incompatible type for argument 2 of '__builtin_stwio'

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Personally I wouldn't ever have written anything like IOWR_32DIRECT() or any of its friends.

It is much, much, much safer to define C structures to map device registers and then either use a pointer initialiased to the correct value or get the linker to assign a constant to a normal C structure variable.

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This was taken from section 9-4 of the nios ii software developers handbook:

"The HAL provides the C-language macros IORD and IOWR that expand to the

appropriate assembly instructions to bypass the data cache. The IORD macro expands

to the ldwio instruction, and the IOWR macro expands to the stwio instruction. These

macros are provided to enable HAL device drivers to access device registers."

Can you explain how using the macro expansion IOWR_32DIRECT() is different?

thanks,

Drew