The subject of the post basically says my question - How do I get keyboard input without using interrupts? I would like if someone could give some code to do this, and please tell me how it works. While I'm asking that i would also like to know how to do the same thing with the mouse.
Thanks.
Hardware or Software Interrupts? You want to talk to the keyboard controller, not the BIOS?
in 16-bit code, you really can't handle the keyboard without some type of interrupt
in 32-bit code, you can't use interrupts at all (well - not easily) :P
so - my question is - why do you want to do this ?
is it because you are writing 32-bit code ?
if so, this is the wrong sub-forum :bg
I/O ports 60 and 64 are the data and status bytes. However, since key presses are asynchronous, interrupts work better.
-r
Hi,
You could poll the keyboard controller ports in a tight loop
and that would avoid using interrupts. Not a very goodi idea.
As Dave says you really should use either BIOS or DOS
interrupt routines. Or write your own interrupt handler. As
redskull hints, polling is not going to be the best way to get
keyboard data.
Regards,
Steve
Quote from: www.:).com on November 29, 2010, 09:01:34 PM
The subject of the post basically says my question - How do I get keyboard input without using interrupts? I would like if someone could give some code to do this, and please tell me how it works. While I'm asking that i would also like to know how to do the same thing with the mouse.
Thanks.
I wan't to know how to do this for protected mode programming, were i hear you can't use the interrupt to handle it, and would just like to know how.
Quote from: redskull on November 29, 2010, 10:57:55 PM
I/O ports 60 and 64 are the data and status bytes. However, since key presses are asynchronous, interrupts work better.
-r
Ive seen something online that did something with the number 64 that you posted. It was something like:
Keyboard:
in 64h
test -forget what was here-
-some kind of conditional jump-
;I sort of understand what is going on it just loops till a key is pressed, but why 64 as the I/O is it always this?
;If I were to put 60 in place of 64 what would i be accessing?
;Do you happen to know a tutorial for this or something that will tell me about it in detail?This code seems to have to do with what FORTRANS was saying:
Quote from: FORTRANS on November 29, 2010, 11:02:09 PM
Hi,
You could poll the keyboard controller ports in a tight loop
and that would avoid using interrupts. Not a very goodi idea.
As Dave says you really should use either BIOS or DOS
interrupt routines. Or write your own interrupt handler. As
redskull hints, polling is not going to be the best way to get
keyboard data.
Regards,
Steve
Quote from: dedndave on November 29, 2010, 10:34:04 PM
in 16-bit code, you really can't handle the keyboard without some type of interrupt
in 32-bit code, you can't use interrupts at all (well - not easily) :P
so - my question is - why do you want to do this ?
is it because you are writing 32-bit code ?
if so, this is the wrong sub-forum :bg
Why is it harder to use interrupts for this in 32-bit code than in 16-bit code?
in 32-bit code, interrupts are somewhat of a protected feature
the OS uses them, of course
and, if you write a driver, you might use them
i am still trying to figure out how to write a 32-bit driver - lol - not a simple thing
but, you can use the win32 API functions to access keyboard and mouse functions
in 16-bit code, interrupts provide the standard interface - very different from 32-bit
it would be hard to write anything but a trivial program that does not use interrupts in 16-bit
Quote from: www.:).com
Why is it harder to use interrupts for this in 32-bit code than in 16-bit code?
Because the BIOS sets up a workable 16-bit environment, but for 32-bit protected mode you have to do it yourself, or use a DOS extender to do the work.
i think you want to write a 32-bit program
the code you saw that used IN AL,64h was probably inside an interrupt handler or service routine
Quote from: www.:).com on November 30, 2010, 12:56:20 AM
Why is it harder to use interrupts for this in 32-bit code than in 16-bit code?
Because 32-bit programs run as user mode programs, within a 32-bit O/S, which restricts all access to peripherals. If any program could grab onto any of the system hardware at any time, then there would be no system stability. Programs which run under Windows have to use a modern-day equivilent of INT 21 for any system service, keyboard reading included. Executing a "DOS" program under Windows is simply a high quality (?) emulation of all that. If you are writing your own driver or O/S, then the rules change, but you are probably not (and certainly shouldn't) be doing that.
You don't write 32-bit programs; you write
Windows programs, and the difference is not trivial.
-r
ok, but how would i do this without interrupts even if it is not the best way to to it?
-mostly because i have never had luck with setting up an interrupt, I read that you have to store an address to the interrupt in the first 0 to 1024 bytes or something.
-If you happen to have some example code or tutorials for creating interrupts it would be useful to me as well.
gosh - i'd have to dig up some old code
i think you read the status port, then the data port
thing is - if you do this - you are asking the system to be hosed - lol
because, even if you are not using interrupts, BIOS still is
also - it may skip keys or something - the data from one key gets clobbered by the next
oh - and one data value means the key is pressed - another means it was released
(as i recall values below 80h are presses - they or 80h onto it to signify release)
you have to affect your own repeat
and - continually clear the buffer in the BIOS data area, unless you like beeping sounds
i still have to ask - why ????
you are taking the hard way, for sure
i almost forgot !
the data values are key numbers (and may vary slightly from one keyoard to another, too)
you will need a translation table to convert key numbers into characters and control codes
Quote from: www.:).com on November 30, 2010, 02:14:04 AMok, but how would i do this without interrupts even if it is not the best way to to it?
