Articles by John Linville

In the previous post, I explained the difference of intent between “logical” and “arithmetic” shift operations in assembly language. I also demonstrated that for two’s complement binary numbers, the bitwise effects of logical-shift-left and arithmetic-shift-left are actually identical. This makes the choice to implement a single physical instruction that covers …

Recently I was listening to a retrocomputing-themed podcast, as I am often wont to do… This particular podcast has a recurring segment wherein a game developer from the good old days is presenting some relatively simple lessons on programming in assembly language for the Motorola 6809. This particular lesson was …