<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE register_page SYSTEM "registers.dtd">
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<register_page>
  <registers>
  
    <register execution_state="AArch32" is_register="True" is_internal="True" is_stub_entry="False">
      <reg_short_name>ICC_IGRPEN0</reg_short_name>
        
        <reg_long_name>Interrupt Controller Interrupt Group 0 Enable register</reg_long_name>



      
            <reg_condition otherwise="UNDEFINED">when FEAT_AA32EL1 is implemented and GICv3 is implemented</reg_condition>
      




          <reg_reset_value></reg_reset_value>

      <reg_mappings>
        



    
      
      <reg_mapping>
        
  

    

  

    <mapped_name filename="AArch64-icc_igrpen0_el1.xml">ICC_IGRPEN0_EL1</mapped_name>
  <mapped_type>Architectural</mapped_type>
      <mapped_execution_state>AArch64</mapped_execution_state>
    <mapped_from_startbit>31</mapped_from_startbit>
    <mapped_from_endbit>0</mapped_from_endbit>
    <mapped_to_startbit>31</mapped_to_startbit>
    <mapped_to_endbit>0</mapped_to_endbit>
    <mapped_from_rangeset output="31:0">
      <range>
        <msb>31</msb>
        <lsb>0</lsb>
      </range>
    </mapped_from_rangeset>
    <mapped_to_rangeset output="31:0">
      <range>
        <msb>31</msb>
        <lsb>0</lsb>
      </range>
    </mapped_to_rangeset>

      </reg_mapping>

      </reg_mappings>

        <reg_purpose>
          
    
      <purpose_text>
        <para>Controls whether Group 0 interrupts are enabled or not.</para>
      </purpose_text>

        </reg_purpose>

      <reg_groups>
            <reg_group>GIC control registers</reg_group>
            <reg_group>GIC</reg_group>
      </reg_groups>
      
      
        
      <reg_attributes>
          
    
      <attributes_text>
        <para>ICC_IGRPEN0 is a 32-bit register.</para>
      </attributes_text>

      </reg_attributes>
      <reg_fieldsets>
        






<fields id="fieldset_0" length="32">
  <text_before_fields/>
  <field id="fieldset_0-31_1" has_partial_fieldset="False" is_linked_to_partial_fieldset="False" is_access_restriction_possible="False" is_variable_length="False" is_constant_value="False" is_partial_field="False" is_conditional_field_name="False" rwtype="RES0">
    <field_msb>31</field_msb>
    <field_lsb>1</field_lsb>
    <rel_range>31:1</rel_range>
    <field_description order="before"/>
    <field_description order="before">
      <para>Reserved, <arm-defined-word>RES0</arm-defined-word>.</para>
    </field_description>
  </field>
  <field id="fieldset_0-0_0" has_partial_fieldset="False" is_linked_to_partial_fieldset="False" is_access_restriction_possible="False" is_variable_length="False" is_constant_value="False" is_partial_field="False" is_conditional_field_name="False">
    <field_name>Enable</field_name>
    <field_msb>0</field_msb>
    <field_lsb>0</field_lsb>
    <rel_range>0</rel_range>
    <field_description order="before">
      <para>Enables Group 0 interrupts.</para>
    </field_description>
    <field_description order="after">
      <para>Virtual accesses to this register update <register_link state="AArch32" id="AArch32-ich_vmcr.xml">ICH_VMCR</register_link>.VENG0.</para>
    </field_description>
    <field_values impdef="False">
      <field_value_instance>
        <field_value>0b0</field_value>
        <field_value_description>
          <para>Group 0 interrupts are disabled.</para>
        </field_value_description>
      </field_value_instance>
      <field_value_instance>
        <field_value>0b1</field_value>
        <field_value_description>
          <para>Group 0 interrupts are enabled.</para>
        </field_value_description>
      </field_value_instance>
    </field_values>
    <field_resets>
      <field_reset reset_type="Warm">
        <field_reset_number>'0'</field_reset_number>
      </field_reset>
    </field_resets>
  </field>
  <text_after_fields/>
</fields>




<reg_fieldset length="32">
  <fieldat id="fieldset_0-31_1" msb="31" lsb="1"/>
  <fieldat id="fieldset_0-0_0" msb="0" lsb="0"/>
</reg_fieldset>


      </reg_fieldsets>

      <access_mechanisms>
          


  
    
