Sorry, but you actually sounds like one those people who dosen't really know how FP work.
> I shudder to think how many e-commerce sites use `float` for financial transactions!
The float IEEE-754 represent up to 9 decimal digits (or 23 binary digits) with precision. The double, represent 17 decimal digits. The error upper bound is (0.00000000000000001)/2 per operation. Likely irrelevant for most e-commerce.
Also, the database stores in currency values using fixed point.
> Intel chips have had BCD support in machine code
BCD is floating point encoding not fixed point. AFAIK, only Intel supports it and very precariously.
> I'm surprised nobody has made a decent fixed point lib that is widely used already.
Nonsense. If you do any scientific computation you have likely have Boost, GMP, MPFR installed in your system. They support arbitrary precision arithmetic with integer (aka fixed point), rational and floating point.
> I shudder to think how many e-commerce sites use `float` for financial transactions!
The float IEEE-754 represent up to 9 decimal digits (or 23 binary digits) with precision. The double, represent 17 decimal digits. The error upper bound is (0.00000000000000001)/2 per operation. Likely irrelevant for most e-commerce.
Also, the database stores in currency values using fixed point.
> Intel chips have had BCD support in machine code
BCD is floating point encoding not fixed point. AFAIK, only Intel supports it and very precariously.
> I'm surprised nobody has made a decent fixed point lib that is widely used already.
Nonsense. If you do any scientific computation you have likely have Boost, GMP, MPFR installed in your system. They support arbitrary precision arithmetic with integer (aka fixed point), rational and floating point.