March 2010
Beginner
760 pages
18h 51m
English
As the example in the previous section indicates—indeed, as several examples up to this point have indicated—adding or subtracting 1 from a register or memory location is a very common operation. In fact, these operations are so common that Intel's engineers included a pair of instructions to perform these specific operations: the inc (increment) and dec (decrement) instructions.
The inc and dec instructions use the following syntax:
inc(mem/reg); dec(mem/reg);
The single operand can be any legal 8-bit, 16-bit, or 32-bit register or memory operand. The inc instruction will add 1 to the specified operand, and the dec instruction will subtract 1 from the specified operand.
These two instructions are slightly shorter ...