Yes, I have a CL for parseInt. Just checking that there are no regressions. Will look into Number today CET.
-Anders On Tue, Feb 22, 2011 at 04:36, Ojan Vafai <[email protected]> wrote: > Is it not possible to apply similar optimizations for parseInt(..., 10)? I > don't think the conversion methods below are common knowledge and parseInt > is usually given the radix (e.g. Google's JS style guide requires it). If it > just optimized parseInt(x) and parseInt(x, 10), I think that would cover the > vast majority of uses. > > While we're on this subject, how does Number(x) compare? > > Ojan > > On Mon, Feb 21, 2011 at 9:20 PM, Florian Schneider < > [email protected]> wrote: > >> Math.floor should work fine - in general you can make use of the implicit >> conversions of Javascript operations: Two additional options that may be >> even faster come to my mind: bitwise-or and unary plus. Bitwise-or converts >> its input to integer-32, unary plus converts to a number. Depending on what >> the result should be, the most efficient ways with V8 to ensure that >> something is always a number (or an integer) would be: >> >> y = x | 0 // y is always int32 >> >> y = +x // y is always a number (floating point or int) >> >> or as already suggested by Mads: >> >> y = Math.floor(x) // y is always an integer (possibly larger than >> int32-range) >> >> --Florian >> >> Den 21. feb. 2011 00.57 skrev [email protected] < >> [email protected]>: >> >> I'm currently building a language for writing games that compiles >>> directly to JavaScript. As a part of this I wrap JS arrays inside my >>> own Array object, and inside it's 'set' method I run 'parseInt' on the >>> given key to ensure the index is always an int. >>> >>> Due to warnings given by the closure JavaScript optimizer I use, today >>> I changed 'parseInt( key )' to 'parseInt( key, 10 )' (the optimizer >>> gives you a warning if you fail to do this). However I found that >>> after adding the radix I received a major performance drop. I'm using >>> Chrome 11.0.672.2. >>> >>> With some of the array intensive examples (namely this one >>> http://playmycode.com/play/game/Sandbox/Blobs) the loss in framerate >>> was almost 60% (from around 35fps on my machine to 15fps)! That's >>> surprising since it's also doing lots of drawing too (although most >>> time is spent on the number crunching). Simply removing the redux from >>> parseInt solved this issue and brought the performance back up. >>> >>> In my own primitive benchmarks (running parseInt 1000's of times) I >>> find similar, but with less of a performance drop. I'm just really >>> stunned that simply supplying the radix can cause such a big drop in >>> performance. Could this be solved in the future? >>> >>> -- >>> v8-dev mailing list >>> [email protected] >>> http://groups.google.com/group/v8-dev >>> >> >> -- >> v8-dev mailing list >> [email protected] >> http://groups.google.com/group/v8-dev >> > > -- > v8-dev mailing list > [email protected] > http://groups.google.com/group/v8-dev > -- Anders Thorhauge Sandholm Product Manager Google Denmark ApS | CVR nr. 28 86 69 84 | Frederiksborggade 20B, 1 sal | 1360 Copenhagen K | Denmark -- v8-dev mailing list [email protected] http://groups.google.com/group/v8-dev
