Initial commit - Begun rewrite of website generator

pages/2012-06-20-Kernel-Debug-Functions.md

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+layout: post
+title: "Kernel debug functions"
+subtitle: "Can't live without them"
+tags: [osdev]
+
+I read through the comments on my old OsDev series the other day and got stuck
+on one of them.
+
+> "\[...\] I noticed that you handle printing in the kernel, of all places. A kernel isn't supposed to do video output.\[...\]"
+
+I totally and whole-heartedly agree with this, and I really really wish I could
+code so well I didn't feel a need for outputting a single debug message before
+I had finished the booting procedure, physical and virtual memory management,
+interrupts, faults, thread and process handling, scheduling, system calls,
+message passing, virtual file system, a device driver framework, file writing
+library functions and a terminal driver. Alas, I am not that good, and
+therefore I find it helpful to print a message to the screen every now and
+then. Wheter the kernel's supposed to do video ouptut depends on the kind of
+kernel anyway.
+
+But enough with this immature passive aggressiveness. Let's do some kernel
+handled printing!
+
+Screen printing is usually quite simple. Most personal x86-based computers can
+do it by simply writing the text to a certain area in memory. I'm not going to
+waste very much time on it but pretty much just copy the code from an earlier
+project and move on to more interesting things.
+
+I also added some useful library functions and macros like min(a,b), max(a,b)
+and swap(a,b) and a few parts of the c standard library.  It can all be found
+in Git commit
+[16fdacb89](https://github.com/thomasloven/os5/tree/164fdacb896b3427633433f97bbd12d779a3d1f3).