bitmasks are data used for bitwise operations.
Questions tagged [bit-masks]
54 questions
1
vote
3 answers
Analysing &, && and | for this code?
I want to illustrate the difference with this code
for(i = 32; i > 0; i--)
{
if(a&1 != 0) //bit mask
total += b;
a = a >> 1;
b = b << 1;
}
In the code & is used to "mask" a bit and the result would have been completely different…
Niklas Rosencrantz
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1
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2 answers
Writing a function: short GetBits(short data, int p, int n)
I am writing a function short getBits(short data, int p, int n)
I have tried:
public static short getBits(short data, int p, int n) {
short bitmask = (short) ((~0 << (16 -n)) >>> p);
short returnVal = (short) ((bitmask & data) >>> (16 -…
powerj1984
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0
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4 answers
How to check a returned bit mask value?
I am calling this function from C#:
GetKeyboardStatus()
Looking at the documentation it says that it returns a bit mask value. The goal of my code is to determine if the device has a physical keyboard with alphanumeric characters. I have…
still_dreaming_1
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0
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0 answers
Quantize normalized vector for network communication
I am wondering if is possible to send Vector3(float x, float y, float z) in some kind of shorter data type, because right now I am sending three floats (3*4 bytes). I am talking about normalized vector, which can hold only range from -1f to +1f for…
MrIncognito
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0
votes
1 answer
I need an infinite bit-mask in C++
Skippable Context: I have a simulation loop (using fixed update but variable rendering pattern), which instantiates entities of classes that are generated on the fly according to user-input and/or file configurations from a database of millions of…
Havoc Lamperouge
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0
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1 answer
Masks (macros of bits)
So I'm about to finish my course in university in C programming.
I want to get better at bit operations (such as creating masks) so I'll go to it:
#define BIT_I_SET(TYPE,I) ((TYPE)(1) << (I))
#define SET_BIT(NUM,I,TYPE) \
NUM |=…
AmitBL
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0
votes
2 answers
Finding a mask value with higher and lower position of the register
A 32 bit register i.e. status_reg has 1 field (field_1 <0:31>). To set and clear this register I am trying to get mask value of this register. So in general to get mask value the formula is:
mask = ((~(~0 << (hbit-lbit+1))) << lbit)
In this hbit is…
ziga
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0
votes
1 answer
Trouble with bit masks in SpriteKit SWIFT
In my game I have circles that have different colors. They should only collide with boundaries that are not of their color.
To do that I at first assign the normal circle a category bit mask.
struct CollisionCategoryBitmask {
static let…
Lenny1357
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0
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1 answer
Bit Masking in C#, converting from enum to byte []
I have a question regarding bit masking which I am completely new to.
In the application there is currently means of taking a byte[] of addresses and from them determining which alarms (bools) are true of false.
I am looking to reverse this. I would…
Colm Clarke
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0
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1 answer
st_mode of a symlink has weird value
I'm stat()'ing this symlink (on Kubuntu GNU/Linux 16.04), and am getting the weird value of 0100600 octal (33152 decimal). If I bitwise-and it with S_IFMT (which is 0170000 octal), I get 0600 octal. What does that mean? stat.h lists the following…
einpoklum
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0
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0 answers
How to represent in bistmasks the type of bounce of AWS SES
I'm writing a Symfony's Bundle to manage AWS SNS notifications sent by AWS SES.
I'm representing a Bounce object and for the moment I'm using constants:
/**
* A Bounce Entity.
*
* @see…
Aerendir
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0
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1 answer
ulong, bitmask and bit shift in PHP from C#
Ok so my problem is that I've to "process" a big integer from an endpoint response. This is a hash and I've to do some bit mask and bit shifts in order to view this data (it's a version: major, minor, build, etc) in a human readable way.
In C# I've…
fratili
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0
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0 answers
Bit masking with decimal offset: Faster algorithm?
I've a sum build of 0 up to 3 specific decimal numbers that can build 8 different sums:
100 --- 100 --- 100 --- 100 ---
200 200 --- --- 200 200 --- ---
+ 400 + 400 + 400…
Sebastian Barth
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0
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3 answers
Why does the BitConverter return Bytes and how can I get the bits then?
As input I get an int (well, actually a string I should convert to an int).
This int should be converted to bits.
For each bit position that has a 1, I should get the position.
In my database, I want all records that have an int value field that has…
Boris Callens
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0
votes
4 answers
Why does bit shifting a negative number doesn't work?
Here is my code:
long x1 = -123;
long y1 = -312;
long x2 = -111;
long y2 = -112;
long packed = x1 | y1 << 15 | x2 << 30 | y2 << 45;
Debug.log("x1:" + ((packed) & 0b111111111111111));
Debug.log("y1:" + ((packed >> 15) &…
Gintas_
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