Error: The class uint64 does not map to a 64-bit C type.

Question

Gerd Fuchs 2022-4-21

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1701715-error-the-class-uint64-does-not-map-to-a-64-bit-c-type

回答： Ayush Modi 2024-3-14

I've updated Matlab from 2017b to 2020b - because of my tool chain I'm restricted to certain releases and 2020b is the newest relase I can use at the moment. In my Simulink file I've implemented a Matlab function containing the bin2dec command. Everything worked fine in the 2017b release, but now, after the update, I get the error

"For code generation, integer input or result classes for TYPECAST must map directly to a C type in the target hardware. The class uint64 does not map to a 64-bit C type."

Why does this error occur and how can I resolve this issue?

I tried using the 'Bit to Integer Converter' Block from the Communications toolbox but this one doesn't work in my code because I get the value from an FPGA and in the communication interface I don't have the option to specify the number of bits. Hence, at the input, the value has the type 'double' and I have to convert it to a 12bit signed int.

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Answer 1

Andy Bartlett 2022-4-22

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1701715-error-the-class-uint64-does-not-map-to-a-64-bit-c-type#answer_948535

If this error is happening when you are explicitly attempting to generated code with MATLAB Coder, Simulink Coder, or Embedded Coder, then the following may solve the problem.

Make sure Hardware Implementation target provides 64 bit integer type.

Make sure your model's Hardware Implementation target provides a 64 bit integer type. Either

long is 64-bits

or

long long is 64 bits
Support long long is checked.

Some screenshots can be found here.

(10) How to Dramatically Increase Efficiency of Simulink Generated Code in Two Clicks! | LinkedIn

If this error is occuring due to implicit code generation such as simulating with a MATLAB function block or simulating with accelerator mode then I would not expect the previsous suggestion to solve the problem.