All Questions
11 questions
6votes
3answers
1kviews
6votes
2answers
1kviews
Shifting an 128-bit integer consisting of four 32-bit integers
For a little project of mine I have written two versions for shifting a 128-bit unsigned integer consisting of four 32-bit unsigned integers in x86 assembly. I cannot really decide which is better in ...
- 161
7votes
5answers
270views
Assembler-program which reverses the content of EAX
Following exercise: Write a program that takes a number (of size 4 bytes) x as input, and then reverses all the bits of x, and outputs the result. By reversing all bits we mean that the ...
- 4,814
32votes
3answers
7kviews
Decide if the sum of three numbers is even or odd
Exercise from an Assembly course I'm enrolled into: Write a program that takes three numbers x,y,z as input, and returns: 0 if (x+y+z) is even. 1 if (x+y+z) is odd. (Note that here ...
- 4,814
1vote
1answer
2kviews
Decide if a number is even or odd by using bitwise operator
The following exercise is from an Assembler-course I'm taking: Write a program that takes a number x as input, and returns: 0 if x is even. 1 if x is odd. Full exercise-page here: ...
- 4,814
3votes
2answers
1kviews
Assembly: Sum up the single bytes of a 32bit-register to a checksum
Exercise description: "Write a program that takes a double word (4 bytes) as an argument, and then adds all the 4 bytes. It returns the sum as output. Note that all the bytes are considered to be of ...
- 4,814
6votes
6answers
20kviews
A simple assembly program to count the number of ones in a register
I made a simple assembly program to count the number of ones in a register. Since this is basically my first ever, I would like to hear what I can improve or if there are some major flaws in this one: ...
- 728
4votes
0answers
188views
Parallel popcount of packed bytes
I want to do a popcount of bytes in an array. Not a total popcount of everything, but lots of little popcounts for every individual byte to determine the neighborhood count in GoL. The following ...
- 417
2votes
1answer
181views
Routine to convert decimal digits to Densely Packed Decimal
I've written an amd64 assembly routine (in gas syntax using the System V calling convention) to convert three decimal digits to Densely packed decimal because I wasn't satisfied by the performance of ...
- 721
9votes
3answers
17kviews
Integer square root in x86 assembly (NASM)
This program calculates the square root of an unsigned 32-bit number with some bit fiddling to get a very close approximation, then one iteration of the Babylonian method to get an exact value. I don'...
119votes
11answers
53kviews
Fastest way to clamp an integer to the range 0-255
I'm working on some image processing code that can generate pixel values outside of the normal range of 0 to 255, and I'd like to clamp them back into the valid range. I know that there are saturating ...
- 1,876
