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How do u do message passing in assembly?

Posted: Sun Apr 20, 2003 12:15 am
by tom1000000
Hi,

I am making my microkernel and am wondering whats the best way to pass messages between processes.

For example, process A could easily use a system call to pass a message to process B.

Assuming that system calls pass the data through the registers (EAX - EDX), how do u physically get the message to process B? You can't write to process B's memory, obviously because process A is currently in memory.


How is message passing done at assembly level????

Re:How do u do message passing in assembly?

Posted: Sun Apr 20, 2003 5:46 am
by Pype.Clicker
it IS done by memory writes. Either because the microkernel has an own memory space that is visible in all process (but for the microkernel only), so that it could store "message for proces B : <eax><edx>" until it schedules process B, or because the microkernel temporarily maps a page of process B in process A and writes the message in it (and then unmaps the page :)

Re:How do u do message passing in assembly?

Posted: Sun Apr 20, 2003 9:49 pm
by tom1000000
Thanks for your ideas.