The Cosmic compiler uses the @interrupt syntax, whereas this compiler employs the interrupt syntax. To keep the source base portable, you can use a macro (for example, in a main header file, which selects the correct syntax depending on the compiler used).
/* place the following in a header file: */ #ifdef __MWERKS__ #define INTERRUPT interrupt #else #define INTERRUPT @interrupt #endif /* now for each @interrupt we use the INTERRUPT macro: */ void INTERRUPT myISRFunction(void) { ....