Member Avatar for therstonsplace

i have been trying to do any interrupts in protected mode and i have been using msdos interrupts so it makes sense that they are not working i have been working through the threads so as not duplicate this but i haven't found any and i figured i would just ask

im kind of new to assembly but im doing alright so far

openfile hasn't worked and just calling int 21h or int 14h hasn't worked


in fact if i just call sti to prepare the assembler for interrupts i get a problem not to mention trying actuall interrupts

i need to open a serial port in assembly using protected mode....

as well as set the baud rate

any ideas

thanks ahead of time and whatever i need to read i will...

thom

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Member Avatar for wildgoose

LEAVE STI ALONE!!!!!!!!!!!!!!

Interrupts are already turned on! If they weren't no input would be handled. No keyboard, no anything as they are all interrupt driven!

There is a Serial BIOS in DOS. If you're using a simulator you're dependent upon what interrupts they actually implemented! Typicall DOS, keyboard, and a few others!

You should be able to use the single character read and write but an actual handler will process the various UART registers such as transmit Buffer Empty, etc. Interrupts are Real Mode. I remember something from the old days in replicating code functionality in the Real Mode and Protected Mode layers to make sure that servicing still occured whether you were in Real Mode or Protected mode at the time.

I'm a little rusty with the interrupts on an 80x86 as Win32 (since the post Win98 days) blocks you from all access to ports, etc. I remember something like when an interrupt occurs, interrupts are disabled while its being serviced. One of the first thing an interrupt routine does is typically reenable interrupts while its servicing the interrupt, so as to allow other interrupts to occur.

Member Avatar for therstonsplace

its kind of exciting to get a response im new here...


and thank you i have been all over the web and have some source code ill be looking at either tonight or tomorrow and my book actually said the answer to this question is not in the book... i thought that was funny

but i like assembly (alot) as verbose as it can be

and we are trying to work a robot in assembly (god im a nerd!)

Member Avatar for wildgoose

Vex or First cmpetitions?

Or homebrew?

Member Avatar for therstonsplace

i was going over some source code a friend gave me....


and from it i confirmed what i thought (or rather i think i did)


i have to invoke createfile.... which does a number of things 1 of which is create a file for serial ports... but i went to use it and it didnt work

i need to know the whys to know what to do... i know i need all these arguments that go with the call delimited by commas and i think that it returns a handle for which to use later... but im not so sure about any of this


any more direction would be appreciated...

thanx

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