Geek: what takes 80 seconds to do a double SHA-256 hash?

Geek: what takes 80 seconds to do a double SHA-256 hash?  An IBM 1401 mainframe computer, that's what.  The bad performance isn't just because of slow clock speed – it's also down to the fact that the 1401 doesn't have a conventional binary ALU; instead it uses BCD math.  The logical operations in the SHA-256 algorithm are relatively easy with a binary ALU; they are horribly difficult using BCD. 

Even on the old computers I first learned to program on, I never had that particular problem – they all had binary ALUs, though they didn't use two's-complement math (they used one's-complement math because back then it was slightly faster).  I did, however, once have almost the inverse of this challenge: I implemented a BCD-based floating point package (complete with logarithms and trig functions) that ran on an Intel 8080 microprocessor.  This was made slightly more bearable by the built-in support for adding two BCD digits packed into a byte – but still, multiplication and division were quite painful.  And painfully slow...