Art of Assembly Language, 1st Edition

9.2. 9.2 Multiprecision Operations

One big advantage of assembly language over high level languages is that assembly language does not limit the size of integer operations. For example, the standard C programming language defines three different integer sizes: short int, int, and long int.^[136] On the PC, these are often 16- and 32-bit integers. Although the 80×86 machine instructions limit you to processing 8-, 16-, or 32-bit integers with a single instruction, you can always use more than one instruction to process integers of any size you desire. If you want to add 256-bit integer values together, no problem; it's relatively easy to accomplish this in assembly language. The following sections describe how extended various arithmetic and logical ...