Compaq 21264 - Manual (Page 150)

5–8 Internal Processor Registers Alpha 21264/EV67 Hardware Reference Manual
Ibox IPRs
5.2.6 ProfileMe PC Register – PMPC
The ProfileMe PC register (PMPC) is a read-only register that contains the PC of the
last profiled instruction. Additional information is available in the I_STAT and
PCTR_CTL register descriptions.
Usage of PMPC in performance monitoring is described in Section 6.10.
Figure 5–11 shows the ProfileMe PC register.
Figure 5–11 ProfileMe PC Register
Table 5–4 describes the ProfileMe PC register fields.
5.2.7 Exception Address Register – EXC_ADDR
The exception address register (EXC_ADDR) is a read-only register that is updated by
hardware when it encounters an exception or interrupt.
EXC_ADDR[0] is set if the associated exception occurred in PALmode. The exception
actions are listed here:
• If the exception was a fault or a synchronous trap, EXC_ADDR contains the PC of
the instruction that triggered the fault or trap.
• If the exception was an interrupt, EXC_ADDR contains the PC of the next instruc-
tion that would have executed if the interrupt had not occurred.
Figure 5–12 shows the exception address register.
Figure 5–12 Exception Address Register
Table 5–4 ProfileMe PC Fields Description
Name Extent Type Description
PC[63:2] [63:2] RO Address of the profiled instruction
Reserved [1] RO Read as zero
PAL [0] RO Indicates that the PC field contains a physical-mode PALmode
address
63 2 1 0
PC[63:2]
PAL
LK99-0018A
63 2 1 0
PC[63:2]
PAL
LK99-0018A