Bimap operation and APIs

Bitmap operations:

Bitmap can be used as efficient data structure. Where each bit can be used as information.

Let’s say we have a large stock of items. We can use a long variable to represent status (used / unused) of all items. Each bit represents one item.

If bit is 0 -> item is free,

If bit is 1-> item is busy.

We can keep track count of used/unused item using variable.

We have bitwise operations, which can use to manipulate Bitmaps. Few bitwise operations are listed below:

void set_bit(int pos, volatile unsigned long * addr)

sets the bit at position pos ; counting begins at addr.

int test_bit(int pos , const volatile unsigned long * addr)

checks whether the specified bit is set.

void clear_bit(int pos, volatile unsigned long * addr)

Deletes the bit at position pos (counting begins at addr).

void change_bit(int pos, volatile unsigned long * addr)

Toggle the bit value at position pos (counting begins at addr); in other words, a set bit is unset and vice versa.