On Fri, 7 Dec 2007, Roman Haefeli wrote:
On Fri, 2007-12-07 at 01:26 +0100, IOhannes m zmoelnig wrote:
i'll get my wishlist engine running before soon with stuff like:
- 64bit-pd (that is, not just run pd on an amd64; but have
t_float/t_sample be *large*)
does that mean, that every float in pd on an 64bit machine will have
64bit precision? and each sample in a table uses 8 byte ram? does it
also mean, that there will be less [tabread4~] floating point rounding
issues (in other words: [tabread4~] sounds 'good' up to x minutes?)
A day of mono 96000 Hz sound at 64 bits per sample would take 61.8 gigs of
RAM. This takes 33 bits of precision to address. This leaves 19 bits of
between-samples precision for interpolation by [tabread4]. The precision
of float64 is 52 bits, thus the number of significant bits is 53, still
not counting the sign. Thus float64 completely includes uint53 and int54.
This raises the counter problem's threshold to 9007199254740992.
And yes, it would use twice more RAM everywhere. This includes the cache,
so it may cause slowdown in some situations. I would enjoy it if [table]
and its friends supported int16 (mere CD quality) for example. I believe
that in float64 mode, pd could benefit from a float32 option on [table]
too.
_ _ __ ___ _____ ________ _____________ _____________________ ...
| Mathieu Bouchard - tél:+1.514.383.3801, Montréal QC Canada
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