29.5 Natural Integers and Fixed Size Integers
UEFI Drivers should only use the integer data types defined in the Calling Conventions section of the UEFI Specification. Even when this recommendation is followed, there is an additional limitation of the EBC architecture. UEFI Drivers with arithmetic calculations and comparisons between following integer types must be avoided:
INTNandUINT8INTNandUINT16INTNandUINT32UINTNandINT64