The adder at the heart of Intel's 8087 floating-point chip
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Re: The adder at the heart of Intel's 8087 floating-point chip
#2Author 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.
Re: The adder at the heart of Intel's 8087 floating-point chip
#3Author 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.
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.
Re: The adder at the heart of Intel's 8087 floating-point chip
#4[flagged]
Re: The adder at the heart of Intel's 8087 floating-point chip
#5Author 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.
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...
Re: The adder at the heart of Intel's 8087 floating-point chip
#6Do you have any insights on how power was delivered to these circuits? Maybe it's done in the metal layers that were dissolved? Also, is it correct that there is no on die capacitance surrounding these circuits?
Thanks for the great article.
Re: The adder at the heart of Intel's 8087 floating-point chip
#7Author 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.
> 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...
Re: The adder at the heart of Intel's 8087 floating-point chip
#8/* It's a bummer that there is addition but no vipition. */
Re: The adder at the heart of Intel's 8087 floating-point chip
#9/* It's a bummer that there is addition but no vipition. */
I knew a guy who bred snakes but could never really get much out of his adders.
Turns out what he needed to do was saw up some tree trunks to make rough platforms for them, and they bred like crazy.
Adders can multiply really efficiently with log tables.
Re: The adder at the heart of Intel's 8087 floating-point chip
#10It is interesting that over the years people have produced synthesizable RTL HDL for the 8086/8088 and later, with varying degrees of fidelity, but no-one seems to have produced similar for the 8087.