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GICD_ICFGR<n>

GICD_ICFGR<n>, Interrupt Configuration Registers, n = 0 - 63

The GICD_ICFGR<n> characteristics are:

Purpose

Determines whether the corresponding interrupt is edge-triggered or level-sensitive.

Configuration

These registers are available in all GIC configurations. If the GIC implementation supports two Security states, these registers are Common.

GICD_ICFGR1 is Banked for each connected PE with GICR_TYPER.Processor_Number < 8.

Accessing GICD_ICFGR1 from a PE with GICR_TYPER.Processor_Number > 7 is CONSTRAINED UNPREDICTABLE:

Register is RAZ/WI.
An UNKNOWN banked copy of the register is accessed.

For SGIs and PPIs:

When ARE is 1 for the Security state of an interrupt, the field for that interrupt is RES0 and an implementation is permitted to make the field RAZ/WI in this case.
Equivalent functionality is provided by GICR_ICFGR<n>

For each supported PPI, it is IMPLEMENTATION DEFINED whether software can program the corresponding Int_config field.

For SGIs, Int_config fields are RO, meaning that GICD_ICFGR0 is RO.

Changing Int_config when the interrupt is individually enabled is UNPREDICTABLE.

Changing the interrupt configuration between level-sensitive and edge-triggered (in either direction) at a time when there is a pending interrupt will leave the interrupt in an UNKNOWN pending state.

Fields corresponding to unimplemented interrupts are RAZ/WI.

Attributes

GICD_ICFGR<n> is a 32-bit register.

Field descriptions

31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
Int_config15		Int_config14		Int_config13		Int_config12		Int_config11		Int_config10		Int_config9		Int_config8		Int_config7		Int_config6		Int_config5		Int_config4		Int_config3		Int_config2		Int_config1		Int_config0

Int_config<x>, bits [2x+1:2x], for x = 15 to 0

Indicates whether the interrupt is level-sensitive or edge-triggered.

Int_config<x>	Meaning
0b00	Corresponding interrupt is level-sensitive.
0b10	Corresponding interrupt is edge-triggered.

Int_config[0] (bit [2x]) is RES0.

For SGIs, this field always indicates edge-triggered.

The reset behavior of this field is:

On a GIC reset, this field resets to an architecturally UNKNOWN value.

Accessing GICD_ICFGR<n>

For SPIs and PPIs, when GICD_CTLR.DS==0, a register bit that corresponds to a Group 0 or Secure Group 1 interrupt is RAZ/WI to Non-secure accesses.

GICD_ICFGR<n> can be accessed through the memory-mapped interfaces:

Component	Frame	Offset	Instance
GIC Distributor	Dist_base	0x0C00 + (4 * n)	GICD_ICFGR<n>

Accesses to this register are RW.

2026-03-26 20:27:25, 2026-03_rel