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ICC_EOIR1

ICC_EOIR1, Interrupt Controller End Of Interrupt Register 1

The ICC_EOIR1 characteristics are:

Purpose

A PE writes to this register to inform the CPU interface that it has completed the processing of the specified Group 1 interrupt.

Configuration

AArch32 System register ICC_EOIR1 bits [31:0] performs the same function as AArch64 System register ICC_EOIR1_EL1[31:0].

This register is present only when FEAT_AA32EL1 is implemented and GICv3 is implemented. Otherwise, direct accesses to ICC_EOIR1 are UNDEFINED.

Attributes

ICC_EOIR1 is a 32-bit register.

Field descriptions

313029282726252423222120191817161514131211109876543210
RES0INTID

Bits [31:24]

Reserved, RES0.

INTID, bits [23:0]

The INTID from the corresponding ICC_IAR1 access.

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

If the EOImode bit for the current Exception level and Security state is 0, a write to this register drops the priority for the interrupt, and also deactivates the interrupt.

If the EOImode bit for the current Exception level and Security state is 1, a write to this register only drops the priority for the interrupt. Software must write to ICC_DIR to deactivate the interrupt.

The appropriate EOImode bit varies as follows:

Accessing ICC_EOIR1

A write to this register must correspond to the most recent valid read by this PE from an Interrupt Acknowledge Register, and must correspond to the INTID that was read from ICC_IAR1, otherwise the system behavior is UNPREDICTABLE. A valid read is a read that returns a valid INTID that is not a special INTID.

A write of a Special INTID is ignored. 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).

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

MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coprocopc1CRnCRmopc2
0b11110b0000b11000b11000b001

if !(IsFeatureImplemented(FEAT_AA32EL1) && IsFeatureImplemented(FEAT_GICv3)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && SCR_EL3().IRQ == '1' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_AA32EL3) && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR().IRQ == '1' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && HSTR_EL2().T12 == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2) && HSTR().T12 == '1' then AArch32_TakeHypTrapException(0x03); elsif ICC_SRE().SRE == '0' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && ICH_HCR_EL2().TALL1 == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2) && ICH_HCR().TALL1 == '1' then AArch32_TakeHypTrapException(0x03); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && HCR_EL2().IMO == '1' then ICV_EOIR1() = R(t); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2) && HCR().IMO == '1' then ICV_EOIR1() = R(t); elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && SCR_EL3().IRQ == '1' then if EL3SDDUndef() then Undefined(); else AArch64_AArch32SystemAccessTrap(EL3, 0x03); end; elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_AA32EL3) && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR().IRQ == '1' then if EL3SDDUndef() then Undefined(); else AArch32_TakeMonitorTrapException(); end; else ICC_EOIR1() = R(t); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && SCR_EL3().IRQ == '1' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_AA32EL3) && ELUsingAArch32(EL3) && SCR().IRQ == '1' then Undefined(); elsif ICC_HSRE().SRE == '0' then Undefined(); elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && SCR_EL3().IRQ == '1' then if EL3SDDUndef() then Undefined(); else AArch64_AArch32SystemAccessTrap(EL3, 0x03); end; elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_AA32EL3) && ELUsingAArch32(EL3) && SCR().IRQ == '1' then if EL3SDDUndef() then Undefined(); else AArch32_TakeMonitorTrapException(); end; else ICC_EOIR1() = R(t); end; elsif PSTATE.EL == EL3 then if ICC_MSRE().SRE == '0' then Undefined(); else ICC_EOIR1() = R(t); end; end;


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

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