High Level language not suitable for writing hardware device driver???

[pirigyi]

I'm new to programming and I was wondering if...

someone can please provide a few reasons why a High Level language is not suitable for writing a hardware device driver.

1. I understand it makes too much executable code causing it to run slow.

2. It's difficult to access hardware.

Anything else...

Thanks a million!

 

[jkapcia]

There are some machine instructions which may be essential to the proper operation of a driver that a high-level language may not be capable of generating. Jay

 

[AmkG]

3. Drivers have a special format which HLL's can't generate. (very important)

4. HLL's can't do inport and outport operations without calling separate functions.

5. HLL's use DOS a lot. However, when it is called, the driver IS DOS! It can't call itself!

NOTE: While HLL's can't be used as the BASIS for a driver, they (mostly C) CAN be used as SUPPORT for the driver (e.g. to output the driver's name on-screen using BIOS functions). Also, in theory you can make a "driver stub" in Assembly and use an HLL to fill the important parts - although you certainly will contend with low speeds and high mem usage.

 

[pirigyi]

Great Detail! Thanks for the help!

 

[cboxgo]

AmkG, can you not do inport/output operations with inline assembly?

 

[AmkG]

There's still consideration 3 to consider even if you can avoid considerations 4 and 5. I mentioned #3 is VERY important, at least in DOS. In theory, incidentally, you can make an asm header which handles the special header format, and link in your own HLL driver to that asm header. It may have been done already, in fact.

And if you're gonna dabble in ASM anyway, why not go ALL the way? "Information has a tendency to be free. Which means someone will always tell you something you don't want to know."