EDDFR1 External Debug Feature Register 1 Debug 0xD48 EDDFR1 When IsCorePowered(), !DoubleLockStatus(), and (!IsZero(EDDFR1()) or !OSLockStatus()) RO When FEAT_DoPD is implemented and !IsCorePowered() ERROR IMPDEF Provides top-level information about the debug system in AArch64. Identification Registers EDDFR1 is a 64-bit register. ABL_CMPs 63 56 7:0 Number of breakpoints that support address linking, minus 1. All other values are reserved. The number of breakpoints that support address linking is never more than either the number of breakpoints or the number of watchpoints. In an implementation that supports AArch64, this field has the same value as ID_AA64DFR1_EL1.ABL_CMPs. 0x00..0x3F Number of breakpoints that support address linking minus 1. RO When FEAT_ABLE is implemented 63 56 63:56 Reserved, RES0. Otherwise DPFZS 55 52 55:52 This field either has the same value as ID_AA64DFR1_EL1.DPFZS or reads as zero. This field has an IMPLEMENTATION DEFINED value. RO EBEP 51 48 51:48 This field either has the same value as ID_AA64DFR1_EL1.EBEP or reads as zero. This field has an IMPLEMENTATION DEFINED value. RO ITE 47 44 47:44 This field either has the same value as ID_AA64DFR1_EL1.ITE or reads as zero. This field has an IMPLEMENTATION DEFINED value. RO ABLE 43 40 43:40 Address Breakpoint Linking Extension. All other values are reserved. FEAT_BWE implements the address range breakpoints and mismatch breakpoints part of the functionality identified by the value 0b0001. FEAT_ABLE implements the functionality identified by the value 0b0001. In an implementation that supports AArch64, this field has the same value as ID_AA64DFR1_EL1.ABLE. 0b0000 Address Breakpoint Linking Extension not implemented. 0b0001 Address Breakpoint Linking Extension implemented. RO PMICNTR 39 36 39:36 This field either has the same value as ID_AA64DFR1_EL1.PMICNTR or reads as zero. This field has an IMPLEMENTATION DEFINED value. RO SPMU 35 32 35:32 This field either has the same value as ID_AA64DFR1_EL1.SPMU or reads as zero. This field has an IMPLEMENTATION DEFINED value. RO CTX_CMPs 31 24 31:24 Context-aware breakpoints. All other values are reserved. The value of this field is never greater than EDDFR1.BRPs. In an implementation that supports AArch64, this field has the same value as ID_AA64DFR1_EL1.CTX_CMPs. 0x00 EDDFR.CTX_CMPs is the number of context-aware breakpoints, minus 1. 0x01..0x3F Number of context-aware breakpoints minus 1. RO WRPs 23 16 23:16 Watchpoints. All other values are reserved. In an implementation that supports AArch64, this field has the same value as ID_AA64DFR1_EL1.WRPs. 0x00 EDDFR.WRPs is the number of watchpoints, minus 1. 0x01..0x3F Number of watchpoints minus 1. BRPs 15 8 15:8 Breakpoints. All other values are reserved. In an implementation that supports AArch64, this field has the same value as ID_AA64DFR1_EL1.BRPs. 0x00 EDDFR.BRPs is the number of breakpoints, minus 1. 0x01..0x3F Number of breakpoints minus 1. SYSPMUID 7 0 7:0 This field either has the same value as ID_AA64DFR1_EL1.SYSPMUID or reads as zero. This field has an IMPLEMENTATION DEFINED value. RO 2026-03-26 20:27:25 2026-03_rel