Scilab bitwise operations

Posted: MissRight Date of post: 16.06.2017

In Computer Engineering and in Systems with Microcontrollers areas of interest, performing bit operations is quite usual. In this tutorial we are going to learn what bit shifting and bit rotation means, an how to implement some simple algorithms in Scilab. Any decimal number can be represented in binary format and vice-versa. For an easy conversion from decimal to binary, we can use the Scilab functions dec2bin and bin2dec. For example, the decimal value 60 is represented in binary as The number 8 in the dec2bin function states how many bits we use to represent the binary notation.

How to Use Scilab: Logic Operations

Bit shifting and bit rotation means moving bits from one position to another. There are similarities between bit shifting and bit rotation, the former having the property of keeping all the values of the bits, not loosing any. Bit shifting means moving the position of the bits in the left direction or in the right direction. Bit 7 MSB was replaced by bit 6, bit 6 by bit 5 and so on. Since bit 0 was moved into position 1, a new bit 0 is stuffed in, with the value 0.

After shifting, with one position, we got a new binary number. If we convert it to decimal, we get:. Our initial decimal number was 23 , after shifting the bits left with one position we got 46 , which is twice the initial value. Let see what happens if we shift the bits left but with two positions.

Again, the final number 92 is twice the initial one We can now conclude that left bit shifting with n positions means multiplying the initial number with 2 n.

What about right bit shifting? As the name suggests, the bits are moved to the right. If we take the same example, decimal 23 in binary is Shifting to the right with one position will result in the binary number Converting to decimal representation gives Right bit shifting is the equivalent of dividing the decimal number with 2 n , where n is the number of positions to shift.

Scilab does not contain embedded functions for bit shifting. To overcome this limitation we are going to implement a custom Scilab function for bit shifting, defined as:. The Scilab functions uint8 , uint16 , uint32 and uint64 are used to format the decimal value on the corresponding number of bits as the function argument bit. Save the script file as bitshift. Now you can use it in the Scilab console.

Bitwise operations — scilab beta documentation

If we want to display the same result on 32 bits, we need to change the bit argument as:. If we want to work only with decimal numbers, we can also put the function bitshift as an argument for the bin2dec function. Bit rotation is similar to bit shift.

It actually is bit shift but with a difference. The end bits, MSB or LSB are not any more lost and they come back on the other side of the string.

Bit rotation is also known as circular bit shift. When performing left bit rotation , with one position, bit n is replaced by bit n-1 , and MSB comes at the back of the queue, replacing LSB. If we rotate left, one position, we get , or decimal This is because we rotate back the bits on the initial positions, and becomes Thus, we are going to implement a custom Scilab function to perform bit rotation.

As you can see, bit rotation also known as circular bit shift can be performed using left, right bit shifts and bit OR operations. The same principle applies to right bit rotation but with reversed bit shift operations. The syntax of the function is:. As you can see, the arguments of the bitrot function are defined in the same way as the arguments of the bitshift function.

For left and right bit shifting we are using the bitshift function defined above. LS and RS are local variables representing the Left Side and Right Side of the bit OR operation. To perform the bit OR operation we used the Scilab bitor function. Notice that this function expects decimal inputs and returns also decimal outputs. Save the file as bitrot. Now it can be called in the Scilab console.

scilab bitwise operations

If we want to use decimal numbers instead of binary representation strings, we can use the dec2bin function instead of the str argument:. We can return the result of the bit rotation into a decimal value, by using the bitrot function as argument for the bin2dec function:.

For example SHA Security Hash Algorithm contains several bit shift and rotate operations in its algorithm. WHY DO WE SHOW ADS: Ads are vital for the content on x-engineer.

We are also hosting our site on a very fast server, which requires high maintenance costs. We always use static ads, no pop-up windows, in order to minimize the impact on the browsing experience of the user.

Bit shift and bit rotation algorithms with Scilab implementation – uqyhadet.web.fc2.com

We try block unfair ads as much as possible. If you find really misleading or fraudulent ads, please take a screenshot, copy URL of a website where it points to and let us know using the Contact page.

Please disable your Ad Blocker on x-engineer.

Rating 4,5 stars - 335 reviews
inserted by FC2 system