IBM powerpc 750gx Manuel D’Utilisation

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User’s Manual
IBM PowerPC 750GX and 750GL RISC Microprocessor
Performance Monitor and System Related Features
Page 354 of 377
gx_11.fm.(1.2)
March 27, 2006
Bits MMCR1[5:9] specify events associated with PMC4, as shown in Table 11-5
The PMC registers can be accessed with the mtspr and mfspr instructions using the following SPR 
numbers:
• PMC1 is SPR 953.
• PMC2 is SPR 954.
• PMC3 is SPR 957.
• PMC4 is SPR 958.
11.2.1.6 User Performance-Monitor Counter Registers (UPMC1–UPMC4)
The contents of the PMC1–PMC4 are reflected to UPMC1–UPMC4, which can be read by user-level soft-
ware. The UPMC registers can be read with the mfspr instructions using the following SPR numbers:
• UPMC1 is SPR 937.
• UPMC2 is SPR 938.
• UPMC3 is SPR 941.
• UPMC4 is SPR 942.
1 0000
Number of branches in the second speculative stream that resolve correctly.
1 0001
Number of cycles the BPU stalls due to LR or CR unresolved dependencies.
All others
Reserved. Might be used in a later revision.
Table 11-5. PMC4 Events—MMCR1[5:9] Select Encodings 
Encoding
Comments
00000
Register holds current value
00001
Number of processor cycles
00010
Number of completed instructions, not including folded branches
00011
Number of transitions from 0 to 1 of specified bits in the Time Base Lower (TBL) register. Bits are specified through 
RTCSELECT, MMCR0[7–8]. 00 = 31, 01 = 23, 10 = 19, 11 = 15 
00100
Number of instructions dispatched. 0, 1, or 2 per cycle
00101
Number of L2 castouts
00110
Number of cycles spent performing table searches for DTLB accesses.
00111
Reserved. Might be used in a later revision.
01000
Number of mispredicted branches. Reserved for future use.
01001
Reserved. Might be used in a later revision.
01010
Number of store conditional instructions completed with reservation intact
01011
Number of completed sync instructions
01100
Number of snoop request retries
01101
Number of completed integer operations 
01110
Number of cycles the branch processing unit (BPU) cannot process new branches due to having two unresolved 
branches
All others
Reserved. Might be used in a later revision.
Table 11-4. PMC3 Events—MMCR1[0:4] Select Encodings 
 (Page 2 of 2)
Encoding
Description