Hi,
Being new to the fascinating ARM world, I am going through various documentation and reading material.
I read that the ARM Cortex-M processors (or I think it applies to all the Cortex processors) are entirely C programmable. This means that assembly code is not required for start-up code and for ISRs.
I am curious to find out what prohibits the earlier ARM processors (or even other architectures) to write the start-up code in C? Are these any specific instructions? One which I found was the WFI (Wait For Interrupt) which can't have an equivalent in C. But that is not a start-up or ISR instruction.
Thanks for your support !
Gopal
Especially since it would have been a lot easier to add it as a primitive than going through the effort of recognizing an expression which implements a rol/ror using other bitwise ops (which is what all decent C compilers do).