Reply to post: Re: "I did not know that ARM actually prohibited adding instructions"

Talk about a calculated RISC: If you think you can do a better job than Arm at designing CPUs, now's your chance

Anonymous Coward
Anonymous Coward

Re: "I did not know that ARM actually prohibited adding instructions"

OK, one last try as it feels like you are deliberately either reading too much or too little into my comments, particularly given where this started as a critique of the results returned by the x86 CPUID instruction.

The CPUID instruction allows you to read information from the CPU that typically contains details about features the CPU supports. To use those features, a program (typically the OS i.e. https://github.com/torvalds/linux/blob/master/arch/x86/kernel/cpuid.c) will examine the CPU features and either enable support for that task via specific instructions or default to a general purpose function that performs the same task with the instructions found in the base ISA (albeit slower).

As an example, the FPU detection and setup code in Linux under linux/arch/x86/kernel/fpu/

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