11-4
MPC7400 RISC Microprocessor Users Manual
Special-Purpose Registers Used by the Performance Monitor
The user-level registers in Table 11-2 are read-only and are accessed with the
mfspr
instruction. Attempting to write to one of these registers in either supervisor or user mode
causes a program exception.
11.3.1 Performance Monitor Registers
This section describes the registers used by the performance monitor.
11.3.1.1 Monitor Mode Control Register 0 (MMCR0)
The monitor mode control register 0 (MMCR0), shown in Figure 11-1, is a 32-bit SPR
provided to specify events to be counted and recorded. MMCR0 can be written to only in
supervisor mode. User-level software can read the contents of MMCR0 by issuing an
mfspr
instruction to UMMCR0, described in Section 11.3.1.2, òUser Monitor Mode
Control Register 0 (UMMCR0).ó
Table 11-1. Performance Monitor SPRsSupervisor-Level
SPR Number
spr[5D9] || spr[0D4]
Register Name
944
0b11101 10000
Monitor mode control register 2MMCR2
951
0b11101 10111
Breakpoint address mask registerBAMR
952
0b11101 11000
Monitor mode control register 0MMCR0
953
0b11101 11001
Performance monitor counter register 1PMC1
954
0b11101 11010
Performance monitor counter register 2PMC2
955
0b11101 11011
Sampled instruction address registerSIAR
956
0b11101 11100
Monitor mode control register 1MMCR1
957
0b11101 11101
Performance monitor counter register 3PMC3
958
0b11101 11110
Performance monitor counter register 4PMC4
Table 11-2. Performance Monitor SPRsUser Level (Read Only)
SPR Number
spr[5D9] || spr[0D4]
Register Name
928
0b11101 00000
User monitor mode control register 2UMMCR2
935
0b11101 00111
User breakpoint address mask registerUBAMR
936
0b11101 01000
User monitor mode control register 0UMMCR0
937
0b11101 01001
User performance monitor counter register 1UPMC1
938
0b11101 01010
User performance monitor counter register 2UPMC2
939
0b11101 01011
User sampled instruction address registerUSIAR
940
0b11101 01100
User monitor mode control register 1UMMCR1
941
0b11101 01101
User performance monitor counter register 3UPMC3
942
0b11101 01110
User performance monitor counter register 4UPMC4