Puzzle

How retiring segmentation in AMD64 long mode broke VMware

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UNIX, Windows NT, and all the operating systems in their class rely on virtual memory, or paging, in order to provide every process on the system a complete address space of its own. An easier way to protect processes from each other is segmentation: The 4 GB address space of a 32 bit CPU is divided into segments (consisting of a physical base address and a limit), one for each process, and every process may only access their own segment. This is what the 286 did. read more

The C ! operator

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In C, the ! (“logical NOT”) operator used on a value x evaluates to 0 when x is not 0, and 1 when x is 0. In other words, it’s equivalent to the following C: read more

First assembly puzzle!

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This is our first assembly language puzzle for the new site! These puzzles are tests to see whether you are good enough of an assembly nerd, and to learn some tricks if you’re not =^_^= read more