ICC_HPPIR0

AArch64 System register ICC_HPPIR0_EL1 performs the same function as AArch32 System register ICC_HPPIR0.

This register is present only when FEAT_GICv3 is implemented. Otherwise, direct accesses to ICC_HPPIR0_EL1 are UNDEFINED.

Attributes

Field descriptions

Bits [63:24]

INTID, bits [23:0]

The INTID of the highest priority pending interrupt, if that interrupt is observable at the current Security state and Exception level.

If the highest priority pending interrupt is not observable, this field contains a special INTID to indicate the reason. These special INTIDs can be one of: 1020, 1021, or 1023. For more information, see 'Special INTIDs' in ARM® Generic Interrupt Controller Architecture Specification, GIC architecture version 3.0 and version 4.0 (ARM IHI 0069).

This field has either 16 or 24 bits implemented. The number of implemented bits can be found in ICC_CTLR_EL1.IDbits and ICC_CTLR_EL3.IDbits. If only 16 bits are implemented, bits [23:16] of this register are RES0.

Accessing ICC_HPPIR0_EL1

Accesses to this register use the following encodings in the System register encoding space:

MRS <Xt>, ICC_HPPIR0_EL1

op0	op1	CRn	CRm	op2
0b11	0b000	0b1100	0b1000	0b010

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && SCR_EL3.FIQ == '1' then UNDEFINED; elsif ICC_SRE_EL1.SRE == '0' then AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && ICH_HCR_EL2.TALL0 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && HCR_EL2.FMO == '1' then X[t, 64] = ICV_HPPIR0_EL1; elsif HaveEL(EL3) && SCR_EL3.FIQ == '1' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = ICC_HPPIR0_EL1; elsif PSTATE.EL == EL2 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && SCR_EL3.FIQ == '1' then UNDEFINED; elsif ICC_SRE_EL2.SRE == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && SCR_EL3.FIQ == '1' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = ICC_HPPIR0_EL1; elsif PSTATE.EL == EL3 then if ICC_SRE_EL3.SRE == '0' then AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = ICC_HPPIR0_EL1;

63	62	61	60	59	58	57	56	55	54	53	52	51	50	49	48	47	46	45	44	43	42	41	40	39	38	37	36	35	34	33	32
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
RES0
RES0								INTID

ICC_HPPIR0_EL1, Interrupt Controller Highest Priority Pending Interrupt Register 0