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@ksaj @screwtape @amszmidt @riley
A little. The Accumulator register dates all the way back to the 4004; over time the 8008 then the 8080/8085 then the x86 registers became increasingly general purpose.
The A & D register meaning is retained somewhat more closely. Lisp was originally developed for the IBM 704, which had 15 bit "address fields" and 15 bit "decrement fields" in 36 bit words (plus 6 tag bits).
Something like that, anyway.
Extracting the "address field of register" and extracting the "decrement field of register" had pretty much the same meaning back then that CAR and CDR do today.
@dougmerritt Your timeline is so broken that I was hoping for a joke.
= 
log
) @dougmerritt@mathstodon.xyz@riley
Which part? The 4004 did have an accumulator. Lisp was originally designed for the 704.
https://en.wikipedia.org/wiki/Intel_4004
https://en.wikipedia.org/wiki/Lisp_(programming_language)
I don't need two people to simultaneously give me shit.
@dougmerritt 4004 is far, far newer than the IBM 704. The concept of accumulators predates computers entirely — they flow naturally from the original Hollerith process for automatic card-counting. (And even so, some early computer theorists were un-fond of them, so there were attempts to make machines with instruction sets that wouldn't imply a user-visible accumulator register.)
Before registers got names in their own, the single letters that eventually become some registers' names were single letters in the mnemonic codes of instructions, something on the order of lai for Load Accumulator Indirect.
@infosec.exchange @screwtape @amszmidt
@riley
That's all true -- NOR DID I SAY ANY DIFFERENT.
@riley
You assumed bad faith and that I was saying that the concept of an accumulator was invented for the 4004.
But I didn't say that.
The context was someone else bringing up accumulators in the x86 family.
That's a very very large reading comprehension failure.
@dougmerritt You described 4004 as "all the way back" and then swiftly moved on to 704. 4004 is not "all the way back" from 704.
@riley
I've got an idea. Fuck you. Blocked.