Learning Challenge: ZX Spectrum machine code: Day 17

Day 17 started with me looking into the heart of the machine with the jump instructions JP and JR. JP takes a two-byte address and jumps directly to that address. JR is the equivalent, but instead of taking an address it takes a (signed ) byte to jump relative to the current address. So byte values from 80h-FF are considered negative jump values (FF = -1, FE=-2, etc) and bytes 00h-79h are considered positive values. The book then talked about comparisons which I'm going to need to re-read as it's an important topic and needs some further reading for me to fully understand it.

Fun stuff.


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