The EDDFR characteristics are:
Provides top level information about the debug system.
Debuggers must use EDDEVARCH to determine the Debug architecture version.
For general information about the interpretation of the ID registers, see 'Principles of the ID scheme for fields in ID registers' in the Arm® Architecture Reference Manual, Armv8, for Armv8-A architecture profile.
It is IMPLEMENTATION DEFINED whether EDDFR is implemented in the Core power domain or in the Debug power domain.
EDDFR is a 64-bit register.
The EDDFR 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 |
RES0 | TraceFilt | UNKNOWN | |||||||||||||||||||||||||||||
CTX_CMPs | RES0 | WRPs | RES0 | BRPs | PMUVer | TraceVer | UNKNOWN | ||||||||||||||||||||||||
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 |
Reserved, RES0.
Armv8.4 Self-hosted Trace Extension version. The defined values of this field are:
TraceFilt | Meaning |
---|---|
0b0000 |
Armv8.4 Self-hosted Trace Extension is not implemented. |
0b0001 |
Armv8.4 Self-hosted Trace Extension is implemented. |
All other values are reserved.
Reserved, RES0.
Reserved, UNKNOWN.
Number of breakpoints that are context-aware, minus 1. These are the highest numbered breakpoints.
In an Armv8-A implementation that supports AArch64 state in at least one Exception level, this field returns the value of ID_AA64DFR0_EL1.CTX_CMPs.
Reserved, RES0.
Number of watchpoints, minus 1. The value of 0b0000 is reserved.
In an Armv8-A implementation that supports AArch64 state in at least one Exception level, this field returns the value of ID_AA64DFR0_EL1.WRPs.
Reserved, RES0.
Number of breakpoints, minus 1. The value of 0b0000 is reserved.
In an Armv8-A implementation that supports AArch64 state in at least one Exception level, this field returns the value of ID_AA64DFR0_EL1.BRPs.
Performance Monitors Extension version.
This field does not follow the standard ID scheme, but uses the Alternative ID scheme described in 'Alternative ID scheme used for the Performance Monitors Extension version' in the Arm® Architecture Reference Manual, Armv8, for Armv8-A architecture profile, section D10.1.4.
Defined values are:
PMUVer | Meaning |
---|---|
0b0000 |
Performance Monitors Extension not implemented. |
0b0001 |
Performance Monitors Extension implemented, PMUv3. |
0b0100 |
PMUv3 for Armv8.1. As 0b0001, and also includes support for:
|
0b0101 |
PMUv3 for Armv8.4. As 0b0100 and also includes support for the PMMIR register. |
0b0110 |
PMUv3 for Armv8.5. As 0b0101 and also includes support for: |
0b1111 |
IMPLEMENTATION DEFINED form of performance monitors supported, PMUv3 not supported. Arm does not recommend this value in new implementations. |
ARMv8.1-PMU implements the functionality added by the value 0b0100.
ARMv8.4-PMU implements the functionality added by the value 0b0101.
ARMv8.5-PMU implements the functionality added by the value 0b0110.
All other values are reserved.
From Armv8.1, the value 0b0001 is not permitted.
From Armv8.4, the value 0b0100 is not permitted.
From Armv8.5, the value 0b0101 is not permitted.
In an Armv8-A implementation that supports AArch64 state in at least one Exception level, this field returns the value of ID_AA64DFR0_EL1.PMUVer.
Trace support. Indicates whether System register interface to a PE trace unit is implemented. Defined values are:
TraceVer | Meaning |
---|---|
0b0000 |
PE trace unit System registers not implemented. |
0b0001 |
PE trace unit System registers implemented. |
All other values are reserved.
A value of 0b0000 only indicates that no System register interface to a PE trace unit is implemented. A PE trace unit might nevertheless be implemented without a System register interface.
In an Armv8-A implementation that supports AArch64 state in at least one Exception level, this field returns the value of ID_AA64DFR0_EL1.TraceVer.
Reserved, UNKNOWN.
Component | Offset | Instance | Range |
---|---|---|---|
Debug | 0xD28 | EDDFR | 31:0 |
This interface is accessible as follows:
Component | Offset | Instance | Range |
---|---|---|---|
Debug | 0xD2C | EDDFR | 63:32 |
This interface is accessible as follows:
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