DBGCLAIMCLR_EL1, Debug Claim Tag Clear register

The DBGCLAIMCLR_EL1 characteristics are:

Purpose

Used by software to read the values of the CLAIM tag bits, and to clear these bits to 0.

The architecture does not define any functionality for the CLAIM tag bits.

Note

CLAIM tags are typically used for communication between the debugger and target software.

Used in conjunction with the DBGCLAIMSET_EL1 register.

This register is part of the Debug registers functional group.

Configuration

AArch64 System register DBGCLAIMCLR_EL1 is architecturally mapped to AArch32 System register DBGCLAIMCLR.

AArch64 System register DBGCLAIMCLR_EL1 is architecturally mapped to External register DBGCLAIMCLR_EL1.

An implementation must include 8 CLAIM tag bits.

This register is in the Cold reset domain. See the CLAIM field description for the effect of a Cold reset on the value returned by this register. This register is not affected by a Warm reset.

Attributes

DBGCLAIMCLR_EL1 is a 32-bit register.

Field descriptions

The DBGCLAIMCLR_EL1 bit assignments are:

313029282726252423222120191817161514131211109876543210
000000000000000000000000CLAIM

Bits [31:8]

Reserved, RAZ/SBZ. Software can rely on these bits reading as zero, and must use a should-be-zero policy on writes. Implementations must ignore writes.

CLAIM, bits [7:0]

Read or clear CLAIM tag bits. Reading this field returns the current value of the CLAIM tag bits.

Writing a 1 to one of these bits clears the corresponding CLAIM tag bit to 0. This is an indirect write to the CLAIM tag bits. A single write operation can clear multiple CLAIM tag bits to 0.

Writing 0 to one of these bits has no effect.

A cold reset clears the CLAIM tag bits to 0.

Accessing the DBGCLAIMCLR_EL1

This register can be read using MRS with the following syntax:

MRS <Xt>, <systemreg>

This register can be written using MSR (register) with the following syntax:

MSR <systemreg>, <Xt>

This syntax uses the following encoding in the System instruction encoding space:

<systemreg> op0op1CRnCRmop2
DBGCLAIMCLR_EL11000001111001110

Accessibility

The register is accessible as follows:

Control Accessibility
E2HTGENSEL0EL1EL2EL3
xx0 - RW n/a RW
x01 - RWRWRW
x11 - n/a RWRW

This table applies to all instructions that can access this register.

Traps and enables

For a description of the prioritization of any generated exceptions, see section D1.13.2 (Synchronous exception prioritization) in the ARM® Architecture Reference Manual, ARMv8, for ARMv8-A architecture profile. Subject to the prioritization rules, the following traps and enables are applicable when accessing this register.

When EL2 is implemented and is using AArch64 and SCR_EL3.NS==1 :

When EL3 is implemented and is using AArch64 :




18/04/2017 17:00

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