EDDFR2

This is a collection of Intel®’ IA32® Software Developer's Manuals (URL of the day) and AMD' AMD64 Architecture Programmer's Manual together with the related specifications, application notes, white papers, and change logs. The collection aims to keep all available revisions. It was originally created by Michal Necasek, see OS/2 Museum.

If you have a public document, related to the IA32® specifications and missing from the collection, please mail it to me. The content of this URL and all sub-ULRs is available for convenient bulk download by rsync x86docs password "" (empty).

EDDFR2, External Debug Feature Register 2

Purpose

Configuration

Attributes

Field descriptions

Bits [63:28]

TRBE_EXC, bits [27:24]

This field either has the same value as ID_AA64DFR2_EL1.TRBE_EXC or reads as zero.

This field has an IMPLEMENTATION DEFINED value.

Access to this field is RO.

SPE_nVM, bits [23:20]

This field either has the same value as ID_AA64DFR2_EL1.SPE_nVM or reads as zero.

This field has an IMPLEMENTATION DEFINED value.

Access to this field is RO.

SPE_EXC, bits [19:16]

This field either has the same value as ID_AA64DFR2_EL1.SPE_EXC or reads as zero.

This field has an IMPLEMENTATION DEFINED value.

Access to this field is RO.

Bits [15:8]

BWE, bits [7:4]

Breakpoints and watchpoint enhancements.

The value of this field is an IMPLEMENTATION DEFINED choice of:

BWE	Meaning
0b0000	This field does not indicate whether DBGBCR<n>_EL1.MASK and address mismatch breakpoints are implemented.
0b0001	DBGBCR<n>_EL1.MASK and address mismatch breakpoints are implemented.
0b0010	As 0b0001, and address mismatch watchpoints are implemented.

All other values are reserved.

FEAT_BWE implements the functionality identified by the value 0b0001.

FEAT_BWE2 implements the functionality identified by the value 0b0010.

When this field is 0b0000, ID_AA64DFR1_EL1.ABLE might indicate the presence of support for DBGBCR<n>_EL1.MASK and address mismatch breakpoints.

From Armv9.5, the value 0b0001 is not permitted.

In an implementation that supports AArch64, this field has the same value as ID_AA64DFR2_EL1.BWE.

Access to this field is RO.

STEP, bits [3:0]

This field either has the same value as ID_AA64DFR2_EL1.STEP or reads as zero.

This field has an IMPLEMENTATION DEFINED value.

Access to this field is RO.

Accessing EDDFR2

EDDFR2 can be accessed through the external debug interface:

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
RES0				TRBE_EXC				SPE_nVM				SPE_EXC				RES0								BWE				STEP