Defines the base physical address of a 4KB-aligned memory-mapped debug component, usually a ROM table that locates and describes the memory-mapped debug components in the system. Armv8 deprecates any use of this register.
AArch32 System register DBGDRAR bits [63:0] are architecturally mapped to AArch64 System register MDRAR_EL1[63:0].
This register is present only when AArch32 is supported. Otherwise, direct accesses to DBGDRAR are UNDEFINED.
DBGDRAR is a 64-bit register that can also be accessed as a 32-bit value. If it is accessed as a 32-bit register, bits [31:0] are read.
If EL1 cannot use AArch32 then the implementation of this register is OPTIONAL and deprecated.
DBGDRAR is a 64-bit register.
| 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 |
| 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 |
| RES0 | ROMADDR[47:12] | ||||||||||||||||||||||||||||||
| ROMADDR[47:12] | RES0 | Valid | |||||||||||||||||||||||||||||
Reserved, RES0.
Bits[47:12] of the ROM table physical address.
If the physical address size in bits (PAsize) is less than 48 then the register bits corresponding to ROMADDR [47:PAsize] are RES0.
Bits [11:0] of the ROM table physical address are zero.
Arm strongly recommends that bits ROMADDR[(PAsize-1):32] are zero in any system where the implementation only supports execution in AArch32 state.
If DBGDRAR.Valid == 0b00, then this field is UNKNOWN.
In an implementation that includes EL3, ROMADDR is an address in Non-secure memory. It is IMPLEMENTATION DEFINED whether the ROM table is also accessible in Secure memory.
Reserved, RES0.
This field indicates whether the ROM Table address is valid.
| Valid | Meaning |
|---|---|
| 0b00 |
ROM Table address is not valid. Software must ignore ROMADDR. |
| 0b11 |
ROM Table address is valid. |
Other values are reserved.
Arm recommends implementations set this field to zero.
Accesses to this register use the following encodings in the System register encoding space:
MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}
| coproc | opc1 | CRn | CRm | opc2 |
|---|---|---|---|---|
| 0b1110 | 0b000 | 0b0001 | 0b0000 | 0b000 |
if Halted() && ConstrainUnpredictableBool(Unpredictable_IGNORETRAPINDEBUG) then R[t] = DBGDRAR<31:0>; elsif PSTATE.EL == EL0 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then UNDEFINED; elsif !ELUsingAArch32(EL1) && MDSCR_EL1.TDCC == '1' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x05); else AArch64.AArch32SystemAccessTrap(EL1, 0x05); elsif ELUsingAArch32(EL1) && DBGDSCRext.UDCCdis == '1' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x05); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then AArch32.TakeHypTrapException(0x00); else UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && (HCR_EL2.TGE == '1' || MDCR_EL2.<TDE,TDRA> != '00') then AArch64.AArch32SystemAccessTrap(EL2, 0x05); elsif EL2Enabled() && ELUsingAArch32(EL2) && (HCR.TGE == '1' || HDCR.<TDE,TDRA> != '00') then AArch32.TakeHypTrapException(0x05); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x05); else R[t] = DBGDRAR<31:0>; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.<TDE,TDRA> != '00' then AArch64.AArch32SystemAccessTrap(EL2, 0x05); elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.<TDE,TDRA> != '00' then AArch32.TakeHypTrapException(0x05); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x05); else R[t] = DBGDRAR<31:0>; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x05); else R[t] = DBGDRAR<31:0>; elsif PSTATE.EL == EL3 then R[t] = DBGDRAR<31:0>;
MRRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <Rt2>, <CRm>
| coproc | CRm | opc1 |
|---|---|---|
| 0b1110 | 0b0001 | 0b0000 |
if Halted() && ConstrainUnpredictableBool(Unpredictable_IGNORETRAPINDEBUG) then (R[t2], R[t]) = (DBGDRAR<63:32>, DBGDRAR<31:0>); elsif PSTATE.EL == EL0 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then UNDEFINED; elsif !ELUsingAArch32(EL1) && MDSCR_EL1.TDCC == '1' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x0C); else AArch64.AArch32SystemAccessTrap(EL1, 0x0C); elsif ELUsingAArch32(EL1) && DBGDSCRext.UDCCdis == '1' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x0C); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then AArch32.TakeHypTrapException(0x00); else UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && (HCR_EL2.TGE == '1' || MDCR_EL2.<TDE,TDRA> != '00') then AArch64.AArch32SystemAccessTrap(EL2, 0x0C); elsif EL2Enabled() && ELUsingAArch32(EL2) && (HCR.TGE == '1' || HDCR.<TDE,TDRA> != '00') then AArch32.TakeHypTrapException(0x0C); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x0C); else (R[t2], R[t]) = (DBGDRAR<63:32>, DBGDRAR<31:0>); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.<TDE,TDRA> != '00' then AArch64.AArch32SystemAccessTrap(EL2, 0x0C); elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.<TDE,TDRA> != '00' then AArch32.TakeHypTrapException(0x0C); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x0C); else (R[t2], R[t]) = (DBGDRAR<63:32>, DBGDRAR<31:0>); elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x0C); else (R[t2], R[t]) = (DBGDRAR<63:32>, DBGDRAR<31:0>); elsif PSTATE.EL == EL3 then (R[t2], R[t]) = (DBGDRAR<63:32>, DBGDRAR<31:0>);