Volume 4: Base IA-32 Instruction Reference
4:333
RDPMC—Read Performance-Monitoring Counters
Description
Loads the contents of the N-bit performance-monitoring counter specified in the ECX
register into registers EDX:EAX. The EDX register is loaded with the high-order N-32
bits of the counter and the EAX register is loaded with the low-order 32 bits.
The RDPMC instruction allows application code running at a privilege level of 1, 2, or 3
to read the performance-monitoring counters if the PCE flag in the CR4 register is set
for IA-32 System Environment operation or in the Itanium System Environment if the
performance counters have been configured as user level counters. This instruction is
provided to allow performance monitoring by application code without incurring the
overhead of a call to an operating-system procedure.
The performance-monitoring counters are event counters that can be programmed to
count events such as the number of instructions decoded, number of interrupts
received, or number of cache loads.
The RDPMC instruction does not serialize instruction execution. That is, it does not
imply that all the events caused by the preceding instructions have been completed or
that events caused by subsequent instructions have not begun. If an exact event count
is desired, software must use a serializing instruction (such as the CPUID instruction)
before and/or after the execution of the RDPCM instruction.
The RDPMC instruction can execute in 16-bit addressing mode or virtual 8086 mode;
however, the full contents of the ECX register are used to determine the counter to
access and a full N-bit result is returned (the low-order 32 bits in the EAX register and
the high-order N-32 bits in the EDX register).
Operation
IF (ECX != Implemented Counters) THEN #GP(0)
IF (Itanium System Environment)
THEN
SECURED = PSR.sp || CR4.pce==0;
IF ((PSR.cpl ==0) || (PSR.cpl!=0 && ~PMC[ECX].pm && ~SECURED)))
THEN
EDX:EAX
PMD[ECX+4];
ELSE
#GP(0)
FI;
ELSE
IF ((CR4.PCE = 1 OR ((CR4.PCE = 0 ) AND (CPL=0)))
THEN
EDX:EAX
PMD[ECX+4];
ELSE (* CR4.PCE is 0 and CPL is 1, 2, or 3 *)
#GP(0)
FI;
Opcode
Instruction
Description
0F 33
RDPMC
Read performance-monitoring counter specified by ECX into
EDX:EAX
Summary of Contents for ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3
Page 1: ......
Page 11: ...x Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 13: ...1 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 33: ...1 22 Volume 1 Part 1 Introduction to the Intel Itanium Architecture ...
Page 57: ...1 46 Volume 1 Part 1 Execution Environment ...
Page 147: ...1 136 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 149: ...1 138 Volume 1 Part 2 About the Optimization Guide ...
Page 191: ...1 180 Volume 1 Part 2 Predication Control Flow and Instruction Stream ...
Page 230: ......
Page 248: ...236 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 250: ...2 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 264: ...2 16 Volume 2 Part 1 Intel Itanium System Environment ...
Page 380: ...2 132 Volume 2 Part 1 Interruptions ...
Page 398: ...2 150 Volume 2 Part 1 Register Stack Engine ...
Page 486: ...2 238 Volume 2 Part 1 IA 32 Interruption Vector Descriptions ...
Page 750: ...2 502 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 754: ...2 506 Volume 2 Part 2 About the System Programmer s Guide ...
Page 796: ...2 548 Volume 2 Part 2 Interruptions and Serialization ...
Page 808: ...2 560 Volume 2 Part 2 Context Management ...
Page 842: ...2 594 Volume 2 Part 2 Floating point System Software ...
Page 850: ...2 602 Volume 2 Part 2 IA 32 Application Support ...
Page 862: ...2 614 Volume 2 Part 2 External Interrupt Architecture ...
Page 870: ...2 622 Volume 2 Part 2 Performance Monitoring Support ...
Page 891: ......
Page 1099: ...3 200 Volume 3 Instruction Reference padd Interruptions Illegal Operation fault ...
Page 1295: ...3 396 Volume 3 Resource and Dependency Semantics ...
Page 1296: ......
Page 1302: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 1494: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Page 1647: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Page 1884: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Page 1885: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Page 1886: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 1898: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...