double vs real

[Timon Gehr]

On 05/30/2013 06:45 PM, bearophile wrote:
> ...
> If you have to store many reals, they require more memory than doubles
> (how much is relative to the operating system). Regarding speed in
> theory double and real should give the same, ...

If double uses xmm registers and real uses the fpu registers (as is 
standard on x64), then double multiplication has twice the throughput of 
real multiplication on recent intel microarchitectures.