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Guy Harris (talk | contribs) →Intro and definition: Umm, no. |
Guy Harris (talk | contribs) →Intro and definition: Comer's book speaks more of traditional microcoded processors than anything like modern x86 processors. |
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:::"It works like a microcontroller that treats MCU instructions as data and interprets it." is referring to the "In fully microcoded pre-P6 processors", ''not'' to the processors in which hardware reads macroinstructions and translates them to generated-on-the-fly micro-operations.
:::So I propose we ignore any edit that cannot distinguish between "microcode as simulator for an instruction set" (traditional microcode) and "micro-operations generated on the fly by the instruction decoder" (modern x86 and z/Architecture processors). [[User:Guy Harris|Guy Harris]] ([[User talk:Guy Harris|talk]]) 08:52, 20 July 2022 (UTC)
::::BTW, your other source's link informs me that I "have either reached a page that is unavailable for viewing or reached [my] viewing limit for this book", so I just bought it on Apple Books.
::::Section 8.9 "Microcoded Instructions" is discussing a traditional microcoded processor. Section 8.10 "Microcode Variations" says that "“On some CPUs, microcode implements the entire fetch-execute cycle — the microcode interprets the opcode, fetches operands, and performs the specified operation.", which is what I referred to as a "fully-microcoded processor", and which also implies that there are alternatives, such as "hardware directly fetches and decodes instructions and fetches some or all operands, and then jumps to microcode to implement the instruction".
::::Unfortunately, the book doesn't cover the way most general-purpose processors work these days; the word "superscalar" appears nowhere in the book, according to the Books app, and "out-of-order" only appears in one section with one paragraph. The stuff that processors from smartphones to supercomputers do is in sections 8.19 through 8.21, with very little detail. [[User:Guy Harris|Guy Harris]] ([[User talk:Guy Harris|talk]]) 09:19, 20 July 2022 (UTC)
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