Why does AVX512-IFMA support only 52-bit ints?

2019-06-27 04:25发布

问题:

From the value we can infer that it uses the same components as double-precision floating-point hardware. But double has 53 bits of mantissa, so why is AVX512-IFMA limited to 52 bits?

回答1:

IEEE-754 double precision actually only has 52 explicitly stored bits, the 53rd bit (the most significant bit) is an implicit 1.