MATLAB: Floating point to 16 bit hexadecimal

floating point

Hello all, how can i convert floating point decimal to 16 bit hexadecimal value?

Thank you

Best Answer

You can use this file exchange submission. It will convert your number to 16-bit half precision format. But instead of returning as a string, it will return the equivalent uint16 MATLAB object. To get binary string, you can do this,

halfPrecisionNumber = halfprecision(1.2);  % halfprecision() is provided in the file exchange package.
halfPrecisionString = dec2bin(halfPrecisionNumber, 16);

In case you face the following error on running the package

"Floating point bit pattern is not IEEE 754"

you can try following

Open halfprecision.c file.
Add following to include section

#include <stdint.h>

Replace 4 #define with the following macros

#define INT16_TYPE int16_t 
#define UINT16_TYPE uint16_t 
#define INT32_TYPE int32_t 
#define UINT32_TYPE uint32_t

Run mex halfprecision.c.

Related Solutions

MATLAB: How to convert binary data into fixed point data

First, get the raw integer values in to MATLAB as either uint32 values or int32 values.

Second, use the reinterpretcast function

Example run this code

% Get the raw integers into a uint32 or int32
%   see MATLAB importdata and similar tools for ways
%   to accomplish this step
%


rawInteger = uint32(4275878552)
% Reinterpret data in the appropriate fixed-point type
%
vFixedPoint = reinterpretcast(rawInteger,numerictype(1,32,16))
% Compare hex values before and after
%   just to show the underlying stored integers are preserved
%
hexOrig = lower(dec2hex(rawInteger))
hexFixedPoint = vFixedPoint.hex
compareHexBeforeAfter = [hexOrig;hexFixedPoint]

see this output

rawInteger =
uint32
 4275878552
hexOrig =
  'fedcba98'
vFixedPoint = 
  -2.912711181640625e+02
        DataTypeMode: Fixed-point: binary point scaling
          Signedness: Signed
          WordLength: 32
      FractionLength: 16
hexFixedPoint =
  'fedcba98'
compareHexBeforeAfter  =
2×8 char array
  'fedcba98'
  'fedcba98'

For reference see the help

 >> help reinterpretcast
 reinterpretcast Convert fixed-point or integer data types without changing underlying data
    C = reinterpretcast(A, T) converts the input (integer or fi object) A
    to the data type specified by numerictype object T, without changing
    the underlying (stored integer) data. The result is returned in C.
    The data type of the input A must be fixed point or integer. 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 and integer types, and it
    does not allow the word length of the input to change.
    EXAMPLE:
      %%Convert from signed 8,7 to unsigned 8,0.
      a = fi([-1 pi/4], true, 8, 7)
      %   returns [-1.0000    0.7891] s8,7
      T = numerictype(false, 8, 0);
      b = reinterpretcast(a, T)
      %   returns [128   101] u8,0
      % Their binary representations are identical
      binary_rep = [bin(a);bin(b)]
      %    returns 10000000   01100101
      %            10000000   01100101

MATLAB: Does num2hex(1) return ‘3ff0000000000000’ in MATLAB

Hi Trevor,

Unlike dec2hex, num2hex converts to IEEE 754 hex notation (64 bits) See

https://babbage.cs.qc.cuny.edu/ieee-754.old/decimal.html

Best Answer

Related Solutions

MATLAB: How to convert binary data into fixed point data

MATLAB: Does num2hex(1) return ‘3ff0000000000000’ in MATLAB

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