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BRBTS_EL1, Branch Record Buffer Timestamp Register

The BRBTS_EL1 characteristics are:

Purpose

Captures the Timestamp value when branch recording becomes Paused.

Configuration

This register is present only when FEAT_BRBE is implemented. Otherwise, direct accesses to BRBTS_EL1 are UNDEFINED.

Attributes

BRBTS_EL1 is a 64-bit register.

Field descriptions

The BRBTS_EL1 bit assignments are:

6362616059585756555453525150494847464544434241403938373635343332
TS
TS
313029282726252423222120191817161514131211109876543210

TS, bits [63:0]

Timestamp value at time of freezing.

On a Warm reset, this field resets to 0.

Accessing the BRBTS_EL1

Accesses to this register use the following encodings:

MRS <Xt>, BRBTS_EL1

op0op1CRnCRmop2
0b100b0010b10010b00000b010
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'" && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then
        UNDEFINED;
    elsif Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && MDCR_EL3.SBRBE == 'x0' && SCR_EL3.NS == '1' then
        UNDEFINED;
    elsif EL2Enabled() && ((HaveEL(EL3) && SCR_EL3.FGTEn == '0') || HDFGRTR_EL2.nBRBDATA == '0') then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif HaveEL(EL3) && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then
        if Halted() && EDSCR.SDD == '1' then
            UNDEFINED;
        else
            AArch64.SystemAccessTrap(EL3, 0x18);
    elsif HaveEL(EL3) && MDCR_EL3.SBRBE == 'x0' && SCR_EL3.NS == '1' then
        if Halted() && EDSCR.SDD == '1' then
            UNDEFINED;
        else
            AArch64.SystemAccessTrap(EL3, 0x18);
    else
        return BRBTS_EL1;
elsif PSTATE.EL == EL2 then
    if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then
        UNDEFINED;
    elsif Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && MDCR_EL3.SBRBE == 'x0' && SCR_EL3.NS == '1' then
        UNDEFINED;
    elsif HaveEL(EL3) && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then
        if Halted() && EDSCR.SDD == '1' then
            UNDEFINED;
        else
            AArch64.SystemAccessTrap(EL3, 0x18);
    elsif HaveEL(EL3) && MDCR_EL3.SBRBE == 'x0' && SCR_EL3.NS == '1' then
        if Halted() && EDSCR.SDD == '1' then
            UNDEFINED;
        else
            AArch64.SystemAccessTrap(EL3, 0x18);
    else
        return BRBTS_EL1;
elsif PSTATE.EL == EL3 then
    return BRBTS_EL1;
              

MSR BRBTS_EL1, <Xt>

op0op1CRnCRmop2
0b100b0010b10010b00000b010
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'" && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then
        UNDEFINED;
    elsif Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && MDCR_EL3.SBRBE == 'x0' && SCR_EL3.NS == '1' then
        UNDEFINED;
    elsif EL2Enabled() && ((HaveEL(EL3) && SCR_EL3.FGTEn == '0') || HDFGWTR_EL2.nBRBDATA == '0') then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif HaveEL(EL3) && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then
        if Halted() && EDSCR.SDD == '1' then
            UNDEFINED;
        else
            AArch64.SystemAccessTrap(EL3, 0x18);
    elsif HaveEL(EL3) && MDCR_EL3.SBRBE == 'x0' && SCR_EL3.NS == '1' then
        if Halted() && EDSCR.SDD == '1' then
            UNDEFINED;
        else
            AArch64.SystemAccessTrap(EL3, 0x18);
    else
        BRBTS_EL1 = X[t];
elsif PSTATE.EL == EL2 then
    if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then
        UNDEFINED;
    elsif Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && MDCR_EL3.SBRBE == 'x0' && SCR_EL3.NS == '1' then
        UNDEFINED;
    elsif HaveEL(EL3) && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then
        if Halted() && EDSCR.SDD == '1' then
            UNDEFINED;
        else
            AArch64.SystemAccessTrap(EL3, 0x18);
    elsif HaveEL(EL3) && MDCR_EL3.SBRBE == 'x0' && SCR_EL3.NS == '1' then
        if Halted() && EDSCR.SDD == '1' then
            UNDEFINED;
        else
            AArch64.SystemAccessTrap(EL3, 0x18);
    else
        BRBTS_EL1 = X[t];
elsif PSTATE.EL == EL3 then
    BRBTS_EL1 = X[t];