outportb

[PING]

guys, outportb in dos.h takes in the port id and the value to be written rite. what i want to ask is that how can i get the port ids of some standard devices like the sound output and for the visual display card and devices of that type. first of all,are the values standard for all computers, for these standard devices??

[SMurf]

You'd be in for a lot of work here. Yes, video cards are almost certainly located at the same ports on every PC, assuming you're dealing with a standard (VGA, VESA...). Unfortunately, accessing sound cards is a very different matter.

Modern soundcards reside on the PCI bus and are tricky to find, let alone identify. They don't tend to have a standard interface so you'd need to accomodate for many different models. Older soundcards were ISA and tended to follow Creative Labs's rule of hanging around port 220h, as well as being mostly 100% Soundblaster compatible, so they used the same interface.

The PC speaker, perhaps the only consistent sound interface across all PCs, is easier to use, although you'd have to know your stuff to get it to play wave files.

[Salem]

So what is your OS and Compiler PING?

[PING]

thanks for the reply SMurf. by the way,i dont use a sound card. i intend to take the output directly from sound output of the motherboard onto the speakers. And i use borland 3.0 turbo c++ and my OS is win98SE.

[RobR]

I don't know if this helps, but...

http://www.peltonweb.com/docs/asm_ports.htm

edit>> As you can see, they do tend to differ across different PC families.

[PING]

actually i am having trouble accessing the sound output of the motherboard. i am not sure how to test whether the sound blaster is located at a certain location or not. could anyone help ??

[Waldo2k2]

how exactly are you going to accomplish this ping...sound would be a product of software which makes a call to the OS which trys to interact with the sound card...which isn't there...so where are you pulling this sound from?


(unless you mean you have a ac97 codec chip on your mobo?)

[Waldo2k2]

so you're saying you have onboard ac97 sound?

[PING]

yes..it is ac97

[Waldo2k2]

ok, sorry about the double post, neither showed up originally for some reason. Who makes the chip? You may be able to contact them and see if that chip requests a certain irq...other than that it's going to vary from motherboard to motherboard and your program won't be portable. There's a reason for using higher level languages, this is one of them.

[PING]

i am not sure about the make of the chip. can u help me with how i can check whether the sound output is actually located at a certain port. i tried out some things and did some research in the past 3-4 days and i think i can be certain of the fact that it is between 220h and 230h. i am not sure about how i can test whether the output is located at a certain port. any help will be appreciated

[Waldo2k2]

well, the easiest way (since it is probably difficult to tell what data is actually sound) would be to write an app in C and assembly. Use assembly to store what you think might be sound data into a register (just try the ports sequentially), then use the return from your chunk of assembly in a win-api call for sound output (or whatever OS you're using). Maybe there's a way to put sound to the speakers in assembly but you'd probably have to know what port the sound card is listening on...which is what you're trying to figure out here so that wouldn't work.

[Salem]

Well it would help if you didn't keep tying your feet together with that old compiler, and started using something more appropriate for your operating system.

It's not like there's any shortage of good quality free compilers available.

[PING]

i have dev c++ and i use it sometimes. But i dont know how to use things like dos interrupts and stuff with it. Actually, i dont use that compiler all the time. only when i have to work with interrupts and things like that, i use the borland compiler, otherwise, i stick to dev c++.
by the way, i dont have a sound card Waldo,i am trying to take the output directly from the sound output on my Mobo. i tried using outportb to send different values to the ports between 220h and 230h, but there was no sound from the speakers. maybe that is not the correct way to check the port where it is located.

[Salem]

> But i dont know how to use things like dos interrupts and stuff with it.
That's because you CANT use DOS interrupts, and because you DONT need to either.

Everything you need to do is available somewhere in the win32 API - like for example if windows can play sounds through your ac97 sound system, then a program written in dev-c++ using appropriate win32 API calls will also be able to play sounds as well, without any need to go messing about with interrupts and ports.

What's more, your programs will have a much better chance of working on many other machines as well, rather than just people with machines identical to yours.