Sun Microelectronics
305
A. Debug and Diagnostics Support
A.5.1 Instruction Breakpoint
There is no hardware support for instruction breakpoint in UltraSPARC. The TA
(Trap Always) instruction can be used to set program breakpoints.
A.5.2 Data Watchpoint
Two 64-bit data watchpoint registers provide the means to monitor data accesses
during program execution. When virtual/physical data watchpoint is enabled,
the virtual/physical addresses of all data references are compared against the
content of the corresponding watchpoint register. If a match occurs, a
VA_/
PA_watchpoint
trap is signalled before the data reference instruction is completed.
The virtual address watchpoint trap has higher priority than the physical address
watchpoint trap.
Separate 8-bit byte masks allow watchpoints to be set for a range of addresses.
Zero bits in the byte mask causes the comparison to ignore the corresponding
byte(s) in the address. These watchpoint byte masks and the watchpoint enable
bits reside in the LSU_Control_Register. See Section A.6, “LSU_Control_Register,”
on page 306 for a complete description.
A.5.3 Virtual Address (VA) Data Watchpoint Register
Figure A-2
VA Data Watchpoint Register Format (ASI 58
16
, VA=38
16
)
Table A-1
ASIs Affected by Watchpoint Traps
ASI Type
ASI Range
D-MMU
Watchpoint if
Matching VA
Watchpoint if
Matching PA
Translating ASIs
04
16
..11
16
,
18
16
..19
16
,
24
16
..2C
16
,
70
16
..71
16
,
78
16
..79
16
,
80
16
..FF
16
On
Off
Y
N
Y
Y
Bypass ASIs
14
16
..15
16
,
1C
16
..1D
16
—
N
Y
Nontranslating ASIs
45
16
..6F
16
,
76
16
..77
16
,
7E
16
..7F
16
—
N
N
63
2
3
0
44 43
—
DB_VA
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