I see on quite a few job descriptions for embedded developer positions, that a requirement would be for example to have knowledge of embedded C programming on ARM microcontrollers.
What's not very clear to me is , what is the difference between having knowledge of developing C for a particular ARM processor, or developing C for a PowerPC or other type of processor. Developing with C we are abstracted from the actual instructions which will get compiled and the architecture so why does it really matter?
I would guess that it is important mainly to have knowledge of embedded development, knowing memory constraints etc. and that the actual target processor wouldn't matter too much. For example, won't a developer who was writing code for PowerPC MCUs for many years be just as good as developing code for an ARM-based or other type of MCU?
Perhaps i'm missing something obvious here. Please could someone give an example of what could be some major differences between writing C/C++ code for one type of processor and another type. Thanks
As usual, it depends.
If you are going to develop at a deep C level, it is a good idea to know about the architecture, in order to optimize your code according to speed or/and memory (data bus size, instructions per clock, etc).
It is a must if you are going to develop at a deeper level (and if we are talking about ARM and its thumb, thumb2 and ARM... It is madness).
Furthermore, each architecture because of legacy reasons or to make our life better, adds some tricks. For instance, ARM PC points to the instruction after the next one to be executed, which is quite different in PowerPC or RH850 or whatever.
Above that (I mean, above or close to an OS), the compiler uses to be better than us, but anyway, it is a nice to know how it is working (and definitely it will make the debugging easier)