Changing Bits in Flag Words
Writing, reading or toggling bits in flags can be done only using the OR, AND and NOT operations - operations which can be performed quickly in the processor.
To set a bit, OR the status byte with a mask byte. Any bits set in the mask byte or the status byte will be set in the result.
int setBit(int val, int bit_position) { return val | (1 << bit_position); }To clear a bit, perform a NOT operation on the mask byte, then AND it with the status byte. The result will have the appropriate flag cleared (set to 0).
int clearBit(int val, int bit_position) { return val & ~(1 << bit_position); }To toggle a bit, XOR the status byte and the mask byte. This will set a bit if it is cleared or clear a bit if it is set.
int toggleBit(int val, int bit_position) { return val ^ (1 << bit_position); }Read more about this topic: Flag Word
Famous quotes containing the words changing, bits, flag and/or words:
“The aim of science is to apprehend this purely intelligible world as a thing in itself, an object which is what it is independently of all thinking, and thus antithetical to the sensible world.... The world of thought is the universal, the timeless and spaceless, the absolutely necessary, whereas the world of sense is the contingent, the changing and moving appearance which somehow indicates or symbolizes it.”
—R.G. (Robin George)
“Many bits of fox fur will make a fine robe.”
—Chinese proverb.
“By the rude bridge that arched the flood,
Their flag to April’s breeze unfurled,
Here once the embattled farmers stood
And fired the shot heard round the world.”
—Ralph Waldo Emerson (1803–1882)
“I wonder whether mankind could not get along without all these names, which keep increasing every day, and hour, and moment; till at the last the very air will be full of them; and even in a great plain, men will be breathing each other’s breath, owing to the vast multitude of words they use, that consume all the air, just as lamp-burners do gas.”
—Herman Melville (1819–1891)