Arm® A64 Instruction Set Architecture: Armv8, for Armv8-A architecture profile

Library pseudocode for aarch64/debug/takeexceptiondbg/AArch64.TakeExceptionInDebugState

// AArch64.TakeExceptionInDebugState()
// ===================================
// Take an exception in Debug state to an Exception Level using AArch64.

AArch64.TakeExceptionInDebugState(bits(2) target_el, ExceptionRecord exception)
    assert HaveEL(target_el) && !ELUsingAArch32(target_el) && UInt(target_el) >= UInt(PSTATE.EL);

    sync_errors = HaveIESB() && SCTLR[target_el].IESB == '1';
    if HaveDoubleFaultExt() then
        sync_errors = sync_errors || (SCR_EL3.EA == '1' && SCR_EL3.NMEA == '1' && target_el == EL3);
    // SCTLR[].IESB might be ignored in Debug state.
    if !ConstrainUnpredictableBool(Unpredictable_IESBinDebug) then
        sync_errors = FALSE;

    SynchronizeContext();

    // If coming from AArch32 state, the top parts of the X[] registers might be set to zero
    from_32 = UsingAArch32();
    if from_32 then AArch64.MaybeZeroRegisterUppers();
    MaybeZeroSVEUppers(target_el);

    AArch64.ReportException(exception, target_el);

    PSTATE.EL = target_el;
    PSTATE.nRW = '0';
    PSTATE.SP = '1';

    SPSR[] = bits(32) UNKNOWN;
    ELR[] = bits(64) UNKNOWN;

    // PSTATE.{SS,D,A,I,F} are not observable and ignored in Debug state, so behave as if UNKNOWN.
    PSTATE.<SS,D,A,I,F> = bits(5) UNKNOWN;
    PSTATE.IL = '0';
    if from_32 then                             // Coming from AArch32
        PSTATE.IT = '00000000';
        PSTATE.T = '0';                         // PSTATE.J is RES0
    if (HavePANExt() && (PSTATE.EL == EL1 || (PSTATE.EL == EL2 && ELIsInHost(EL0))) &&
        SCTLR[].SPAN == '0') then
        PSTATE.PAN = '1';
    if HaveUAOExt() then PSTATE.UAO = '0';
    if HaveBTIExt() then PSTATE.BTYPE = '00';
    if HaveSSBSExt() then PSTATE.SSBS = bit UNKNOWN;
    if HaveMTEExt() then PSTATE.TCO = '1';

    DLR_EL0 = bits(64) UNKNOWN;
    DSPSR_EL0 = bits(32) UNKNOWN;

    EDSCR.ERR = '1';
    UpdateEDSCRFields();                        // Update EDSCR processor state flags.

    if sync_errors then
        SynchronizeErrors();

    EndOfInstruction();