Change the implementation of Math.random to use George...

Change the implementation of Math.random to use George
Marsaglia's multiply-with-carry instead of mixing the
bits obtained from calling the system random() twice.

This seems to be a bit faster and gives a better 
distribution than the system random() in particular on 
Windows. 

Committed: http://code.google.com/p/v8/source/detail?r=2159

[Kasper Lund, 2009-06-15 07:15:17]

Ready for initial review.

[Mads Ager (chromium), 2009-06-15 07:22:56]

LGTM

http://codereview.chromium.org/126113/diff/39/43
File src/v8.h (right):

http://codereview.chromium.org/126113/diff/39/43#newcode98
Line 98: static uint32_t Random();
Could these be in utils?

[Dean McNamee, 2009-06-15 07:39:25]

Hey Kasper,

This is great, I had talked to Ivan once about it before.  It's good that we
avoid system random for a few reasons, including thread safety / lock holding /
etc.


I know nothing of the implementation though, I would have gone with mersenne
twister since it is what everyone else uses (python, ruby, etc)

http://codereview.chromium.org/126113/diff/39/48
File src/v8.cc (right):

http://codereview.chromium.org/126113/diff/39/48#newcode145
Line 145: static uint32_t lo = 0;
why not just static uint32_t hi = random() ?