How can I avoid doubles from char arithmetic in fixed-point codegen in MATLAB Coder R2025a?
显示 更早的评论
I am generating fixed-point code using Fixed-Point Designer and MATLAB Coder R2025a. My code will be used on a small embedded microcontroller that does not support floating-point operations. One of the lines of code that is being translated as resulting in data of type
"double" rather than "char" is the following:
x(:) = (s(i) - '0');
where "s" is a character array.
What do I need to do to get the generated code to not use doubles in instances like this?
采纳的回答
MathWorks Support Team
2026-4-4
To resolve this issue, explicitly construct unsigned integers
x(:) = (uint8(s(i)) - uint8('0'));
such that the arithmetic expression evaluates to a 8-bit unsigned integer in MATLAB rather than a double.
Please ensure that any expressions present in your generated code do not evaluate to doubles.
After making these changes, regenerate your code.
1 个评论
Walter Roberson
2025-8-28
If you use
int16(s(i)) - int16('0')
then you can handle the possibility that the character is in position 0 through 47. The uint8(s(i)) - uint8('0') form will wrap such positions to uint8(0) which you would not be able to tell apart from the result for input '0'
On the other hand, if you know for sure that the input consists entirely of a mix of '0' and '1' then the uint8 form is fine.
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Create Fixed-Point Objects in MATLAB 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
