alt Hacker NewsAuthor here for your 8087 questions. I find adders and ALUs interesting because they are key to the performance of a system and every system implements them differently.
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Any idea how much adder designs changed on modern CPUs compared to back then? I mean there's only so much you can optimize in those, I think...
No immediate questions, but happy to have some great weekend reading. A quick pass through finds one of the best and clearest explainers I've seen. Thanks for this and all the materials you produce.
> take two clock cycles to complete an addition.
How does the clocking work exactly? The circuit is fed A and B and up down up down clock and then the output appears? How does the consumer (circuit) know when to read the result? Is there a "result is ready" flag? How long does the result stay stable? One full clock cycle? So many questions...
Do you know about how many transistors are needed to implement the adder (or the FPU as a whole)? And how it scales with the width of the numbers (16 bit, 32 bit, etc)?
I've been curious about transistor counts for floating point units for a while, but it's hard to find information about them.