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# OSDTRTX_EL1, OS Lock Data Transfer Register, Transmit

The OSDTRTX_EL1 characteristics are:

## Purpose

Used for save/restore of DBGDTRTX_EL0. It is a component of the Debug Communications Channel.

## Configuration

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

## Attributes

OSDTRTX_EL1 is a 64-bit register.

## Field descriptions

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
Return DTRTX without side-effect

#### Bits [63:32]

Reserved, RES0.

#### 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'.

## Accessing OSDTRTX_EL1

Arm deprecates reads and writes of OSDTRTX_EL1 when the OS Lock is unlocked.

Accesses to this register use the following encodings in the System register encoding space:

#### MRS <Xt>, OSDTRTX_EL1

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b10 | 0b000 | 0b0000 | 0b0011 | 0b010

if PSTATE.EL == EL0 then UNDEFINED; elsif Halted() && ConstrainUnpredictableBool(Unpredictable_IGNORETRAPINDEBUG) then X[t, 64] = OSDTRTX_EL1; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_FGT) && MDCR_EL3.TDCC == '1' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TDA == '1' then UNDEFINED; elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && MDCR_EL2.TDCC == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2.<TDE,TDA> != '00' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_FGT) && MDCR_EL3.TDCC == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif HaveEL(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = OSDTRTX_EL1; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_FGT) && MDCR_EL3.TDCC == '1' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TDA == '1' then UNDEFINED; elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_FGT) && MDCR_EL3.TDCC == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif HaveEL(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = OSDTRTX_EL1; elsif PSTATE.EL == EL3 then X[t, 64] = OSDTRTX_EL1;

#### MSR OSDTRTX_EL1, <Xt>

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b10 | 0b000 | 0b0000 | 0b0011 | 0b010

if PSTATE.EL == EL0 then UNDEFINED; elsif Halted() && ConstrainUnpredictableBool(Unpredictable_IGNORETRAPINDEBUG) then OSDTRTX_EL1 = X[t, 64]; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_FGT) && MDCR_EL3.TDCC == '1' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TDA == '1' then UNDEFINED; elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && MDCR_EL2.TDCC == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2.<TDE,TDA> != '00' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_FGT) && MDCR_EL3.TDCC == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif HaveEL(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else OSDTRTX_EL1 = X[t, 64]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_FGT) && MDCR_EL3.TDCC == '1' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TDA == '1' then UNDEFINED; elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_FGT) && MDCR_EL3.TDCC == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif HaveEL(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else OSDTRTX_EL1 = X[t, 64]; elsif PSTATE.EL == EL3 then OSDTRTX_EL1 = X[t, 64];

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

26/03/2024 09:49; 67c0ae5282a7629ba0ea0ba7267b43cd4f7939f6

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