如何从确定的位置检查一组位是否为0？

I'm writting a bitmap physical memory manager and i want implement a function that checks if a n bits are free starting from an specific bit. Right now I use this function that checks if a single bit is free and i call it n times to see if n bits are free but i think it is not very efficient to do it this way:I'm writting a bitmap physical memory manager a