Personally I find bit-twiddling in C to be painful compared to bit twiddling in assembly.
For my Arduino projects in particular I never make recursive function calls, and would be happy to statically allocate everything in RAM. The stack-oriented activation records in C, calling conventions, return values, are more a problem than a solution.
For call graphs without cycles it should be possible to run static analysis to determine the maximum amount of memory taken by your program at any point, assuming you don't use things like malloc or alloca or dynamically sized arrays.
For my Arduino projects in particular I never make recursive function calls, and would be happy to statically allocate everything in RAM. The stack-oriented activation records in C, calling conventions, return values, are more a problem than a solution.
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