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# bitshift

Shift bits specified number of places

## Syntax

``intout = bitshift(A,k)``
``intout = bitshift(A,k,assumedtype)``

## Description

example

````intout = bitshift(A,k)` returns `A` shifted to the left by `k` bits, equivalent to multiplying by 2`k`. Negative values of `k` correspond to shifting bits right or dividing by 2`|k|` and rounding to the nearest integer towards negative infinity. Any overflow bits are truncated. If `A` is an array of signed integers, then `bitshift` returns the arithmetic shift results, preserving the signed bit when `k` is negative, and not preserving the signed bit when `k` is positive.If `k` is positive, MATLAB® shifts the bits to the left and inserts `k` 0-bits on the right.If `k` is negative and `A` is nonnegative, then MATLAB shifts the bits to the right and inserts `|``k``|` 0-bits on the left.If `k` is negative and `A` is negative, then MATLAB shifts the bits to the right and inserts `|``k``|` 1-bits on the left. ```

example

````intout = bitshift(A,k,assumedtype)` assumes `A` is of type `assumedtype`.```

## Examples

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Repeatedly shift the bits of an unsigned 8-bit value to the left until all the nonzero bits overflow.

```a = intmax('uint8'); s1 = 'Initial uint8 value %5d is %08s in binary\n'; s2 = 'Shifted uint8 value %5d is %08s in binary\n'; fprintf(s1,a,dec2bin(a))```
```Initial uint8 value 255 is 11111111 in binary ```
``` for i = 1:8 a = bitshift(a,1); fprintf(s2,a,dec2bin(a)) end```
```Shifted uint8 value 254 is 11111110 in binary Shifted uint8 value 252 is 11111100 in binary Shifted uint8 value 248 is 11111000 in binary Shifted uint8 value 240 is 11110000 in binary Shifted uint8 value 224 is 11100000 in binary Shifted uint8 value 192 is 11000000 in binary Shifted uint8 value 128 is 10000000 in binary Shifted uint8 value 0 is 00000000 in binary ```

Find the shift for a number using different assumed integer types.

`uintout = bitshift(6,5:7,'uint8')`
```uintout = 1×3 192 128 0 ```
`intout = bitshift(6,5:7,'int8')`
```intout = 1×3 -64 -128 0 ```

Use `bitor` and `bitshift` to pack four 8-bit bytes into the 32-bit integer they make up.

Create four bytes of data. Specify the data with hexadecimal literals, using the `-u32` suffix to specify that the data should be stored as `uint32`. Each byte contains 8 bits worth of data.

```byte4 = 0x87u32; byte3 = 0x65u32; byte2 = 0x43u32; byte1 = 0x21u32;```

Start by adding the first byte as the first 8 bits of a 32-bit unsigned integer.

`packedNum = byte1;`

Next, pack the other three bytes into `packedNum`, using `bitshift` to shift the bytes to the proper locations, and `bitor` to copy the bits over.

```packedNum = bitor(packedNum,bitshift(byte2,8)); packedNum = bitor(packedNum,bitshift(byte3,8*2)); packedNum = bitor(packedNum,bitshift(byte4,8*3));```

View the packed 32-bit integer.

```format hex packedNum```
```packedNum = uint32 87654321 ```

## Input Arguments

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Input values, specified as an array. `A` can be a scalar or an array of the same size as `k`.

• If `A` is a double array, and `assumedtype` is not specified, then MATLAB treats `A` as an unsigned 64-bit integer.

• If `assumedtype` is specified, then all elements in `A` must have integer values within the range of `assumedtype`.

Data Types: `double` | `int8` | `int16` | `int32` | `int64` | `uint8` | `uint16` | `uint32` | `uint64`

Number of switched bits, specified as an integer or integer array. `k` can be a scalar or an array of the same size as `A`.

Data Types: `double` | `int8` | `int16` | `int32` | `int64` | `uint8` | `uint16` | `uint32` | `uint64`

Assumed data type of `A`, specified as `'uint64'`, `'uint32'`, `'uint16'`, `'uint8'`, `'int64'`, `'int32'`, `'int16'`, or `'int8'`.

• If `A` is an integer type array, then `assumedtype` must specify that same integer type.

• If `A` is a double array, then `assumedtype` can specify any valid integer type.

Data Types: `char` | `string`

## Output Arguments

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Shifted values, returned as an array. `intout` is the same data type as `A`.

• If `A` and `k` are scalars, then `intout` is also a scalar.

• If either `A` or `k` is an array, then `intout` is the same size as that array.

## See Also

Introduced before R2006a

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