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Volume 4: Base IA-32 Instruction Reference
4:335
RDTSC—Read Time-Stamp Counter
Description
Loads the current value of the processor’s time-stamp counter into the EDX:EAX
registers. The time-stamp counter is contained in a 64-bit MSR. The high-order 32 bits
of the MSR are loaded into the EDX register, and the low-order 32 bits are loaded into
the EAX register. The processor increments the time-stamp counter MSR every clock
cycle and resets it to 0 whenever the processor is reset.
In the IA-32 System Environment, the time stamp disable (TSD) flag in register CR4
restricts the use of the RDTSC instruction. When the TSD flag is clear, the RDTSC
instruction can be executed at any privilege level; when the flag is set, the instruction
can only be executed at privilege level 0. The time-stamp counter can also be read with
the RDMSR instruction.
In the Itanium System Environment, PSR.si and CR4.TSD restricts the use of the
RDTSC instruction. When PSR.si is clear and CR4.TSD is clear, the RDTSC instruction
can be executed at any privilege level; when PSR.si is set or CR4.TSD is set, the
instruction can only be executed at privilege level 0.
The RDTSC instruction is not serializing instruction. Thus, it does not necessarily wait
until all previous instructions have been executed before reading the counter. Similarly,
subsequent instructions may begin execution before the read operation is performed.
This instruction was introduced into the Intel architecture in the Pentium processor.
Operation
IF (IA-32 System Environement)
IF (CR4.TSD = 0) OR ((CR4.TSD = 1) AND (CPL=0))
THEN
EDX:EAX
TimeStampCounter;
ELSE (* CR4 is 1 and CPL is 1, 2, or 3 *)
#GP(0)
FI;
ELSE /*Itanium System Environment*/
SECURED = PSR.si || CR4.TSD;
IF (!SECURED) OR (SECURED AND (CPL=0))
THEN
EDX:EAX
TimeStampCounter;
ELSE (* CR4 is 1 and CPL is 1, 2, or 3 *)
#GP(0)
FI;
FI;
Flags Affected
None.
Opcode
Instruction
Description
0F 31
RDTSC
Read time-stamp counter into EDX:EAX
Содержание ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3
Страница 1: ......
Страница 11: ...x Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 12: ...1 1 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part I Application Architecture Guide ...
Страница 13: ...1 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 33: ...1 22 Volume 1 Part 1 Introduction to the Intel Itanium Architecture ...
Страница 57: ...1 46 Volume 1 Part 1 Execution Environment ...
Страница 147: ...1 136 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 149: ...1 138 Volume 1 Part 2 About the Optimization Guide ...
Страница 191: ...1 180 Volume 1 Part 2 Predication Control Flow and Instruction Stream ...
Страница 230: ......
Страница 248: ...236 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 249: ...2 1 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part I System Architecture Guide ...
Страница 250: ...2 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 264: ...2 16 Volume 2 Part 1 Intel Itanium System Environment ...
Страница 380: ...2 132 Volume 2 Part 1 Interruptions ...
Страница 398: ...2 150 Volume 2 Part 1 Register Stack Engine ...
Страница 486: ...2 238 Volume 2 Part 1 IA 32 Interruption Vector Descriptions ...
Страница 749: ...2 501 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part II System Programmer s Guide ...
Страница 750: ...2 502 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 754: ...2 506 Volume 2 Part 2 About the System Programmer s Guide ...
Страница 796: ...2 548 Volume 2 Part 2 Interruptions and Serialization ...
Страница 808: ...2 560 Volume 2 Part 2 Context Management ...
Страница 842: ...2 594 Volume 2 Part 2 Floating point System Software ...
Страница 850: ...2 602 Volume 2 Part 2 IA 32 Application Support ...
Страница 862: ...2 614 Volume 2 Part 2 External Interrupt Architecture ...
Страница 870: ...2 622 Volume 2 Part 2 Performance Monitoring Support ...
Страница 891: ......
Страница 941: ...3 42 Volume 3 Instruction Reference cmp illegal_operation_fault PR p1 0 PR p2 0 Interruptions Illegal Operation fault ...
Страница 1099: ...3 200 Volume 3 Instruction Reference padd Interruptions Illegal Operation fault ...
Страница 1191: ...3 292 Volume 3 Pseudo Code Functions Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1295: ...3 396 Volume 3 Resource and Dependency Semantics ...
Страница 1296: ......
Страница 1302: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1494: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Страница 1564: ...4 262 Volume 4 Base IA 32 Instruction Reference LES Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1565: ...Volume 4 Base IA 32 Instruction Reference 4 263 LFS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1568: ...4 266 Volume 4 Base IA 32 Instruction Reference LGS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1583: ...Volume 4 Base IA 32 Instruction Reference 4 281 LSS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1647: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Страница 1663: ...Volume 4 Base IA 32 Instruction Reference 4 361 SHL SHR Shift Instructions See entry for SAL SAR SHL SHR ...
Страница 1668: ...4 366 Volume 4 Base IA 32 Instruction Reference SIDT Store Interrupt Descriptor Table Register See entry for SGDT SIDT ...
Страница 1884: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Страница 1885: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Страница 1886: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1898: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...