All the asm macro names that convert a particular architecture to a generic
interface now follow the convention whereby the "destination" (usually a
register) is specified first.
For archs that have 16-bit pointers, the asmxtensa.h file can give compiler
warnings about left-shift being greater than the width of the type (due to
the inline functions in this header file). Explicitly casting the
constants to uint32_t stops these warnings.