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The hell's a port command?
Posted: Thu Dec 06, 2018 2:17 pm
by CheeseBees
So, being the clueless boi I am, I consulted Wikipedia for the basics of a framebuffer. It says there are three common ways of doing it, and the attached image is the list.
I know the first and last ones but what is a port command?
Re: The hell's a port command?
Posted: Thu Dec 06, 2018 3:37 pm
by kzinti
It probably refers to the I/O port address space, which you can access with the OUT instruction on x86:
https://c9x.me/x86/html/file_module_x86_id_222.html
Re: The hell's a port command?
Posted: Fri Dec 07, 2018 1:43 am
by Octocontrabass
It refers to systems where the CPU can't directly address the frame buffer at all. Instead, you access it through one or more "ports" where you can write commands and data. For example, you might write a command to address a particular pixel, then write some data to set a new value for that pixel.
It has nothing to do with x86-specific things like the I/O address space or IN/OUT instructions.