This is an overview of the flags in Linux's /proc/cpuinfo and with the flags returned by CPUID.
| fpu | Intel | x87 floating point unit on-chip | |
| vme | Intel | Virtual-mode Enhanchements. (CR4.VME, CR4.PVI). Software interrupt indirection, expansion of the TSS with the software, indirection bitmap, EFLAGS.VIF, EFLAGS.VIP | |
| de | Intel | Debugging Exnteions. I/O breakpoints (CR4.DE) | |
| cmpxchg8b | Intel | supports CMPXCHG8B instruction | not shown in /proc/cpuinfo |
| pse | Intel | Page-size Extensions. (4 megabyte pages) | |
| tsc | Intel | Time Stamp Counter. Supports RDTSC and RSTSCP instructions. | |
| msr | Intel | Model Specific Registers. Supports RDMSR and WRMSR instructions. | |
| pae | Intel | Physical Address Extension. support for physical addresses above 32-bits. Number of additional bits is implementation specific | |
| mce | Intel | Machine check exceptions. (CR4.MCE) | |
| cx8 | Intel | ||
| apic | Intel | Advanced Programmable Interrupt Controller exists and is enabled | |
| sep | Intel | ||
| mtrr | Intel | Memory-type Range Register | |
| pge | Intel | Page Global Extension. (CR4.PGE) | |
| mca | Intel | Machine check architecture. | |
| cmov | Intel | Conditional Move. supports the CMOV and FCMOV instructions. | |
| pat | Intel | Page attribute table. PCD, PWT and PATi are used to alter memory type. | |
| pse36 | Intel | Page-size extension. Supports 36-bit physical addresses. PDE[20:13] supplies physical address [39:32] | |
| pn | Intel | ||
| clflush | Intel | supports CLFLUSH instruction | |
| dts | Intel | ||
| acpi | Intel | ||
| mmx | Intel | supports MMX instructions. 128-bit Media and Scientific Programming | |
| fxsr | Intel | supports FXSAVE and FXRSTOR instructions. | |
| sse | Intel | supports SSE extensions | |
| sse2 | Intel | supports SSE2 extensions. 64-bit Media Programming | |
| ss | Intel | ||
| ht | Intel | supports Hyper-Threading Technology. This must be enabled in the BIOS to be seen by the OS. | |
| tm | Intel | ||
| ia64 | Intel | ||
| pbe | Intel | ||
| syscall | AMD | ||
| mp | AMD | ||
| nx | AMD | no-execute page protection | |
| fxsr_opt | AMD | FXSAVE and FXRSTOR instruction optimizations | |
| rdtscp | AMD> | supports RDTSCP instruction | |
| lm | AMD | Long mode | |
| 3dnowext | AMD | AMD extensions to 3DNow instructions | |
| 3dnow | AMD | supports 3DNow instructions | |
| recovery | Transmeta | ||
| longrun | Transmeta | ||
| lrti | Transmeta | ||
| cxmmx | Linux | ||
| k6_mtrr | Linux | ||
| cyrix_arr | Linux | ||
| centaur_mcr | Linux | ||
| constant_tsc | Linux | ||
| pni | Intel | ||
| monitor | Intel | ||
| ds_cpl | Intel | ||
| vmx | Intel | ||
| est | Intel | ||
| tm2 | Intel | ||
| cid | Intel | ||
| cx16 | Intel | ||
| xtpr | Intel | ||
| rng | VIA/Cyrix/Centaur | ||
| rng_en | VIA/Cyrix/Centaur | ||
| ace | VIA/Cyrix/Centaur | ||
| ace_en | VIA/Cyrix/Centaur | ||
| lahf_lm | AMD | suports LAHF and SAHF instructions in 64-bit mode | |
| cmp_legacy | AMD | Core multi-processing legacy mode | |
| svm | AMD | Secure Virtual Machine feature | |
| cr8legacy | AMD | ||
| ts | power/thermal | Temperature sensor | |
| fid | power/thermal | Frequncy ID control | |
| vid | power/thermal | Voltage ID control is supported | |
| ttp | power/thermal | THERMTRIP is suoprted | |
| tm | power/thermal | Hardware thermal control is supported | |
| stc | power/thermal | Software thermal control is supported |
Last Updated: Febuary 24, 2006