return wrong value

[yonggewang]

for the

function div256_128By256(uint a21, uint a0, uint b) public pure returns (uint q, uint r)

If we we b=2^128, a0=0, a21=2^128

then the output is: q= 2^129 . I think the output should be 2^128

[cag]

Yeah, output should be 2^128, this library is broken 😱

Edit: Also should note that I didn't actually confirm this, but for the time being I'm taking on good faith that this report is accurate right now.