CCSIDR2, Current Cache Size ID Register 2

The CCSIDR2 characteristics are:

Purpose

Provides information about the architecture of the currently selected cache.

Configuration

AArch32 System register CCSIDR2 bits [31:0] are architecturally mapped to AArch64 System register CCSIDR2_EL1[31:0].

This register is present only when FEAT_CCIDX is implemented and AArch32 is supported at EL1. Otherwise, direct accesses to CCSIDR2 are UNDEFINED.

The implementation includes one CCSIDR2 for each cache that it can access. CSSELR and the Security state select which Cache Size ID Register is accessible.

Attributes

CCSIDR2 is a 32-bit register.

Field descriptions

313029282726252423222120191817161514131211109876543210
RES0NumSets

Bits [31:24]

Reserved, RES0.

NumSets, bits [23:0]

(Number of sets in cache) - 1, therefore a value of 0 indicates 1 set in the cache. The number of sets does not have to be a power of 2.

Accessing CCSIDR2

If CSSELR.Level is programmed to a cache level that is not implemented, then on a read of the CCSIDR2 the behavior is CONSTRAINED UNPREDICTABLE, and can be one of the following:

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

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

coprocopc1CRnCRmopc2
0b11110b0010b00000b00000b010

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T0 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T0 == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TID2 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TID4 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TID2 == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR2.TID4 == '1' then AArch32.TakeHypTrapException(0x03); else return CCSIDR2; elsif PSTATE.EL == EL2 then return CCSIDR2; elsif PSTATE.EL == EL3 then return CCSIDR2;


30/06/2021 15:22; 2a17f7750cfd1ab239f20f6cf29877ba8041794f

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