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548
March 2002 Release
1-800-255-7778
Virtex-II Pro™ Platform FPGA Documentation
R
The processor does not clear the DBSR status bits when IAC events fail to
occur. After an IAC event is recorded by a debugger, the corresponding status
bits should be cleared to prevent ambiguity when recording future debug
events.
IAC Address-Range Match
An IAC address-range match causes a debug event when the effective address
of the executing instruction falls within a range of addresses specified an IAC
n
register pair, as follows:
•
IA12 designates an address range specified by the IAC1 and IAC2 register
pair. To enable range comparisons using this register pair, software must:
-
Set DBCR0[IA12]
=
1.
-
Set either (or both) IA1
=
1 or IA2
=
1.
•
IA34 designates an address range specified by the IAC3 and IAC4 register
pair. To enable range comparisons using this register pair, software must:
-
Set DBCR0[IA34]
=
1.
-
Set either (or both) IA3
=
1 or IA4
=
1.
If IAC address-range comparison is enabled for a register pair, IAC exact-
address comparison is disabled for that register pair.
When an address-range match is detected, the IA
n
enable bits in DBCR0
determine which DBSR status bits are set to 1. For example, both DBSR[IA1,
IA2] are set to 1 if DBCR0[IA1, IA2]
=
1 when an IA12 address-range match is
detected. However, only DBSR[IA1] is set to 1 if DBCR0[IA1]
=
1 and
DBCR0[IA2]
=
0 when an IA12 address-range match is detected. The processor
does not clear the DBSR status bits when IAC events fail to occur. After an IAC
event is recorded by a debugger, the corresponding status bits should be
cleared to prevent ambiguity when recording future debug events.
Inclusive and Exclusive Ranges
The DBCR0[IA12X, IA34X] bits specify whether the corresponding address
ranges are inclusive or exclusive, as follows:
•
When clear, the corresponding range is inclusive.
If DBCR0[IA12X]=0, instruction addresses from (IAC1) to (IAC2)-1 fall
within the range. Addresses from 0 to (IAC1)-1 and (IAC2) to
0xFFFF_FFFF fall outside the range.
If DBCR0[IA34X]=0, instruction addresses from (IAC3) to (IAC4)-1 fall
within the range. Addresses from 0 to (IAC3)-1 and (IAC4) to
0xFFFF_FFFF fall outside the range.
•
When set, the corresponding range is exclusive.
Table 9-5:
IAC Exact-Address Match Resources
Event Enable Bit
(DBCR0)
IAC Range Disable
(DBCR0)
IAC Register Used
Event Status Bit
(DBSR)
IA1
IA12
=
0
IAC1
IA1
IA2
IAC2
IA2
IA3
IA34
=
0
IAC3
IA3
IA4
IAC4
IA4
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