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.
来源：https://stackoverflow.com/questions/28862012/why-does-avx512-ifma-support-only-52-bit-ints