http://developer.intel.com/drg/mmx/manuals/prm/prm.htm: The official MMX technology programmer's reference manual can be found at Intel's developers web server.
http://www.web-sites.co.uk/nasm/: Written by Simon Tatham and Julian Hall, the Netwide Assembler (NASM) is a free portable assembler for the Intel x86 microprocessor series. It's definitely much easier to write assembly code using NASM than using GAS, the GNU assembler.
ftp://download.intel.com/design/PentiumII/applnots/24161812.PDF: To learn more about the information the CPUID instruction can confer, examine the document “Intel Processor Identification with the CPUID Instruction”.
http://www.dcs.ed.ac.uk/~mxr/gfx/2d/BMP.txt: The Microsoft Windows bitmap file format is fully described in this document.
All listings referred to in this article are available by anonymous download in the file ftp://ftp.ssc.com/pub/lj/listings/issue61/3244.tgz.