Bytes slower than integers - GameCreators Forum

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Jambo B

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Location: The Pit

Posted: 14th Aug 2011 14:51

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I wondered about using bytes to store smaller values rather than integers, so I tried a speed test first with a byte:

+ Code Snippet

sync on

global iMainLoopCount as integer
global dwStartTime as dword
global dwEndTime as dword
global byByte as byte

dwStartTime = hitimer()

repeat
	inc byByte
	if (byByte = 255)
		byByte = 0
		inc iMainLoopCount
	endif
until (iMainLoopCount = 500000)

dwEndTime = hitimer()

do
	set cursor 0,20
	print "RUNTIME = " + str$(dwEndTime-dwStartTime)
	nice wait 10
	sync
loop

...and then with an integer:

+ Code Snippet

sync on

global iMainLoopCount as integer
global dwStartTime as dword
global dwEndTime as dword
global iInt as integer

dwStartTime = hitimer()

repeat
	inc iInt
	if (iInt = 255)
		iInt = 0
		inc iMainLoopCount
	endif
until (iMainLoopCount = 500000)

dwEndTime = hitimer()

do
	set cursor 0,20
	print "RUNTIME = " + str$(dwEndTime-dwStartTime)
	nice wait 10
	sync
loop

(Uses Matrix plugins)

On my system, the byte code took an average of 4700 ms. to complete. The integer code took 4000 ms.

I'm a bit surprised about this! Why does that happen? Wondered if any of you technical-minded people knew.

James.

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Green Gandalf

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Playing: Malevolence:Sword of Ahkranox, Skyrim, Civ6.

Posted: 14th Aug 2011 15:01

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My guess is that bytes are implemented as integers so a lot of additional conversion work is going on when you use bytes.

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TheComet

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Location: I`m under ur bridge eating ur goatz.

Posted: 14th Aug 2011 15:19

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So are you saying it's better to just use integers rather than bytes?

TheComet

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Green Gandalf

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Playing: Malevolence:Sword of Ahkranox, Skyrim, Civ6.

Posted: 14th Aug 2011 15:54

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In DBPro possibly.

However, bytes can make coding simpler at times. For example, bytes automatically wrap round to 0 after 255:

+ Code Snippet

sync on : sync rate 20 : sync


b as byte
do
  cls
  inc b
  text 20, 20, str$(b)
  sync
loop

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Webber

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Posted: 15th Aug 2011 01:16

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That's interesting. I better stick with integers then.
For some unknown reason, Booleans are the same as bytes in DBPro.
I wonder if using Booleans instead of bytes would run faster then integers?

I like games, and stuff.

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Kevin Picone

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Location: Australia

Posted: 15th Aug 2011 01:41

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also, in the expression if (byByte = 255), DBpro is probably treating 255 as an integer and not a byte here. So the byte side of the expression is probably being recast to integer during the compare, making the comparison conceptually if (int(bybyte)=255)

Hmm, I wonder what's coming in 2011?

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Grog Grueslayer

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Playing: Green Hell

Posted: 15th Aug 2011 04:53

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I never use booleans because they take the same amount in a file as a byte (just 1 byte) and having a switch with 256 different possibilities is better than just a boolean switch with 0 or 1.

The way I see it we should all use the right data type for the job. If your variable is never going over 255 then use a byte. If it's never going over 65,535 then use a word and so on.

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Benjamin

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Posted: 15th Aug 2011 04:58

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It's much more efficient to use integers over bytes/words/dwords, in DBPro at least.

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Burning Feet Man

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Location: Sydney, Australia

Posted: 16th Aug 2011 06:58

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Grog Grueslayer, could you update that chart with Boolean as well?

Cheers,
BFM

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Grog Grueslayer

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Playing: Green Hell

Posted: 16th Aug 2011 09:40

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Actually it's not my chart... I copied it from the Darkbasic Pro help files but I've been thinking of making my own version.

Webber is right in Darkbasic booleans act like bytes with a limit of 0 to 255.

+ Code Snippet

` Make a boolean 
Test as boolean

do
 
 ` Increase Test
 inc Test

 ` Show Test
 print Test

loop

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Jambo B

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Posted: 16th Aug 2011 16:51

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After reading all the responses, I think I'm leaning towards using only integers in loops which need to be efficient.

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miso

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Posted: 17th Aug 2011 09:05

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I think its not dbpro specific. When you do calculations with your variables, your computer has to make conversions to 32 bit format, if your variables are different. Integers in dbpro are signed longs, so they need no further conversion in a 32 bit system, so theyre a bit quicker. It also works the same way in c++.

The speed increase is not truely big, so you have to choose what do you need more badly. A tiny speed increase or storage size. (signed longs are 4 times bigger in memory than a byte)

No place like 127.0.0.1 .

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DarkBASIC Professional Discussion / Bytes slower than integers