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.

kens 5 hours ago | parent | prev [-]

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?

	▲	kens 5 hours ago \| parent [-]
		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.