how to convert 2 double number and packed in 32 bit

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rps rathore 2015-8-21

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评论： rps rathore 2015-8-27

hi i want to convert 2 double number 0.5 and -0.5 in 16 bit and packed into 32 bit. each number in double takes 8 bytes. i want to convert in this number in fixed point 16,14 (2 bytes). and finally i want to packed these 2 number in 32 bit(4 bytes). please tell me how i can do this operation in matlab

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Walter Roberson 2015-8-21

Does 16,14 indicate 1 sign bit, then 1 bit of integer, then 14 bits of fraction? Or do you want to use 2s complement?

rps rathore 2015-8-24

yes my number is 16 bit in which 1 is sign bit , 1 bit integer part and 14 bit fractional part. my number range is +2 to -2. i am converting double number into fixed point number using sfi(Num,16,14); how to pack two 16 bits fixed point number in 32 bit .i packed this number beacuse i want to send this number by udp

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Answer 1

Walter Roberson 2015-8-21

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https://ww2.mathworks.cn/matlabcentral/answers/235066-how-to-convert-2-double-number-and-packed-in-32-bit#answer_189950

编辑：Walter Roberson 2015-8-21

typecast(int16(x*2^14),'uint32')

is one possibility depending on what you mean by 16,14

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Walter Roberson 2015-8-24

在 MATLAB Online 中打开

typecast(storedInteger([FirstFi, SecondFi]),'uint32')

or you might need

typecast([storedInteger(FirstFi), storedInteger(SecondFi)], 'uint32')

rps rathore 2015-8-27

thanks for replying . i have some problem in above equation. i am converting double number into fixed point using a=sfi(0.5,16,14) b=sfi(-0.5,16,14). i am converting fixed number into decimal and hex using hex(a) ans = 2000 dec(a) ans =08192, hex(b) ans =e000 dec(b) ans =57344. i am using your suggested equation for packing two fixed number into 32 bits c=typecast([storedInteger(a), storedInteger(b)], 'uint32')

c = 3758104576. This answer i am not able to interpret in decimal or hex.| if i am using hex function.it gave error hex(c) Undefined function 'hex' for input arguments of type 'uint32'. if i am using num2hex function.it gave error num2hex(c) Error using num2hex (line 32) Inputs must be floating point, and may not be of class uint32.

if i packed 2 number in 32 bit answer is in hex 2000e000, or in decimal 536928256. but i am not getting how i get this number 3758104576 using c=typecast([storedInteger(a),storedInteger(b)], 'uint32'). please help me how to interpret this number and explain how it is work

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