The ICC_BPR0 characteristics are:
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 Group 0 interrupt preemption.
AArch32 System register ICC_BPR0 bits [31:0] are architecturally mapped to AArch64 System register ICC_BPR0_EL1[31:0] .
RW fields in this register reset to architecturally UNKNOWN values.
ICC_BPR0 is a 32-bit register.
The ICC_BPR0 bit assignments are:
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 |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | BinaryPoint |
Reserved, RES0.
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. This is done as follows:
Binary point value | Group priority field | Subpriority field | Field with binary point |
---|---|---|---|
0 | [7:1] | [0] | ggggggg.s |
1 | [7:2] | [1:0] | gggggg.ss |
2 | [7:3] | [2:0] | ggggg.sss |
3 | [7:4] | [3:0] | gggg.ssss |
4 | [7:5] | [4:0] | ggg.sssss |
5 | [7:6] | [5:0] | gg.ssssss |
6 | [7] | [6:0] | g.sssssss |
7 | No preemption | [7:0] | .ssssssss |
This field resets to an architecturally UNKNOWN value.
The minimum binary point value is derived from the number of implemented priority bits. The number of priority bits is IMPLEMENTATION DEFINED, and reported by ICC_CTLR.PRIbits and ICC_MCTLR.PRIbits.
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 set to the minimum supported value.
Accesses to this register use the following encodings:
opc1 | opc2 | CRn | coproc | CRm |
---|---|---|---|---|
0b000 | 0b011 | 0b1100 | 0b1111 | 0b1000 |
if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if 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.TALL0 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && ICH_HCR.TALL0 == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.FMO == '1' then return ICV_BPR0; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR.FMO == '1' then return ICV_BPR0; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.FIQ == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR.FIQ == '1' then AArch32.TakeMonitorTrapException(); else return ICC_BPR0; elsif PSTATE.EL == EL2 then if ICC_HSRE.SRE == '0' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.FIQ == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && SCR.FIQ == '1' then AArch32.TakeMonitorTrapException(); else return ICC_BPR0; elsif PSTATE.EL == EL3 then if ICC_MSRE.SRE == '0' then UNDEFINED; else return ICC_BPR0;
opc1 | opc2 | CRn | coproc | CRm |
---|---|---|---|---|
0b000 | 0b011 | 0b1100 | 0b1111 | 0b1000 |
if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if 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.TALL0 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && ICH_HCR.TALL0 == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.FMO == '1' then ICV_BPR0 = R[t]; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR.FMO == '1' then ICV_BPR0 = R[t]; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.FIQ == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR.FIQ == '1' then AArch32.TakeMonitorTrapException(); else ICC_BPR0 = R[t]; elsif PSTATE.EL == EL2 then if ICC_HSRE.SRE == '0' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.FIQ == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && SCR.FIQ == '1' then AArch32.TakeMonitorTrapException(); else ICC_BPR0 = R[t]; elsif PSTATE.EL == EL3 then if ICC_MSRE.SRE == '0' then UNDEFINED; else ICC_BPR0 = R[t];
13/12/2018 16:42; 6379d01c197f1d40720d32d0f84c419c9187c009
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