      <access_permission_text>
        <para>The lowest Exception level at which this register can be accessed is governed by the Exception level to which FIQ is routed. This routing depends on <xref filename="AS_introduction.fm" linkend="CACIBCFJ">SCR</xref>.FIQ, <xref filename="AS_introduction.fm" linkend="CACIBCFJ">SCR</xref>.NS and <xref filename="AS_introduction.fm" linkend="CACEGEFA">HCR</xref>.FMO.</para>

      </access_permission_text>
      <access_permission_text>
        <para>If an interrupt is pending within the CPU interface when Enable becomes 0, the interrupt must be released to allow the Distributor to forward the interrupt to a different PE.</para>
      </access_permission_text>





    
        
        <access_mechanism accessor="MRC ICC_IGRPEN0" type="SystemAccessor">
            <encoding>
            <access_instruction>MRC{&lt;c&gt;}{&lt;q&gt;} &lt;coproc&gt;, {#}&lt;opc1&gt;, &lt;Rt&gt;, &lt;CRn&gt;, &lt;CRm&gt;{, {#}&lt;opc2&gt;}</access_instruction>
                
                <enc n="coproc" v="0b1111"/>
                
                <enc n="opc1" v="0b000"/>
                
                <enc n="CRn" v="0b1100"/>
                
                <enc n="CRm" v="0b1100"/>
                
                <enc n="opc2" v="0b110"/>
            </encoding>
            <access_permission>
                <ps name="MRC" sections="1" secttype="access_permission">
                <pstext>
if !(IsFeatureImplemented(FEAT_AA32EL1) &amp;&amp; IsFeatureImplemented(FEAT_GICv3)) then
    Undefined();
elsif PSTATE.EL == EL0 then
    Undefined();
elsif PSTATE.EL == EL1 then
    if HaveEL(EL3) &amp;&amp; EL3SDDUndefPriority() &amp;&amp; IsFeatureImplemented(FEAT_AA64EL3) &amp;&amp; !ELUsingAArch32(EL3) &amp;&amp; SCR_EL3().FIQ == '1' then
        Undefined();
    elsif HaveEL(EL3) &amp;&amp; EL3SDDUndefPriority() &amp;&amp; IsFeatureImplemented(FEAT_AA32EL3) &amp;&amp; ELUsingAArch32(EL3) &amp;&amp; PSTATE.M != M32_Monitor &amp;&amp; SCR().FIQ == '1' then
        Undefined();
    elsif EL2Enabled() &amp;&amp; IsFeatureImplemented(FEAT_AA64EL2) &amp;&amp; !ELUsingAArch32(EL2) &amp;&amp; HSTR_EL2().T12 == '1' then
        AArch64_AArch32SystemAccessTrap(EL2, 0x03);
    elsif EL2Enabled() &amp;&amp; IsFeatureImplemented(FEAT_AA32EL2) &amp;&amp; ELUsingAArch32(EL2) &amp;&amp; HSTR().T12 == '1' then
        AArch32_TakeHypTrapException(0x03);
    elsif ICC_SRE().SRE == '0' then
        Undefined();
    elsif EL2Enabled() &amp;&amp; IsFeatureImplemented(FEAT_AA64EL2) &amp;&amp; !ELUsingAArch32(EL2) &amp;&amp; ICH_HCR_EL2().TALL0 == '1' then
