PM> Several people in this thread have mentioned that wide registers
PM> are needed for big number-crunching applications. True, but the
PM> registers in that case are the floating point registers, which in
PM> the 80x86 architecture are separate from the main processor
PM> registers. The floating point registers in these processors have
PM> always been 80 bits wide, and probably always will be.
AS> IIRC, the IEEE standard on floating point maths has something to
AS> say about the required precision and may therefore have a bearing
AS> on this.
I don't have a copy of IEEE 754 to hand, but people have stated that 80 bits
is simply the _minimum_ size for extended precision floating point, single
precision and double precision being more strictly defined.