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# DBGDTRTXext, Debug OS Lock Data Transfer Register, Transmit

The DBGDTRTXext characteristics are:

## Purpose

Used for save/restore of DBGDTRTXint. It is a component of the Debug Communication Channel.

## Configuration

AArch32 System register DBGDTRTXext bits [31:0] are architecturally mapped to AArch64 System register OSDTRTX_EL1[31:0] .

RW fields in this register reset to architecturally UNKNOWN values.

## Attributes

DBGDTRTXext is a 32-bit register.

## Field descriptions

The DBGDTRTXext 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
Return DTRTX without side-effect

#### Bits [31:0]

Return DTRTX without side-effect.

Reads of this register return the value in DTRTX and do not change TXfull.

Writes of this register update the value in DTRTX and do not change TXfull.

For the full behavior of the Debug Communications Channel, see 'The Debug Communication Channel and Instruction Transfer Register' in the Arm® Architecture Reference Manual, Armv8, for Armv8-A architecture profile, chapter H4.

On a Cold reset, this field resets to an architecturally UNKNOWN value.

## Accessing the DBGDTRTXext

Arm deprecates reads and writes of DBGDTRTXext through the System register interface when the OS Lock is unlocked, DBGOSLSR.OSLK == 0.

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 | 0b0011 | 0b010

if PSTATE.EL == EL0 then UNDEFINED; 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 DBGDTRTXext; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x05); else return DBGDTRTXext; elsif PSTATE.EL == EL3 then return DBGDTRTXext;

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

coproc | opc1 | CRn | CRm | opc2
--- | --- | --- | --- | ---
0b1110 | 0b000 | 0b0000 | 0b0011 | 0b010

if PSTATE.EL == EL0 then UNDEFINED; 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 DBGDTRTXext = R[t]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x05); else DBGDTRTXext = R[t]; elsif PSTATE.EL == EL3 then DBGDTRTXext = R[t];

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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