        AArch64_AArch32SystemAccessTrap(EL2, 0x03);
    elsif EL2Enabled() &amp;&amp; IsFeatureImplemented(FEAT_AA32EL2) &amp;&amp; ELUsingAArch32(EL2) &amp;&amp; ICH_HCR().TALL0 == '1' then
        AArch32_TakeHypTrapException(0x03);
    elsif EL2Enabled() &amp;&amp; IsFeatureImplemented(FEAT_AA64EL2) &amp;&amp; !ELUsingAArch32(EL2) &amp;&amp; HCR_EL2().FMO == '1' then
        R(t) = ICV_IGRPEN0();
    elsif EL2Enabled() &amp;&amp; IsFeatureImplemented(FEAT_AA32EL2) &amp;&amp; ELUsingAArch32(EL2) &amp;&amp; HCR().FMO == '1' then
        R(t) = ICV_IGRPEN0();
    elsif HaveEL(EL3) &amp;&amp; IsFeatureImplemented(FEAT_AA64EL3) &amp;&amp; !ELUsingAArch32(EL3) &amp;&amp; SCR_EL3().FIQ == '1' then
        if EL3SDDUndef() then
            Undefined();
        else
            AArch64_AArch32SystemAccessTrap(EL3, 0x03);
        end;
    elsif HaveEL(EL3) &amp;&amp; IsFeatureImplemented(FEAT_AA32EL3) &amp;&amp; ELUsingAArch32(EL3) &amp;&amp; PSTATE.M != M32_Monitor &amp;&amp; SCR().FIQ == '1' then
        if EL3SDDUndef() then
            Undefined();
        else
            AArch32_TakeMonitorTrapException();
        end;
    else
        R(t) = ICC_IGRPEN0();
    end;
elsif PSTATE.EL == EL2 then
    if HaveEL(EL3) &amp;&amp; EL3SDDUndefPriority() &amp;&amp; IsFeatureImplemented(FEAT_AA64EL3) &amp;&amp; !ELUsingAArch32(EL3) &amp;&amp; SCR_EL3().FIQ == '1' then
        Undefined();
    elsif HaveEL(EL3) &amp;&amp; EL3SDDUndefPriority() &amp;&amp; IsFeatureImplemented(FEAT_AA32EL3) &amp;&amp; ELUsingAArch32(EL3) &amp;&amp; SCR().FIQ == '1' then
        Undefined();
    elsif ICC_HSRE().SRE == '0' then
        Undefined();
    elsif HaveEL(EL3) &amp;&amp; IsFeatureImplemented(FEAT_AA64EL3) &amp;&amp; !ELUsingAArch32(EL3) &amp;&amp; SCR_EL3().FIQ == '1' then
        if EL3SDDUndef() then
            Undefined();
        else
            AArch64_AArch32SystemAccessTrap(EL3, 0x03);
        end;
    elsif HaveEL(EL3) &amp;&amp; IsFeatureImplemented(FEAT_AA32EL3) &amp;&amp; ELUsingAArch32(EL3) &amp;&amp; SCR().FIQ == '1' then
        if EL3SDDUndef() then
            Undefined();
        else
            AArch32_TakeMonitorTrapException();
        end;
    else
        R(t) = ICC_IGRPEN0();
    end;
elsif PSTATE.EL == EL3 then
    if ICC_MSRE().SRE == '0' then
        Undefined();
    else
        R(t) = ICC_IGRPEN0();
    end;
end;
                </pstext>
                </ps>
            </access_permission>
        </access_mechanism>
    
