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TRCIDR8, ID Register 8
The TRCIDR8 characteristics are:
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. Otherwise, direct accesses to TRCIDR8 are UNDEFINED.
Attributes
TRCIDR8 is a 64-bit register.
Field descriptions
The TRCIDR8 bit assignments are:
| 63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32 |
| RES0 | |||||||||||||||||||||||||||||||
| MAXSPEC | |||||||||||||||||||||||||||||||
| 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 |
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.
Accessing the TRCIDR8
Accesses to this register use the following encodings:
MRS <Xt>, TRCIDR8
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b10 | 0b001 | 0b0000 | 0b0000 | 0b110 |
if PSTATE.EL == EL0 then
UNDEFINED;
elsif PSTATE.EL == EL1 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && 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() && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGRTR_EL2.TRCID == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
elsif HaveEL(EL3) && CPTR_EL3.TTA == '1' then
if Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.SystemAccessTrap(EL3, 0x18);
else
return TRCIDR8;
elsif PSTATE.EL == EL2 then
if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && 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 Halted() && EDSCR.SDD == '1' then
UNDEFINED;
else
AArch64.SystemAccessTrap(EL3, 0x18);
else
return TRCIDR8;
elsif PSTATE.EL == EL3 then
if CPTR_EL3.TTA == '1' then
AArch64.SystemAccessTrap(EL3, 0x18);
else
return TRCIDR8;