x86 Opcode RDPMC

Opcode RDPMC

CPU: Pentium (tm) Pro (P6)
Type of Instruction: User

Instruction: RDPMC

Description:

IF ((CPL<>0) AND (CR4.PCE==0))
THEN { INT D (0) ; GENERAL PROTECTION FAULT }
ELSE { EDX:EAX <- PERFOMANCE_MONITORING_REGISTER[ECX] }
Note: Valid ECX values is 0,1.
Invalid ECX values call INT D(0)

Note: CR4.PSE = bit 8 of CR4

Note: Perfomance Monitoring Registers (PMR) are aliases to some Perfomance
Monitoring MSRs:

MSR 12h is Counter #0 (Read/Write) (Perfomance Monitoring Counter # 0)
bits Description
63..40 Reserved
39..0 Current counter value

MSR 13h is Counter #1 (Read/Write) (Perfomance Monitoring Counter # 1)
bits Description
63..40 Reserved
39..0 Current counter value

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COP & Times:

RDPMC 0FH 33H
P6: n/a