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MPC7400 RISC Microprocessor Users Manual
The MPC7400 Processor Register Set
2.1.2.4.1 Monitor Mode Control Register 0 (MMCR0)
The monitor mode control register 0 (MMCR0), shown in Figure 2-5, is a 32-bit SPR
provided to specify events to be counted and recorded. The MMCR0 can be accessed only
in supervisor mode. User-level software can read the contents of MMCR0 by issuing an
mfspr
instruction to UMMCR0, described in Section 2.1.2.4.2, òUser Monitor Mode
Control Register 0 (UMMCR0).ó
Figure 2-5. Monitor Mode Control Register 0 (MMCR0)
This register must be cleared at power-up. Reading this register does not change its
contents. Table 2-7 describes the Telds of MMCR0 register.
Table 2-7. MMCR0 Field Descriptions
Bits
Name
Description
0
FC
Freeze counters.
0 The PMCs are incremented (if permitted by other MMCR bits).
1 The PMCs are not incremented (performance monitor counting is disabled). The
processor sets this bit when an enabled condition or event occurs and
MMCR0[FCECE] = 1. Note that SIAR is not updated if performance monitor
counting is disabled.
1
FCS
Freeze counters in supervisor state.
0 The PMCs are incremented (if permitted by other MMCR bits).
1 The PMCs are not incremented if MSR[PR] = 0.
2
FCP
Freeze counters in problem state.
0 The PMCs are incremented (if permitted by other MMCR bits).
1 The PMCs are not incremented if MSR[PR] = 1.
3
FCM1
Freeze counters while mark = 1.
0 The PMCs are incremented (if permitted by other MMCR bits).
1 The PMCs are not incremented if MSR[PMM] = 1.
4
FCM0
Freeze counters while mark = 0.
0 The PMCs are incremented (if permitted by other MMCR bits).
1 The PMCs are not incremented if MSR[PMM] = 0.
5
PMXE
Performance monitor exception enable.
0 Performance monitor exceptions are disabled.
1 Performance monitor exceptions are enabled until a performance monitor interrupt
occurs, at which time MMCR0[PMXE] is cleared
Software can clear PMXE to prevent performance monitor interrupts. Software can set
PMXE and then poll it to determine whether an enabled condition or event occurred.
0
1
2
3
4
5
6
7
8
9 10
15 16 17 18 19
25 26
31
FCP
THRESHOLD
FCECE
PMXE
FCM0
PMC1SEL
FCS
PMC2SEL
FC
PMC1CE
FCM1
PMCjCE
TRIGGER
TBSEL
TBEE