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RDPID
Henk-Jan Lebbink edited this page Jun 4, 2026
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RDPID — Read Processor ID
| Opcode/ Instruction | Op/ En | 64/32-bit Mode | CPUID Feature Flag | Description |
| F3 0F C7 /7 RDPID r32 | R | N.E./V | RDPID | Read IA32_TSC_AUX into r32. |
| F3 0F C7 /7 RDPID r64 | R | V/N.E. | RDPID | Read IA32_TSC_AUX into r64. |
1
| Op/En | Operand 1 | Operand 2 | Operand 3 | Operand 4 |
| R | ModRM:r/m (w) | N/A | N/A | N/A |
Reads the value of the IA32_TSC_AUX MSR (address C0000103H) into the destination register. The value of CS.D and operand-size prefixes (66H and REX.W) do not affect the behavior of the RDPID instruction.
DEST ← IA32_TSC_AUXNone.
#UD If the LOCK prefix is used. If CPUID.07H.00H:ECX.RDPID[22] = 0.
Same exceptions as in protected mode.
Same exceptions as in protected mode.
Same exceptions as in protected mode.
Same exceptions as in protected mode.
1.ModRM.MOD = 011B required
Source: Intel® 64 and IA-32 Architectures Software Developer's Manual, Combined Volumes (Order Number 325462-091US, March 2026)
Generated: 7-6-2026