19-194 Vol. 3B

PERFORMANCE-MONITORING EVENTS

ESCR Event Mask

Bit 
0: MMNP
1: MMNM
2: MMTP
3: MMTM

ESCR[24:9]

Branch not-taken predicted
Branch not-taken mispredicted
Branch taken predicted
Branch taken mispredicted

CCCR Select

05H

CCCR[15:13]

Event Specific 

Notes

P6: EMON_BR_INST_RETIRED

Can Support PEBS

No

mispred_branch_

retired 

This event represents the retirement of mispredicted branch 

instructions. 

ESCR restrictions

MSR_CRU_ESCR0
MSR_CRU_ESCR1

Counter numbers 

per ESCR

ESCR0: 12, 13, 16
ESCR1: 14, 15, 17

ESCR Event Select

03H

ESCR[31:25]

ESCR Event Mask

Bit 0: NBOGUS

ESCR[24:9]
The retired instruction is not bogus.

CCCR Select

04H

CCCR[15:13]

Can Support PEBS

No

x87_assist 

This event counts the retirement of x87 instructions that required 

special handling. 
Specifies one or more event mask bits to select the type of 

assistance.

ESCR restrictions

MSR_CRU_ESCR2
MSR_CRU_ESCR3

Counter numbers 

per ESCR

ESCR2: 12, 13, 16
ESCR3: 14, 15, 17

ESCR Event Select

03H

ESCR[31:25]

ESCR Event Mask

Bit 
0: FPSU
1: FPSO

ESCR[24:9]

Handle FP stack underflow.
Handle FP stack overflow.

2: POAO
3: POAU
4: PREA

Handle x87 output overflow.
Handle x87 output underflow.
Handle x87 input assist.

CCCR Select

05H

CCCR[15:13]

Can Support PEBS

No

Table 19-29.  Performance Monitoring Events For Intel NetBurst® Microarchitecture 

for At-Retirement Counting (Contd.)

Event Name

Event Parameters

 Parameter Value

Description