MSR(Model-Specific Register) Additional, indirectly-accessible, registers containing control or status information about various aspects of the processor such as caches, performance counters, and the like. These registers, accessible via the RDMSR and WRMSR instructions, were added with the Pentium and later-model 486 processors. 8000001Ah - Pentium - FLOATING POINT - LAST NON-CONTROL OPCODE Size: 11 bits Access: Read SeeAlso: MSR(Model-Specific Register) Additional, indirectly-accessible, registers containing control or status information about various aspects of the processor such as caches, performance counters, and the like. These registers, accessible via the RDMSR and WRMSR instructions, were added with the Pentium and later-model 486 processors. 80000019h,MSR(Model-Specific Register) Additional, indirectly-accessible, registers containing control or status information about various aspects of the processor such as caches, performance counters, and the like. These registers, accessible via the RDMSR and WRMSR instructions, were added with the Pentium and later-model 486 processors. 8000001Bh,#R0057