in that slot, for the sake of clarity.

2. Format Version
   The version of the driver slot's standardized structures such as the rest of the header, the functionality table and others that the future might bring.
   The first byte of this structure tells the major version, the second one tells the minor version. No version patches are needed.

3. Driver Version
   Version of the driver, as seen by the driver's developer.
   The first byte of this structure should be the major version, the second one the minor version. No version patches are needed.

4. Number of Functionalities
   How many entries the functionality table contains. The table of functionalities contains functions with standardized arguments, actions and return types for interfacing with the driver.

5. Functionality Table Offset
   Offset from the start of the driver slot to the functionality table. It may be wise to keep this a bit further away from the header to prevent the need for more changes if the header structure changes in a future version.

Functionality Structure

Functionalities in the functionality table have a structure defined in the following table:

Offset	Length	Name of Field
0	2	Function Category
2	2	Exact Function
4	4	Function Pointer

The functionality table as it is found in any correct driver is a tightly packed array of those structures with as many elements as were promised in the corresponding header field.

Driver Functionality Categories

The table below contains links to the driver functionality categories:

Id	Category
0x1	Basic Text
0x2	Text Window
0x3	Logger
0x4	Pixel Graphics
0x5	Pixel Fonts
0x10	PCI
0x11	PCIe
0x12	NVMe
0x20	USB
0x30	Storage
0x40	Filesystem