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by jedberg
2531 days ago
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It feels like programming used to be a much harder job in the past. You not only had to figure out the program logic, but you had to work within very tight hardware constraints. Reading articles like this, or about the Atari and how the code would double as a sprite in pac-man, or how 3D was rendered in Wolfenstein, makes me think one had to be much more clever back then. |
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The 6502 has a few "undocumented" instructions due the fact that if you have certain on/off input pin set, you're actually crossing gates used for multiple instructions. These may crash the chip or do non-useful things, but a few do something useful in vary specific circumstances. The trick to developing on these old systems is to experiment with the chips to understand what the system does in various circumstances.
What I liked about that time was that it was possible to truly understand everything about a system because nothing is hidden from you by software drivers. The were good times.