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# DBGDTR_EL0, Debug Data Transfer Register, half-duplex

The DBGDTR_EL0 characteristics are:

## Purpose

Transfers 64 bits of data between the PE and an external debugger. Can transfer both ways using only a single register.

## Configuration

AArch64 System register DBGDTR_EL0 bits [63:32] are architecturally mapped to AArch32 System register DBGDTRRXint[31:0] when written.

AArch64 System register DBGDTR_EL0 bits [63:32] are architecturally mapped to External register DBGDTRRX_EL0[31:0] when written.

AArch64 System register DBGDTR_EL0 bits [63:32] are architecturally mapped to AArch64 System register DBGDTRRX_EL0[31:0] when written.

AArch64 System register DBGDTR_EL0 bits [31:0] are architecturally mapped to AArch32 System register DBGDTRTXint[31:0] when written.

AArch64 System register DBGDTR_EL0 bits [31:0] are architecturally mapped to External register DBGDTRTX_EL0[31:0] when written.

AArch64 System register DBGDTR_EL0 bits [31:0] are architecturally mapped to AArch64 System register DBGDTRTX_EL0[31:0] when written.

AArch64 System register DBGDTR_EL0 bits [63:32] are architecturally mapped to AArch32 System register DBGDTRTXint[31:0] when read.

AArch64 System register DBGDTR_EL0 bits [63:32] are architecturally mapped to External register DBGDTRTX_EL0[31:0] when read.

AArch64 System register DBGDTR_EL0 bits [63:32] are architecturally mapped to AArch64 System register DBGDTRTX_EL0[31:0] when read.

AArch64 System register DBGDTR_EL0 bits [31:0] are architecturally mapped to AArch32 System register DBGDTRRXint[31:0] when read.

AArch64 System register DBGDTR_EL0 bits [31:0] are architecturally mapped to External register DBGDTRRX_EL0[31:0] when read.

AArch64 System register DBGDTR_EL0 bits [31:0] are architecturally mapped to AArch64 System register DBGDTRRX_EL0[31:0] when read.

## Attributes

DBGDTR_EL0 is a 64-bit register.

## Field descriptions

The DBGDTR_EL0 bit assignments are:

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
HighWord
LowWord
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

#### HighWord, bits [63:32]

Writes to this register set DTRRX to the value in this field and do not change RXfull.

Reads of this register:

- If RXfull is set to 1, return the last value written to DTRTX.

- If RXfull is set to 0, return an UNKNOWN value.

After the read, RXfull is cleared to 0.

#### LowWord, bits [31:0]

Writes to this register set DTRTX to the value in this field and set TXfull to 1.

Reads of this register:

- If RXfull is set to 1, return the last value written to DTRRX.

- If RXfull is set to 0, return an UNKNOWN value.

After the read, RXfull is cleared to 0.

## Accessing the DBGDTR_EL0

Accesses to this register use the following encodings:

#### MRS <Xt>, DBGDTR_EL0

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b10 | 0b011 | 0b0000 | 0b0100 | 0b000

if PSTATE.EL == EL0 then if !ELUsingAArch32(EL1) && MDSCR_EL1.TDCC == '1' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && (HCR_EL2.TGE == '1' || MDCR_EL2.<TDE,TDA> != '00') then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else return DBGDTR_EL0; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.<TDE,TDA> != '00' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else return DBGDTR_EL0; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else return DBGDTR_EL0; elsif PSTATE.EL == EL3 then return DBGDTR_EL0;

#### MSR DBGDTR_EL0, <Xt>

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b10 | 0b011 | 0b0000 | 0b0100 | 0b000

if PSTATE.EL == EL0 then if !ELUsingAArch32(EL1) && MDSCR_EL1.TDCC == '1' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && (HCR_EL2.TGE == '1' || MDCR_EL2.<TDE,TDA> != '00') then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else DBGDTR_EL0 = X[t]; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.<TDE,TDA> != '00' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else DBGDTR_EL0 = X[t]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else DBGDTR_EL0 = X[t]; elsif PSTATE.EL == EL3 then DBGDTR_EL0 = X[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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