The following tables and notes constitute an overview of the x86-based processors produced (most of which are still available in some form today). These tables are intended as a guide only, the most reliable way to determine CPU features (amongst newer CPUs at least) is by using CPUID.| wiki.osdev.org
This page or section is a work in progress and may thus be incomplete. Its content may be changed in the near future.| wiki.osdev.org
A Task State Segment (TSS) is a binary data structure specific to the IA-32 and x86-64 architectures. It holds information about a task. In Protected Mode the TSS is primarily suited for Hardware Task Switching, where each individual Task has its own TSS. For use in software multitasking, one or two are also generally used, as they allow for entering Ring 0 code after an interrupt. In Long Mode, the TSS has a separate structure and is used to change the Stack Pointer after an interrupt or per...| wiki.osdev.org
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This article discusses x86-64 CPUs (AMD64 and Intel's equivalent EM64T implementation). IA-64 (Itanium) is really a different beast and not addressed here.| wiki.osdev.org
Interrupts are signals from a device, such as a keyboard or a hard drive, to the CPU, telling it to immediately stop whatever it is currently doing and do something else. For example, a keyboard controller can send an interrupt when a character key was pressed. Then the OS can display the character on screen immediately, even if the CPU was doing something completely unrelated before, and return to what it was doing afterwards. When a specific interrupt arises, the CPU looks up an entry for t...| wiki.osdev.org
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