        
        <access_mechanism accessor="MCR ICC_IGRPEN0" type="SystemAccessor">
            <encoding>
            <access_instruction>MCR{&lt;c&gt;}{&lt;q&gt;} &lt;coproc&gt;, {#}&lt;opc1&gt;, &lt;Rt&gt;, &lt;CRn&gt;, &lt;CRm&gt;{, {#}&lt;opc2&gt;}</access_instruction>
                
                <enc n="coproc" v="0b1111"/>
                
                <enc n="opc1" v="0b000"/>
                
                <enc n="CRn" v="0b1100"/>
                
                <enc n="CRm" v="0b1100"/>
                
                <enc n="opc2" v="0b110"/>
            </encoding>
            <access_permission>
                <ps name="MCR" sections="1" secttype="access_permission">
                <pstext>
if !(IsFeatureImplemented(FEAT_AA32EL1) &amp;&amp; IsFeatureImplemented(FEAT_GICv3)) then
    Undefined();
elsif PSTATE.EL == EL0 then
    Undefined();
elsif PSTATE.EL == EL1 then
    if HaveEL(EL3) &amp;&amp; EL3SDDUndefPriority() &amp;&amp; IsFeatureImplemented(FEAT_AA64EL3) &amp;&amp; !ELUsingAArch32(EL3) &amp;&amp; SCR_EL3().FIQ == '1' then
        Undefined();
    elsif HaveEL(EL3) &amp;&amp; EL3SDDUndefPriority() &amp;&amp; IsFeatureImplemented(FEAT_AA32EL3) &amp;&amp; ELUsingAArch32(EL3) &amp;&amp; PSTATE.M != M32_Monitor &amp;&amp; SCR().FIQ == '1' then
        Undefined();
    elsif EL2Enabled() &amp;&amp; IsFeatureImplemented(FEAT_AA64EL2) &amp;&amp; !ELUsingAArch32(EL2) &amp;&amp; HSTR_EL2().T12 == '1' then
        AArch64_AArch32SystemAccessTrap(EL2, 0x03);
    elsif EL2Enabled() &amp;&amp; IsFeatureImplemented(FEAT_AA32EL2) &amp;&amp; ELUsingAArch32(EL2) &amp;&amp; HSTR().T12 == '1' then
        AArch32_TakeHypTrapException(0x03);
    elsif ICC_SRE().SRE == '0' then
        Undefined();
    elsif EL2Enabled() &amp;&amp; IsFeatureImplemented(FEAT_AA64EL2) &amp;&amp; !ELUsingAArch32(EL2) &amp;&amp; ICH_HCR_EL2().TALL0 == '1' then
        AArch64_AArch32SystemAccessTrap(EL2, 0x03);
    elsif EL2Enabled() &amp;&amp; IsFeatureImplemented(FEAT_AA32EL2) &amp;&amp; ELUsingAArch32(EL2) &amp;&amp; ICH_HCR().TALL0 == '1' then
        AArch32_TakeHypTrapException(0x03);
    elsif EL2Enabled() &amp;&amp; IsFeatureImplemented(FEAT_AA64EL2) &amp;&amp; !ELUsingAArch32(EL2) &amp;&amp; HCR_EL2().FMO == '1' then
        ICV_IGRPEN0() = R(t);
    elsif EL2Enabled() &amp;&amp; IsFeatureImplemented(FEAT_AA32EL2) &amp;&amp; ELUsingAArch32(EL2) &amp;&amp; HCR().FMO == '1' then
        ICV_IGRPEN0() = R(t);
    elsif HaveEL(EL3) &amp;&amp; IsFeatureImplemented(FEAT_AA64EL3) &amp;&amp; !ELUsingAArch32(EL3) &amp;&amp; SCR_EL3().FIQ == '1' then
        if EL3SDDUndef() then
            Undefined();
        else
            AArch64_AArch32SystemAccessTrap(EL3, 0x03);
        end;
    elsif HaveEL(EL3) &amp;&amp; IsFeatureImplemented(FEAT_AA32EL3) &amp;&amp; ELUsingAArch32(EL3) &amp;&amp; PSTATE.M != M32_Monitor &amp;&amp; SCR().FIQ == '1' then
        if EL3SDDUndef() then
            Undefined();
        else
            AArch32_TakeMonitorTrapException();
        end;
    else
        ICC_IGRPEN0() = R(t);
    end;
elsif PSTATE.EL == EL2 then
    if HaveEL(EL3) &amp;&amp; EL3SDDUndefPriority() &amp;&amp; IsFeatureImplemented(FEAT_AA64EL3) &amp;&amp; !ELUsingAArch32(EL3) &amp;&amp; SCR_EL3().FIQ == '1' then
        Undefined();
    elsif HaveEL(EL3) &amp;&amp; EL3SDDUndefPriority() &amp;&amp; IsFeatureImplemented(FEAT_AA32EL3) &amp;&amp; ELUsingAArch32(EL3) &amp;&amp; SCR().FIQ == '1' then
        Undefined();
    elsif ICC_HSRE().SRE == '0' then
        Undefined();
    elsif HaveEL(EL3) &amp;&amp; IsFeatureImplemented(FEAT_AA64EL3) &amp;&amp; !ELUsingAArch32(EL3) &amp;&amp; SCR_EL3().FIQ == '1' then
        if EL3SDDUndef() then
            Undefined();
        else
            AArch64_AArch32SystemAccessTrap(EL3, 0x03);
        end;
    elsif HaveEL(EL3) &amp;&amp; IsFeatureImplemented(FEAT_AA32EL3) &amp;&amp; ELUsingAArch32(EL3) &amp;&amp; SCR().FIQ == '1' then
        if EL3SDDUndef() then
            Undefined();
        else
            AArch32_TakeMonitorTrapException();
        end;
    else
        ICC_IGRPEN0() = R(t);
    end;
elsif PSTATE.EL == EL3 then
    if ICC_MSRE().SRE == '0' then
        Undefined();
    else
        ICC_IGRPEN0() = R(t);
    end;
end;
                </pstext>
                </ps>
            </access_permission>
        </access_mechanism>

      </access_mechanisms>

      <arch_variants>
      </arch_variants>
  </register>
</registers>
<timestamp>2026-03-26 20:27:25</timestamp>
<commit_id>2026-03_rel</commit_id>
</register_page>