如何将两个位图的像素值一起异或？

I have some bitmap A which I modify to produce bitmap B. I want to efficiently produce a bitmap D by XORing the pixels values of A and B together such that D XOR A produces bitmap B and D XOR B produces bitmap A. I want to store the differences between the bitmaps so I can reverse changes that I've made.I have some bitmap A which I modify to produce