ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Debug Registers Reference
BRP
type
bits a
Summary of breakpoint generation options
Table C10-12 shows which values are compared and which are not for each type of BRP. Table entries in
bold typewriter indicate an element of the comparison that is made. Reading across the Comparison
columns for a row of the table gives the comparison to be made. For example, for the Linked IVA mismatch
(0b001), the comparison is:
Not (Equals[IVA] AND Set[Byte lanes]) AND Match[State] AND Link[Linked Breakpoint]
Breakpoint generation is described by the BRPMatch() pseudocode function, see Breakpoints and Vector
Catches on page C3-28.
Description
Table C10-12 DBGBVR meaning bits summary
Comparison
IVA b Byte lanes c Context ID d State e Linked
000 IVA match Equals AND Set AND Match
001 Linked IVA match f Equals AND Set AND Match AND Link
010 Context ID g, h Equals AND Match
011 Linked Context ID g, i Equals AND Link
100 IVA mismatch h Not (Equals AND Set) AND Match
101 Linked IVA mismatch f, h Not (Equals AND Set) AND Match AND Link
11x Reserved - - - - -
a. The DBGBVR meaning field, DBGBCR[22:20].
b. Matching IVA[31:2] against DBGBVR[31:2]. If the breakpoint Address range mask bits [28:24] are set to a value other
than 0b00000, a masked comparison is used. See Breakpoint address range masking behavior, v7 Debug on page C3-9.
c. IVA byte lanes. DBGBCR[8:5] indicate the byte lanes to be compared, see Byte address selection behavior on IVA
match or mismatch on page C10-55.
d. Matching CONTEXTIDR[31:0] against DBGBVR[31:0].
e. Processor state comparison made, according to value of DBGBCR[15:14, 2:1], see Breakpoint Control Registers
(DBGBCR) on page C10-49.
f. The Context ID is compared against the value of the linked breakpoint and a breakpoint event is only generated when
both conditions match. If the linked breakpoint is not capable of Context ID comparison, or is not configured for Linked
Context ID match, the generation of Breakpoint debug events is UNPREDICTABLE.
g. DBGBCR[8:5] for this BRP must be programmed to 0b1111; otherwise the generation of Breakpoint debug events is
UNPREDICTABLE.
h. When Monitor debug-mode is selected, take care when programming DBGBCR[2:1], Privileged access control. See
Unpredictable behavior on Software debug events on page C3-24 for more information.
i. See Linked comparisons on page C10-59.
C10-58 Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. ARM DDI 0406B