bit manipulation - Check if bit has toggled in C -

i working on bitwise manipulation (in c) , wanted know how check if bit has toggled between previous value , new value.

example :     oldvalue = 0x0ff //0000 1111 1111 in binary     newvalue = 0x100 //0001 0000 0000 in binary

in example want check if bit8 (9th bit) has toggled 0 1.

i know if want know if bit set, can use :

value & (1 << 8)

so, correct ? :

if( (oldvalue & (1 << 8)) == (newvalue & (1 << 8)) ) //return 0 if toggled

you can in 2 steps:

first, use xor find all bits have toggled:

int alltoggled = oldvalue ^ newvalue;

then mask bit want keep - example, shifting alltoggled right, target bit @ position zero, , mask 1:

int targetbittoggled = (alltoggled >> 8) & 1;

now combine these 2 expressions single condition:

if ((oldvalue ^ newvalue) & (1 << 8)) {     // ... bit @ position 8 has toggled }

note instead of shifting xor-ed values right shifted bit mask left.

harsh