[R] how much performance penalty does this incur, scalar as a vector of one element?

[Jeffrey J. Hallman]

The 64 bit version of VisualWorks Smalltalk has an immediate ShortDouble,
which sacrifices two bits of exponent for a tag.  It thus has the same
precision as an IEEE double, but one fourth as much range.  Overflows
automatically get promoted to ordinary Double's, which are pointers to objects
holding real IEEE doubles.

Luke Tierney <luke at stat.uiowa.edu> writes:
> Systems that
> support integer scalars often represent them as immediate values within
> pointers by sacrificing one or two bits of precision in the integers,
> but that doesn't work for double precision floats except possibly on
> 64-bit systems. 

-- 
Jeff