The GIC has three primary memory regions:
- Arm GIC-500 region 0
- Used for normal (non-ITS) GIC register accesses (GICD_* and GITS_* register spaces)
- Referred to as awuser_s[3]/aruser_s[3] = 0 in the Arm GIC-500 TRM
- Arm GIC-500 region 1
- Used for ITS translation service register accesses (GITS_TRANSLATER)
- Referred to as awuser_s[3]/aruser_s[3] = 1 in the Arm GIC-500 TRM
- GIC ECC aggregator region