53 lines
1.2 KiB
Markdown
53 lines
1.2 KiB
Markdown
# Some common mistakes
|
|
|
|
## Bit-width mismatch
|
|
|
|
That is, the bit-width of the LHS and RHS of an assignment operation are different.
|
|
For example, the following code will result in compile error:
|
|
|
|
```cpp
|
|
Register <8> r1;
|
|
Register <16> r2;
|
|
r1 <= r2; // Error: bit-width mismatch
|
|
```
|
|
|
|
## Register/Wire passed by value
|
|
|
|
Register/Wire can be only passed by reference. We forbid
|
|
the copy/move constructor for Register/Wire to avoid misuse.
|
|
|
|
This may cause some error in the lambda function of a wire.
|
|
|
|
```cpp
|
|
Register <8> r1;
|
|
Wire <8> w1 = [&]() { return r1; };
|
|
```
|
|
|
|
To fix this issue, you may return by reference,
|
|
or use + operator to convert the value to bit type.
|
|
|
|
```cpp
|
|
Register <8> r1;
|
|
Wire <8> w1 = [&]() -> auto & { return r1; };
|
|
Wire <8> w2 = [&]() { return +r1; };
|
|
```
|
|
|
|
## C-array as member variable
|
|
|
|
We do not support C-array as member variable for synchronization.
|
|
Our C++ static reflection library do not support parsing
|
|
C-array as member variable currently.
|
|
|
|
Always use `std::array` instead.
|
|
|
|
```cpp
|
|
struct NeedToSync {
|
|
std::array <Register <1>, 8> data;
|
|
std::array <Wire <1>, 8> data2;
|
|
};
|
|
```
|
|
|
|
## Some others
|
|
|
|
If you encounter some other issues, please feel free to open an issue.
|