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TRCIDR8: Trace ID Register 8

Purpose

Returns the maximum speculation depth of the instruction trace element stream.

Configuration

AArch64 System register TRCIDR8 bits [31:0] are architecturally mapped to External register TRCIDR8[31:0].

This register is present only when FEAT_ETE is implemented and System register access to the trace unit registers is implemented. Otherwise, direct accesses to TRCIDR8 are UNDEFINED.

Attributes

TRCIDR8 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
RES0
MAXSPEC

Bits [63:32]

Reserved, RES0.

MAXSPEC, bits [31:0]

Indicates the maximum speculation depth of the instruction trace element stream. This is the maximum number of P0 elements in the trace element stream that can be speculative at any time.

This field has an IMPLEMENTATION DEFINED value.

Access to this field is RO.

Accessing TRCIDR8

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

MRS <Xt>, TRCIDR8

op0op1CRnCRmop2
0b100b0010b00000b00000b110

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && CPTR_EL3.TTA == '1' then UNDEFINED; elsif CPACR_EL1.TTA == '1' then AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && CPTR_EL2.TTA == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGRTR_EL2.TRCID == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && CPTR_EL3.TTA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif IsFeatureImplemented(FEAT_TRBE_EXT) && OSLSR_EL1.OSLK == '0' && HaltingAllowed() && EDSCR2.TTA == '1' then Halt(DebugHalt_SoftwareAccess); else X[t, 64] = TRCIDR8; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && CPTR_EL3.TTA == '1' then UNDEFINED; elsif CPTR_EL2.TTA == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && CPTR_EL3.TTA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif !ELUsingAArch32(EL1) && IsFeatureImplemented(FEAT_TRBE_EXT) && OSLSR_EL1.OSLK == '0' && HaltingAllowed() && EDSCR2.TTA == '1' then Halt(DebugHalt_SoftwareAccess); else X[t, 64] = TRCIDR8; elsif PSTATE.EL == EL3 then if CPTR_EL3.TTA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); elsif !ELUsingAArch32(EL1) && IsFeatureImplemented(FEAT_TRBE_EXT) && OSLSR_EL1.OSLK == '0' && HaltingAllowed() && EDSCR2.TTA == '1' then Halt(DebugHalt_SoftwareAccess); else X[t, 64] = TRCIDR8;