ChanServ changed the topic of ##yamahasynths to: Channel dedicated to questions and discussion of Yamaha FM Synthesizer internals and corresponding REing. Discussion of synthesis methods similar to the Yamaha line of chips, Sound Blasters + clones, PCM chips like RF5C68, and CD theory of operation are also on-topic. Channel logs: https://freenode.irclog.whitequark.org/~h~yamahasynths
<andlabs>
of particular infamy is the "Andy Grove" one, which were made of unsold stock of versions of the Pentium chip with the FDIV bug
<ej5>
then of course you have the white ceramic 6502s that people are paying ridiculous sums for
<cr1901_modern>
I would say that keeping Yamaha chips alive today has more utility than keeping a Pentium w/ an FDIV bug alive today. I'm not really aware of any RE efforts for the Pentium. And even the simpler 486 is over 1 million transistors (thanks to the FPU).
<cr1901_modern>
68k is ~35,000 and that took Sarayan a year to RE?
<ej5>
68k is about 68,000 iirc
<cr1901_modern>
That was a marketing gimmick
<cr1901_modern>
A cute one, but marketing nonetheless
<ej5>
probably counts a transistor in every bit of the ROM array then?
<cr1901_modern>
Unless by "68000" they mean "that's the maximum that will fit in the allocated die space"
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<andlabs>
sure, but no one knew that when those gatchas were made
<andlabs>
also
<andlabs>
unrelated: can we have public domain netlists please
<andlabs>
(not like we own the rights to the transistor layouts, anyway; they're either facts (public domain) or the IP of the chip designers (Yamaha, Motorola, Intel, MOS))
<Lord_Nightmare>
we know what the cause of the fdiv bug is anyway, so in theory it can be LLE'd
<Lord_Nightmare>
its a bug in a division result lookup table in a radix-4 table
<cr1901_modern>
Why would you want to? FDIV bug is good for the jokes that came out of it and not much else
<Lord_Nightmare>
the last five values are supposed to be "+2" i think but are all 0 due to a truncated hex record file
<cr1901_modern>
"Why didn't Intel call the Pentium the 586? Because they added 486 and 100 on the first Pentium and got 585.999983605."
<andlabs>
the FDIV bug was fixed ages ago
<andlabs>
they were missing 5 entries in the lookup table Lord_Nightmare said and the fix was just to put them back
<Lord_Nightmare>
what i'd love to know is what all the entries in the fdiv table are, and also how to actually use said table to speed up division
<Lord_Nightmare>
something like multiplicative inverse and doing a multiply but more complex
* TD-Linux
singlehandedly destroyed the entire remaining stock of a YM chip