You have yet to clarify what system you are writing for, and whether it's software or hardware interrupts you are opposed to. To summarize:
1. If you are writing a 32-bit Windows program, you can't.
2. If you are writing a true 16-bit DOS program, you use the I/O port (reading port 60 will tell you the most recent keystroke)
3. If you are writing a 16-bit program to run in a DOS Box, then option two is not gaurenteed to work, but might.
4. If you are attempting to write your own 32-bit OS, then you should already know how to do it
-r
I'm not sure why you insist on plouging into areas you are not ready for, experience comes with time, and without a good foundation you're going to have a heck of a time making any progress.
Start by looking at the source code to a DOS Extender (like Causeway), add some of your own 32-bit code. Even without source code, something like DOS4G(W) would let you poke around with interrupts, and get some familiarity with them.
If you are not able to write a 16-bit interrupt routine, some DOS drivers, and a boot loader, then coding a 32-bit protected mode OS/Environment, and bit banging hardware probably isn't in your immediate future. Dig up some old books on PC hardware, and BIOS implementation. Dig up some old WinNT DDK sources.
There is a 16-bit DOS example of reading the data port directly here:
http://www.masm32.com/board/index.php?topic=13604.msg106677#msg106677
But note that the port is read in an interrupt handler, because doing it that way is much more efficient (and reliable) than polling for keystrokes. See multikey.asm in the attachment.
In a Windows app you can do something similar with GetKeyboardState (http://msdn.microsoft.com/en-us/library/ms646299(VS.85).aspx).
Thanks, and as for what redskull said:
Quote from: redskull on November 30, 2010, 02:30:24 AM
Quote from: www.:).com on November 30, 2010, 02:14:04 AMok, but how would i do this without interrupts even if it is not the best way to to it?
You have yet to clarify what system you are writing for, and whether it's software or hardware interrupts you are opposed to. To summarize:
1. If you are writing a 32-bit Windows program, you can't.
2. If you are writing a true 16-bit DOS program, you use the I/O port (reading port 60 will tell you the most recent keystroke)
3. If you are writing a 16-bit program to run in a DOS Box, then option two is not gaurenteed to work, but might.
4. If you are attempting to write your own 32-bit OS, then you should already know how to do it
-r
Im trying to do number 3 and i'm not so much opposed to interrupts it's just I never had luck with them - setting them up.
Hi,
Setting up the code to use interrupts is covered in many
old ASM books. DOS function 35H "Get Interrupt Vector"
returns the current address of the interrupt handler. DOS
function 25H "Set Interrupt Vector" allows you to use your
interrupt handler.
You could also use BIOS int 16H function 1 to return the
status of the keyboard and function 0 to retrieve the
character.
Steve
And I think that it is about time and required that you tell us what is the purpose of this program and why you want to do it in this strange ways.
Many DOS native things will not work in Win7 in a DOS box but some exploits are targeted on purpose for this hence please do explain your purpose / program.
There is no specific program in mind, I was just wondering how to do it without interrupts, for learning purposes.
Quote from: FORTRANS on November 30, 2010, 03:20:38 PM
Hi,
Setting up the code to use interrupts is covered in many
old ASM books. DOS function 35H "Get Interrupt Vector"
returns the current address of the interrupt handler. DOS
function 25H "Set Interrupt Vector" allows you to use your
interrupt handler.
You could also use BIOS int 16H function 1 to return the
status of the keyboard and function 0 to retrieve the
character.
Steve
-As for interrupt 25h does the new interrupt vector replace the old one or just extend it?
-Is the interrupt vector a variable location or is it always in a specific location independent of BIOS and DOS?
-Do you happen to know what possible values are stored in registers for int 16h function 1 & 0 and what they indicate? If not ill just search google.
You should consider devoting your time learning 32 bit code only.
You can keep your favorite 16 bit code and the .exes and .coms.
Andy
Answers to your questions :-
1 - You must save the interrupt vector before replacing it & restore it on program termination.
2 - The bottom 1k of memory stores the interrupt vectors, 256 of them.
3 - Function 1 of Int 16H returns with the zero flag set to 1 if there is a character in the keyboard buffer & 0 if not.
Number 3 above can be done 'manually' by checking the Head & Tail pointers in the keyboard buffer.
Quote from: www.:).com on November 30, 2010, 06:10:23 PM
There is no specific program in mind, I was just wondering how to do it without interrupts, for learning purposes.
This is the wrong way to do it.
Unless you write your own OS but even then you should use BIOS for 16 bits and then go to 32 bits and then eventually go to 64bits.
You do not seem to understand that there are 2 types of interupts:
a) Software interrupts that are in fact DOS or BIOS interfaces
b) Hardware interrupts or IRQ's that are in fact required by hardware.
"Learning" purposes is not good enough for going the wrong way. Please consider a better answer next time ;)
Locked.