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Now that Casey has given his lecture on "The Thirty-Million Line Problem" again, I'd like to talk about some of the things that came up from an operating system perspective.

x86-64 vs x86

Having written code that bare-metal boots 20 years ago and a few years ago, these are the main differences between booting on the two:

  • Going from 32-bit mode to 64-bit mode is about 10-20 lines of assembly. However, that's not the hard part. The hard part is that there is no such thing as 64-bit "real mode", so you also need to set up page ...
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