Art of Assembly - courtesy of Shawn Scout

• Art of Assembly - main page
• Art of Assembly - 16-bit DOS

Note that the PDF version is the most up-to-date and accurate version, but the web page for the hard-copy does not have the TOCs or the Index. Best to use the "PDF Online" option, where everything is available in one place.

Also, the 32-bit editions do not cover actual x86 assembly, but instead cover a creature made by the author, Randall Hyde, called "High-Level Assembly", or HLA for short. He seems to have basically added a swell of preprocessor macros to make the code far more legible (a handy trick). The DOS version has the best information on the innards of x86 I/O, from I/O ports up through DMA, including many memory addresses and interrupt numbers.

Interrupts - courtesy of Shawn Scout

• Interrupts

This guy has built a huge database of interrupt routines - hardware, software, you name it. We're not exactly sure of the last time he updated it, but the hardware stuff probably hasn't changed much anyway.

CAVEAT: A word of warning - of the links to the HTML versions of the interrupt list, Marc Perkel's site is far better for gaining access to the information, but Marc is your typical adult college male, and seems to be funding his site through some rather... explicit banner ads. Great database, if you have the stomach for that sort of thing; otherwise, stick with the other HTML version, or stick with the downloadable text version.