Where can i find IOR/IOW macros ?

Alternatively define a C struct that maps your device registers.

Define an 'extern' variable of that type.

Use the linker to place the variable at the correct address - setting the high address bit if you have the data cache enabled.

You either need to make the structure members 'volatile', or put 'asm volatile("" ::: "memory")' in the C source at appropriate points to ensure gcc doesn't have any values cached in registers.

Note that gcc generates additional instrctions for 8 and 16 bit volatile data.