Documentation

reinterpretcast

Convert fixed-point data types without changing underlying data

Syntax

c = reinterpretcast(a, T)

Description

c = reinterpretcast(a, T) converts the input a to the data type specified by numerictype object T without changing the underlying data. The result is returned in fi object c.

The input a must be a built-in integer or a fi object with a fixed-point data type. T must be a numerictype object with a fully specified fixed-point data type. The word length of inputs a and T must be the same.

The reinterpretcast function differs from the MATLAB® typecast and cast functions in that it only operates on fi objects and built-in integers, and it does not allow the word length of the input to change.

Examples

In the following example, a is a signed fi object with a word length of 8 bits and a fraction length of 7 bits. The reinterpretcast function converts a into an unsigned fi object c with a word length of 8 bits and a fraction length of 0 bits. The real-world values of a and c are different, but their binary representations are the same.

 a = fi([-1 pi/4], 1, 8, 7)
 T = numerictype(0, 8, 0);
 c = reinterpretcast(a, T)
a =
 
   -1.0000    0.7891

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 8
        FractionLength: 7
 
c =
 
   128   101

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Unsigned
            WordLength: 8
        FractionLength: 0

To verify that the underlying data has not changed, compare the binary representations of a and c:

binary_a = bin(a)
binary_c = bin(c)
binary_a =

10000000   01100101


binary_c =

10000000   01100101

See Also

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