2-1. Manipulating Rightmost Bits
Some of the formulas in this section find application in later chapters.
Use the following formula to turn off the rightmost 1-bit in a word, producing 0 if none (e.g., 01011000 ⇒ 01010000):
This may be used to determine if an unsigned integer is a power of 2; apply the formula followed by a 0-test on the result.
Similarly, the following formula can be used to test if an unsigned integer is of the form 2n − 1 (including 0 or all 1’s):
Use the following formula to isolate the rightmost 1-bit, producing 0 if none ...