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

Each unit of the instruction is checked against the VCR and the BRPs. VCRMatch()
// and BRPMatch() might return UNKNOWN for units other than the first unit of the
// instruction, as in some cases the generation of Debug events is UNPREDICTABLE.
for W = 0 to length-1
vcr_match = VCRMatch(address, W == 0) || vcr_match;
// This code does not take into account the case where a mismatch breakpoint
// does not match the address of an instruction but another breakpoint or
// vector catch does match the instruction. In that situation, generation of
// the Debug event is UNPREDICTABLE.
for N = 0 to UInt(DBGDIDR.BRPs)
brp_match = BRPMatch(N, address, W == 0) || brp_match;
address = address + step;
Debug Events
// A suitable debug event occurs if there has been a BRP match or a VCR match. If
// both have occurred, just one debug event occurs, and its type is IMPLEMENTATION
// DEFINED.
if vcr_match || brp_match then
if !vcr_match then BreakpointDebugEvent();
elsif !brp_match then VectorCatchDebugEvent();
else IMPLEMENTATION_DEFINED either BreakpointDebugEvent() or VectorCatchDebugEvent();
return;
// BRPMatch()
// ==========
boolean BRPMatch(integer N, bits(32) address, boolean first)
assert N