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Re: Any way to work with bits?
Posted: Thu Feb 25, 2010 1:33 pm
by infratec
You were right.
When I use
Code: Select all
MessageRequester("Time", Str(ElapsedMilliseconds() - StartTime))
and disable the debugger,
I got:
Long: 1531
Byte: 1750
But...
I had to increase the loop counter to 100000000.
Ok, it is faster. (2us)
But it needs 3 bytes more memory in the worst case
Bernd
Re: Any way to work with bits?
Posted: Thu Feb 25, 2010 1:37 pm
by Kaeru Gaman
well... s**t on three bytes.
in the end the allocation the OS makes for the process will happen in 512byte chunks or something like that, so it's less than unimportant.
Re: Any way to work with bits?
Posted: Thu Feb 25, 2010 3:42 pm
by infratec
Hi,
here is my final version:
Code: Select all
#MaxBits = 1024
Macro BitArraySize(Bits)
((Bits - 1) / 32 + 1)
EndMacro
Structure Test
arry.l [BitArraySize(#MaxBits)]
EndStructure
Define myTest.Test
Dim NormalArray.l(BitArraySize(#MaxBits))
Debug "Arraysize: " + Str(ArraySize(NormalArray()))
Procedure InitBits(*A.l, Bits.i, Value.l)
If Value <> 0 : Value = $FFFFFFFF : EndIf
FillMemory(*A, BitArraySize(Bits) * 4, Value, #PB_Long) ; * 4 because we need the bytesize
EndProcedure
Procedure SetBit(*A.l, Index.i)
*A + (Index >> 5)
PokeL(*A, PeekL(*A) | (1 << (Index & $1F)))
EndProcedure
Procedure ClrBit(*A.l, Index.i)
*A + (Index >> 5)
PokeL(*A, PeekL(*A) &~ (1 << (Index & $1F)))
EndProcedure
Procedure TglBit(*A.l, Index.i)
*A + (Index >> 5)
PokeL(*A, PeekL(*A) ! (1 << (Index & $1F)))
EndProcedure
Procedure.i GetBit(*A.l, Index.l)
*A + (Index >> 5)
ProcedureReturn (PeekL(*A) & (1 << (Index & $1F))) >> (Index & $1F)
EndProcedure
InitBits(@myTest\arry, #MaxBits, #True)
SetBit(@myTest\arry, 4)
Debug GetBit(@myTest\arry, 4)
ClrBit(@myTest\arry, 4)
Debug GetBit(@myTest\arry, 4)
TglBit(@myTest\arry, 4)
Debug GetBit(@myTest\arry, 4)
InitBits(@NormalArray(), #MaxBits, #False)
SetBit(@NormalArray(), 144)
Debug GetBit(@NormalArray(), 144)
ClrBit(@NormalArray(), 144)
Debug GetBit(@NormalArray(), 144)
TglBit(@NormalArray(), 144)
Debug GetBit(@NormalArray(), 144)
Now it uses long for the speed.
And I had a fault with the parameter of the NormalArray:
The address of the first element is
@NormalArray() and not @NormalArray
Bernd
Re: Any way to work with bits?
Posted: Fri Feb 26, 2010 3:07 pm
by Seymour Clufley
Thanks for this.
Re: Any way to work with bits?
Posted: Sun Feb 28, 2010 2:40 am
by idle
If you want it quicker better to use macros, I just ripped this from my bloomfilter
Code: Select all
*mem = AllocateMemory(32767/8)
Macro setBit(mem,bit)
*tb.byte
*tb = mem+(bit>>3)
*tb\b | (1 << (bit % 8))
EndMacro
Macro GetBit(mem,bit,x)
*tb.byte
mf = (bit % 8)
*tb = mem+(bit>>3)
x = (*tb\b & (1 << mf)) >> mf
EndMacro
getbit(*mem,1000,x)
Debug x ;"0"
setbit(*mem,1000)
getbit(*mem,1000,x)
Debug x ;"1"