All quantities must be aligned on their natural boundaries, using standard C data types:
short integers are aligned on 16-bit boundaries.
int integers are aligned on 32-bit boundaries.
long integers are aligned on 64-bit boundaries for SPARC systems. For information on data models, see Appendix C, Making a Device Driver 64-Bit Ready.
long long integers are aligned on 64-bit boundaries.
Usually, the compiler handles any alignment issues. However, driver writers are more likely to be concerned about alignment because the proper data types must be used to access the devices. Because device registers are commonly accessed through a pointer reference, drivers must ensure that pointers are properly aligned when accessing the device.