external assembly and protected mode

Unknown

Can anyone of you explain how I can use external

assembly functions in my watcom c (11.0)

How do the pointers work under protected mode?

How does interrupt calling differ from traditional?

Is there any other things I should know about this?

What registers does the external asm function have to push/pop?

Unknown

: Can anyone of you explain how I can use external

: assembly functions in my watcom c (11.0)

I don't use C, period, although I've heard lots of good things

about watcom c.

: How do the pointers work under protected mode?

Normally, you use flat 32-bit pointers, as you should be operating

solely within your program selector. However, the actual format is

48-bit, 16-bit selector:32-bit Index.

: How does interrupt calling differ from traditional?

You have to set up an IDT for each interrupt you plan to use. Extenders

will do this for you, for the most common ints.

: Is there any other things I should know about this?

Get a good book on protected mode. Everything is very complicated.

: What registers does the external asm function have to push/pop?

Just guessing here, but at least DS,SS,SP, and BP, I imagine.

It doesn't really have to "preserve" SP, but it does need to leave

it in a consistant state (i.e. pop what you push)


URL:http://acheronx.resnet.tamu.edu

Unknown

Could you explain a bit more about the use of

pointers under pmode?

Some interrupts ask for some address in form

seg:offs. How do I convert pmode pointer into

this form?