Processor microcode information

Emulation of old PCs, PC hardware, or PC peripherals.

Re: Processor microcode information

Postby derSammler » 2017-10-27 @ 07:22

Very first sentence:
Since the 1970's, processor manufacturers have decoded the x86 instruction set architecture by internally decomposing x86 complex instruction set architecture (CISC) instructions into a sequence of simplifed reduced instruction set computing (RISC) micro-operations (uops), in order to achieve greater performance and effciency.

Err... no. There was no x86 until 1978 anyway (no one cared about x86 until 1981) and the first CPU that started to do this partly was the i80486 (1989). Doesn't seem worth reading if the first sentence of the introduction already doesn't get things right.
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Re: Processor microcode information

Postby vladstamate » 2017-10-27 @ 12:29

Well I agree that statement is broad (and it caught my eye too when I was reading it), but 8086 did have microcode. While you could not program it from the outside world, it was there. And that is '78 so theoretically still 70s.
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Re: Processor microcode information

Postby kazblox » 2017-10-27 @ 16:32

Still would love to delayer the 8086/8088 someday to see what is going on down there with the microcode. Simply decapping it won't help without going further.
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Re: Processor microcode information

Postby shiva2004 » 2017-10-27 @ 21:30

derSammler wrote:Very first sentence:
Since the 1970's, processor manufacturers have decoded the x86 instruction set architecture by internally decomposing x86 complex instruction set architecture (CISC) instructions into a sequence of simplifed reduced instruction set computing (RISC) micro-operations (uops), in order to achieve greater performance and effciency.

Err... no. There was no x86 until 1978 anyway (no one cared about x86 until 1981) and the first CPU that started to do this partly was the i80486 (1989). Doesn't seem worth reading if the first sentence of the introduction already doesn't get things right.


Exactly what I thought, no one with something interesting to say about micrprocessors will start with something like that, so goodbye.
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