17.2.28 Tcm Function Attribute

The tcm attribute instructs the compiler to place the function in tightly-coupled memory (TCM), if possible, providing highly consistent access times. The actual section will be determined by the compiler, possibly based on other attributes such as space. For example:

void __attribute__((tcm)) foo (void) {return;}

In the above example, the compiler will attempt to place foo in the itcm memory section, or the tcm section on those processors where the code and data memory spaces are combined. Note that the amount of TCM available in program or data memory on the target device may vary, so the compiler cannot ensure all functions with the tcm attribute can be placed in TCM.

Also see Tightly-Coupled Memories.