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So in a sense the 8087 was the first 64 bit CPU?

I wouldn't say so, because it was a co-processor: e.g., it depended on the 8086 to even generate addresses for memory operations.

I think the IBM 7030 Stretch CPU (from 1964) would be a likely contender for being one of the first 64-bit CPUs.

Also, even if ignored the fact that it was a co-processor, we don't generally count the width of the floating point and vector registers.

Otherwise most modern CPUs would be labeled as either 256-bit or 512-bit.

These days we generally label CPUs based on the width of the general purpose registers (though, it gets messy with things like the 68000). I personally suspect we won't ever see GPRs wider than 64 bits.

The Cray-1 (1976) was probably the first 64-bit CPU.

https://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_t... names Stretch from 01961 as the first natively 64-bit CPU, but maybe there are some that are even older?

I forgot about the IBM 7030 Stretch (1961), which was also 64 bits. The NORC (Naval Ordnance Research Calculator) (1954) had 16 decimal digits, which is sort of 64 bits.

Oh, that's a good point. I didn't know about the NORC.

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