X86-64: Difference between revisions
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m Link directly to Setting up long mode |
http://developer.amd.com/resources/documentation-articles/developer-guides-manuals/ was not a valid link changed to correct one. |
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===How do I detect if the CPU is 64 bits ?=== |
===How do I detect if the CPU is 64 bits ?=== |
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After calling CPUID with EAX=0x80000001, all AMD64 compliant processors have the longmode-capable-bit turned on in the extended feature flags (bit 29) in EDX. There are also other bits required by long mode; you can check them out in the CPUID docs in the [http://support.amd.com/us/Processor_TechDocs/24594.pdf AMD general purpose instruction reference] (Link dead, the original author probably meant "AMD64 Architecture Programmer’s Manual Volume 3: General Purpose and System Instructions", found here: http://developer.amd.com/resources |
After calling CPUID with EAX=0x80000001, all AMD64 compliant processors have the longmode-capable-bit turned on in the extended feature flags (bit 29) in EDX. There are also other bits required by long mode; you can check them out in the CPUID docs in the [http://support.amd.com/us/Processor_TechDocs/24594.pdf AMD general purpose instruction reference] (Link dead, the original author probably meant "AMD64 Architecture Programmer’s Manual Volume 3: General Purpose and System Instructions", found here: http://developer.amd.com/resources/developer-guides-manuals/) |
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===How do I enable Long Mode ?=== |
===How do I enable Long Mode ?=== |
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