Here are some general rules for interfacing with C. Comments about the 9900 version of GCC are just guesses.   C variables are normally allocated on the stack. Any other memory use would probably be through allocation routines and it is accessed through pointers. Perhaps you could specify scratchpad memory in a call to the memory allocation routine similar to how the Amiga allowed allocation of CHIP (graphics) or FAST memory. Due to scratch-pad's limited size and importance I would suggest
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