3 ms·

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

• matja 22d ago
  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.
  • phire 21d ago
    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.
• kens 22d ago
  The Cray-1 (1976) was probably the first 64-bit CPU.
  • kragen 22d ago
    https://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_timeline 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 22d ago
      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.
      • kragen 21d ago
        Oh, that's a good point. I didn't know about the NORC.