Thread: Why doesn't Jagex use Bitwise OR for their buffers?

Originally Posted by iKilem

In other words, it's platform dependant. A decent JVM implementation should apply optimisations if something like that is the case. For the developer, on the other hand, they're semantically equivalent here and nothing else (besides syntax differences obviously...)

There is absolutely no reason the bitwise or operator is slower than the addition operator unless the processor is specifically built for things like addition, which afaik no commercial ones are...

and afaik the jvm optimization does not go that deep into code to check if certain bit ranges are effected that it might be able to just use bitwise or.

it's not at all a syntax difference, it's a literal operation difference, the processor will be using a completely different circuit

and finally, the os does not effect those instructions, lol

Originally Posted by Thee End

the performance gain, if any, is negligible.

------------

they've used it for 10 years, so obviously back then it made a difference, and arguably still does today.

And with those functions you are talking about millions of calls to it, serious statement



Well anyway after all of these dull arguments, Flamable presented the best and most logical answer to the question, which makes a lot of sense to me

Originally Posted by Killer 99

There is absolutely no reason the bitwise or operator is slower than the addition operator unless the processor is specifically built for things like addition, which afaik no commercial ones are...

and afaik the jvm optimization does not go that deep into code to check if certain bit ranges are effected that it might be able to just use bitwise or.

it's not at all a syntax difference, it's a literal operation difference, the processor will be using a completely different circuit

and finally, the os does not effect those instructions, lol

I never said it was slower nor did I say the OS had any influence. I was referring to the CPU and the JVM when I said "platform".

>It's a literal operation difference
For the developer, not really. Even if the JVM doesn't do any optimisations, it's still negligible for something like this, like Thee End said.

Originally Posted by iKilem

I never said it was slower nor did I say the OS had any influence. I was referring to the CPU and the JVM when I said "platform".

>It's a literal operation difference
For the developer, not really. Even if the JVM doesn't do any optimisations, it's still negligible for something like this, like Thee End said.

Computing platform - Wikipedia, the free encyclopedia

x86 instruction listings - Wikipedia, the free encyclopedia

Code:

ADD

Code:

OR

Okay?

Originally Posted by Killer 99

Computing platform - Wikipedia, the free encyclopedia

x86 instruction listings - Wikipedia, the free encyclopedia

Code:

ADD

Code:

OR

Okay?

God damn you're a moron. Just because I say it's platform-dependant doesn't mean I consider the operating system to make a difference. The CPU and the JVM do, so it is platform-dependant. Why are you linking me to the x86 instruction set? Read my post carefully this time. Whether you use the addition operator or the bitwise OR operator in this case doesn't make a difference in terms of functionality. They are semantically equivalent. As far as the Java programmer is concerned, neither should impact performance more than the other. It's platform dependant. It's entirely down to preference. (I would personally use OR for consistency, but nonetheless...)

Originally Posted by fl3x

No it isn't. | is the correct choice. If you have two things that both always work, and one is most of the time faster, you'd have to be as stupid as you not to use it without alterior factors affecting your decision. I'd have to go with the guy that said it could affect their math obfuscation.

Don't get me wrong, I would use OR as well, but I wouldn't criticise someone for using addition either, for the reasons already stated. It's not most of the time faster. I don't think addition is used in the client due to the obfuscation, because it's been like that in the older clients which didn't mess with addition/subtraction.

Originally Posted by iKilem

Don't get me wrong, I would use OR as well, but I wouldn't criticise someone for using addition either, for the reasons already stated. It's not most of the time faster. I don't think addition is used in the client due to the obfuscation, because it's been like that in the older clients which didn't mess with addition/subtraction.

In RSC they used to multiply by 256 rather than using <<, so maybe they have room for improvement. If you want to use something that is slower, maybe not by much, but slower then go right ahead no one is stopping you. I'd like to note that java.nio.ByteBuffer uses OR. @"It's not most of the timer faster" It will always be faster it's just a matter of how much faster, no one has presented any benchmarks so buzz off and stop trying to defend it just because you don't like being wrong. Of course you are going to make a snotty response about me saying that, but do I really care? No, this was just a simple question I had and I didn't want some guy who probably doesn't even know how to use bit-wise operators tell me how a computer works

Originally Posted by Killer 99

In RSC they used to multiply by 256 rather than using <<, so maybe they have room for improvement. If you want to use something that is slower, maybe not by much, but slower then go right ahead no one is stopping you. I'd like to note that java.nio.ByteBuffer uses OR. @"It's not most of the timer faster" It will always be faster it's just a matter of how much faster, no one has presented any benchmarks so buzz off and stop trying to defend it just because you don't like being wrong. Of course you are going to make a snotty response about me saying that, but do I really care? No, this was just a simple question I had and I didn't want some guy who probably doesn't even know how to use bit-wise operators tell me how a computer works

I disagree with the statement "it's faster most of the time" because it depends on the platform. If in practice it does turn out to be the case, then it's correct in that sense, sure. Benchmarks aren't really relevant to what I'm saying. Whether java.nio.ByteBuffer uses OR depends on the implementation. See this: java.nio: ByteBufferHelper.java. It's used by some class ByteBufferImpl that extends ByteBuffer. It uses addition.