_SHM_ID_BITS 25 include/asm-m68k/shm.h #define SHM_ID_MASK ((1<<_SHM_ID_BITS)-1) _SHM_ID_BITS 27 include/asm-m68k/shm.h #define SHM_IDX_SHIFT (SHM_ID_SHIFT+_SHM_ID_BITS)