There are two (easy -- there are others) ways to pull it off. One is to replace instructions in the area with smaller ones, and take advantage of the open spac

There are two (easy -- there are others) ways to pull it off. One is to replace instructions in the area with smaller ones, and take advantage of the open space. This is generally fairly easy to do, as compilers are terrible at generating code that's both fast and small. The other way to pull it off easily is to replace an instruction with a jump to another part of code that's empty/unused, where you put the original instruction, your new ones, and a jump back to the patch location.