OCR: Wed 0 dacimal Beginners Guide Macintosh Assembly Language Programming 3Bage The Exclusive OR instruction works like: "If one bit is a 1 and one bit is 0 then the result is 1, otherwise the result is 0 Example EOR with 0001 1111 EOR 1110 decimal 14 EOR with 0 1000 0000 EOR 0001 so the result is 1. we EOR the result with 1we get a0 This is a neat of toggling a bit, every time a loop executes Initially the bit is set to 1. Each time round the loop, the bit is EOR'd with 1 Every time the loop executes. if the bit is a its set to a0 and l if its a O its set to a The instruction EOR #1,my _bit will toggle bit zero of my bit every time executes. What's the use of this? Suppose you want to flash I something, say an alien spaceship on the screen between red and vel llow You test my bit, if its a on ...
