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# DBGDSCRint, Debug Status and Control Register, Internal View

The DBGDSCRint characteristics are:

## Purpose

Main control register for the debug implementation. This is an internal, read-only view.

## Configuration

AArch32 System register DBGDSCRint bits [30:29] are architecturally mapped to AArch64 System register MDCCSR_EL0[30:29] .

AArch32 System register DBGDSCRint bits [15:2] are architecturally mapped to AArch32 System register DBGDSCRext[15:2] .

This register is required in all implementations.

DBGDSCRint.{NS, SPNIDdis, SPIDdis, MDBGen, UDCCdis, MOE} are UNKNOWN when the register is accessed at EL0. However, although these values are not accessible at EL0 by instructions that are neither UNPREDICTABLE nor return UNKNOWN values, it is permissible for an implementation to return the values of DBGDSCRext.{NS, SPNIDdis, SPIDdis, MDBGen, UDCCdis, MOE} for these fields at EL0.

It is also permissible for an implementation to return the same values as defined for a read of DBGDSCRint at EL1 or above. (This is the case even if the implementation does not support AArch32 at EL1 or above.)

## Attributes

DBGDSCRint is a 32-bit register.

## Field descriptions

The DBGDSCRint bit assignments are:

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 | RXfull | TXfull | RES0 | NS | SPNIDdis | SPIDdis | MDBGen | RES0 | UDCCdis | RES0 | MOE | RES0

#### Bit [31]

Reserved, RES0.

#### RXfull, bit [30]

DTRRX full. Read-only view of the equivalent bit in the EDSCR.

#### TXfull, bit [29]

DTRTX full. Read-only view of the equivalent bit in the EDSCR.

#### Bits [28:19]

Reserved, RES0.

#### NS, bit [18]

Non-secure status.

Read-only view of the equivalent bit in the DBGDSCRext. Arm deprecates use of this field.

#### SPNIDdis, bit [17]

Secure privileged non-invasive debug disable.

Read-only view of the equivalent bit in the DBGDSCRext. Arm deprecates use of this field.

#### SPIDdis, bit [16]

Secure privileged invasive debug disable.

Read-only view of the equivalent bit in the DBGDSCRext. Arm deprecates use of this field.

#### MDBGen, bit [15]

Monitor debug events enable.

Read-only view of the equivalent bit in the DBGDSCRext.

#### Bits [14:13]

Reserved, RES0.

#### UDCCdis, bit [12]

User mode access to Debug Communications Channel disable.

Read-only view of the equivalent bit in the DBGDSCRext. Arm deprecates use of this field.

#### Bits [11:6]

Reserved, RES0.

#### MOE, bits [5:2]

Method of Entry for debug exception. When a debug exception is taken to an Exception level using AArch32, this field is set to indicate the event that caused the exception:

MOE | Meaning
--- | ---
0b0001 | Breakpoint
0b0011 | Software breakpoint (BKPT) instruction
0b0101 | Vector catch
0b1010 | Watchpoint

Read-only view of the equivalent bit in the DBGDSCRext.

#### Bits [1:0]

Reserved, RES0.

## Accessing the DBGDSCRint

Accesses to this register use the following encodings:

#### MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coproc | opc1 | CRn | CRm | opc2
--- | --- | --- | --- | ---
0b1110 | 0b000 | 0b0000 | 0b0001 | 0b000

if PSTATE.EL == EL0 then if !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,TDA> != '00') then AArch64.AArch32SystemAccessTrap(EL2, 0x05); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x05); else return DBGDSCRint; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.<TDE,TDA> != '00' then AArch64.AArch32SystemAccessTrap(EL2, 0x05); elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.<TDE,TDA> != '00' then AArch32.TakeHypTrapException(0x05); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x05); else return DBGDSCRint; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x05); else return DBGDSCRint; elsif PSTATE.EL == EL3 then return DBGDSCRint;

AArch32 Registers | AArch64 Registers | AArch32 Instructions | AArch64 Instructions | Index by Encoding | External Registers | External Registers by Offset | Registers by Functional Group | Proprietary Notice

15/04/2019 16:47; 8c23526ba8a13a72aada4137daf3e3977b49036e

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