ICV_BPR1, Interrupt Controller Virtual Binary Point Register 1

The ICV_BPR1 characteristics are:

Purpose

Defines the point at which the priority value fields split into two parts, the group priority field and the subpriority field. The group priority field determines virtual Group 1 interrupt preemption.

Configuration

AArch32 System register ICV_BPR1 bits [31:0] are architecturally mapped to AArch64 System register ICV_BPR1_EL1[31:0].

This register is present only when EL1 is capable of using AArch32, GICv3 is implemented and EL2 is implemented. Otherwise, direct accesses to ICV_BPR1 are UNDEFINED.

Attributes

ICV_BPR1 is a 32-bit register.

Field descriptions

313029282726252423222120191817161514131211109876543210
RES0BinaryPoint

Bits [31:3]

Reserved, RES0.

BinaryPoint, bits [2:0]

If the GIC is configured to use separate binary point fields for Group 0 and Group 1 interrupts, the value of this field controls how the 8-bit interrupt priority field is split into a group priority field, that determines interrupt preemption, and a subpriority field.

For more information about priorities, see 'Priority grouping' in ARM® Generic Interrupt Controller Architecture Specification, GIC architecture version 3.0 and version 4.0 (ARM IHI 0069).

An attempt to program this field to a value less than the minimum value sets the field to the minimum value.

If ICV_CTLR.CBPR is set to 1, Non-secure EL1 reads return ICV_BPR0 + 1 saturated to 0b111. Non-secure EL1 writes are ignored.

If ICV_CTLR.CBPR is set to 1, Secure EL1 reads return ICV_BPR0. Secure EL1 writes modify ICV_BPR0

The reset behavior of this field is:

Accessing ICV_BPR1

The minimum valuse of this register is equal to the minimum value of ICV_BPR0 plus one.

An attempt to program the binary point field to a value less than the minimum value sets the field to the minimum value. On a reset, the binary point field is UNKNOWN.

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

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

coprocopc1CRnCRmopc2
0b11110b0000b11000b11000b011

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && SCR_EL3.IRQ == '1' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR.IRQ == '1' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T12 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T12 == '1' then AArch32.TakeHypTrapException(0x03); elsif ICC_SRE.SRE == '0' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && ICH_HCR_EL2.TALL1 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && ICH_HCR.TALL1 == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.IMO == '1' then R[t] = ICV_BPR1; elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.IMO == '1' then R[t] = ICV_BPR1; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.IRQ == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR.IRQ == '1' then if EL3SDDUndef() then UNDEFINED; else AArch32.TakeMonitorTrapException(); elsif HaveEL(EL3) then R[t] = ICC_BPR1_NS; else R[t] = ICC_BPR1; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && SCR_EL3.IRQ == '1' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && ELUsingAArch32(EL3) && SCR.IRQ == '1' then UNDEFINED; elsif ICC_HSRE.SRE == '0' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.IRQ == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && SCR.IRQ == '1' then if EL3SDDUndef() then UNDEFINED; else AArch32.TakeMonitorTrapException(); elsif HaveEL(EL3) then R[t] = ICC_BPR1_NS; else R[t] = ICC_BPR1; elsif PSTATE.EL == EL3 then if ICC_MSRE.SRE == '0' then UNDEFINED; else if SCR.NS == '0' then R[t] = ICC_BPR1_S; else R[t] = ICC_BPR1_NS;

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

coprocopc1CRnCRmopc2
0b11110b0000b11000b11000b011

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && SCR_EL3.IRQ == '1' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR.IRQ == '1' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T12 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T12 == '1' then AArch32.TakeHypTrapException(0x03); elsif ICC_SRE.SRE == '0' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && ICH_HCR_EL2.TALL1 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && ICH_HCR.TALL1 == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.IMO == '1' then ICV_BPR1 = R[t]; elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.IMO == '1' then ICV_BPR1 = R[t]; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.IRQ == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR.IRQ == '1' then if EL3SDDUndef() then UNDEFINED; else AArch32.TakeMonitorTrapException(); elsif HaveEL(EL3) then ICC_BPR1_NS = R[t]; else ICC_BPR1 = R[t]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && SCR_EL3.IRQ == '1' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && ELUsingAArch32(EL3) && SCR.IRQ == '1' then UNDEFINED; elsif ICC_HSRE.SRE == '0' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.IRQ == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && SCR.IRQ == '1' then if EL3SDDUndef() then UNDEFINED; else AArch32.TakeMonitorTrapException(); elsif HaveEL(EL3) then ICC_BPR1_NS = R[t]; else ICC_BPR1 = R[t]; elsif PSTATE.EL == EL3 then if ICC_MSRE.SRE == '0' then UNDEFINED; else if SCR.NS == '0' then ICC_BPR1_S = R[t]; else ICC_BPR1_NS = R[t];


26/03/2024 09:49; 67c0ae5282a7629ba0ea0ba7267b43cd4f7939f6

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