Comment by RandomOnyx
5 days ago
Does rdrand32 and then taking the lowest 16 bits of its result yield any zeroes?
Basically I'm wondering if it's a bug in the version of the instruction that writes to a 16-bit reg, or a bug in the underlying RNG
5 days ago
Does rdrand32 and then taking the lowest 16 bits of its result yield any zeroes?
Basically I'm wondering if it's a bug in the version of the instruction that writes to a 16-bit reg, or a bug in the underlying RNG
Yes it does. rdrand32()%65535 was my first attempt, and generated zeroes at about the expected rate, that's why I initially erroneously thought my CPU did not have this problem.
You should be using &0xFFFF for masking. Your mod is off by 1 too.
You're right, the code was correct but my comment above is wrong.
How about* rdrand32()%65536? Taking the remainder by 65535 doesn't take the lowest 16 bits after all
*: missed a word the first time around