Cortex-A8 R2P2.pdf - ARM Information Center

DebugBits Field Function[31:29] - Reserved. RAZ, SBZP.Table 12-26 shows how the bit values correspond with the Watchpoint ControlRegisters functions.Table 12-26 Watchpoint Control Registers bit functions[28:24] Watchpointaddress maskWatchpoint address mask. This field is used to watch a range of addresses by masking lowerorder address bits out of the watchpoint comparison:b00000 = no maskb00001 = reservedb00010 = reservedb00011 = 0x00000007 mask for data addressb00100 = 0x0000000F mask for data addressb00101 = 0x0000001F mask for data address...b11111 = 0x7FFFFFFF mask for data address.Note• If WCR[28:24] is not set to b00000, then WCR[12:5] must be set to b11111111.Otherwise, the behavior is Unpredictable.• If WCR[28:24] is not set to b00000, then the corresponding WVR bits that are not beingincluded in the comparison Should-Be-Zero. Otherwise, the behavior is Unpredictable.• To watch for a write to any byte in an 8-byte aligned object of size 8 bytes, ARMrecommends that a debugger sets WCR[28:24] to b00111, and WCR[12:5] tob11111111. This is compatible with both ARMv7 debug compliant implementationsthat have an eight-bit WCR[12:5] and with those that have a four-bit WCR[8:5] byteaddress select field.[23:21] - Reserved. RAZ, SBZP.[20] E Enable linking bit:0 = linking disabled1 = linking enabled.When this bit is set to 1, this watchpoint is linked with the context ID holding BRP selectedby the linked BRP field.[19:16] Linked BRP Linked BRP number. The binary number encoded here indicates a context ID holding BRP tolink this WRP with. If this WRP is linked to a BRP that is not configured for linked context IDmatching, it is Unpredictable whether a watchpoint debug event is generated.12-44 Copyright © 2006-2008 ARM Limited. All rights reserved. ARM DDI 0344E