Intel IXC1100 用户手册

Intel

®

 IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor

September 2006

DM

Order Number: 252480-006US

143

Counter overflow can be dealt with in the IRQ interrupt service routine as shown below:

As an example, assume the following values in CCNT, PMN0, PMN1 and PMNC:

; Configure the performance monitor with the following values:

;

EVTSEL.evtCount0 = 7, EVTSEL.evtCount1 = 0 instruction cache efficiency

;

INTEN.inten = 0x7 set all counters to trigger an interrupt on overflow

;

PMNC.C = 1  reset CCNT register

;

PMNC.P = 1  reset PMN0 and PMN1 registers

;

PMNC.E = 1  enable counting

MOV  R0,#0x700

MCR  P14,0,R0,C8,c1,0

; setup EVTSEL

MOV  R0,#0x7

MCR  P14,0,R0,C4,c1,0

; setup INTEN

MCR  P14,0,R0,C0,c1,0

; setup PMNC, reset counters & enable

; Counting begins

IRQ_INTERRUPT_SERVICE_ROUTINE:

; Assume that performance counting interrupts are the only IRQ in the system

MRC  P14,0,R1,C0,c1,0

; read the PMNC register

BIC  R2,R1,#1

  ; clear the enable bit, preserve other bits in PMNC

MCR  P14,0,R2,C0,c1,0

; disable counting

MRC  P14,0,R3,C1,c1,0

; read CCNT register

MRC  P14,0,R4,C0,c2,0

; read PMN0 register

MRC  P14,0,R5,C1,c2,0

; read PMN1 register

<process the results>

SUBS PC,R14,#4

; return from interrupt