SPNU151W January 1998 – March 2023 66AK2E05 , 66AK2H06 , 66AK2H12 , 66AK2H14 , AM1705 , AM1707 , AM1802 , AM1806 , AM1808 , AM1810 , AM5K2E04 , OMAP-L132 , OMAP-L137 , OMAP-L138 , SM470R1B1M-HT , TMS470R1A288 , TMS470R1A384 , TMS470R1A64 , TMS470R1B1M , TMS470R1B512 , TMS470R1B768
The ARM compiler reserves the name space of all identifiers beginning with an underscore ( _ ) or a dollar sign ($). In this dual-state support scheme, all 32-BIS state entry points begin with an underscore, and all 16-BIS state entry points begin with a dollar sign. All other compiler-generated identifiers, which are independent of the state of the processor, begin with an underscore. By this convention, all direct calls within a 16-bit function refer to the entry point beginning with a dollar sign and all direct calls within a 32-bit function refer to the entry point beginning with an underscore.