by Derick Swanepoel, 2002. Programming in assembly may seem quite masochistic ( and writing entire programs in it simply ridiculous ), especially in these days of super-optimizing compilers and visual development tools that do just about everything for you. However, there is an advantage in understanding more about the inner workings of your processor and kernel, and assembly is a good way of learning this. Sometimes assembly can be extremely useful for sticking inline in a C/C++ program. And if your program really has a "need for speed", you can tweak and optimize the assembly generated by the compiler (of course, you need to be pretty elite to produce better code than today's compilers ). Linux will almost always be intalled with the default assemblers "as" and "as86" available, and quite likely also "gas". However, we will be using NASM, the Netwide Assembler. It uses the Intel syntax just like TASM, MASM, and other DOS assemblers, and the structure is also fairly similar. Useless info: as and gas use the AT&T syntax, which is somewhat different – eg. all registers must be prefixed with a %, and the source operand comes before the destination. NASM is cool because it's portable ( there are Linux, Unix and DOS versions ), it's free and it's powerful with lots of nice features.

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