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Re: amd64 running on Intel Celeron and Pentium?

On 4/17/22 4:52 AM, Cyril Brulebois wrote:
Elmar Stellnberger <estellnb@elstel.org> (2022-04-17):
I haven´t heard yet of a Pentium IV supporting amd64.
Likely it does not exist.

https://en.wikipedia.org/wiki/List_of_Intel_Pentium_4_processors seems
to disagree in general. Willamette seems to be old enough to be 32-bit
only though.

Interesting. The architecture is called amd64 quite rightfully in my opinion, as it was first introduced by release in 2003 of Opteron CPU (project Hammer) by AMD (Advanced Micro Devices):


However, Intel continued calling CPUs "Pentium 4" and since 2004 Intel CPUs in Wikipedia article Cyril mentions:


are said to be "Intel 64". That article does not mention the core CPU data width not address width. If my memory serves me, these were the same 32 bit CPUs with "physical address extension" just expanding the ability of CPU to handle larger address space. So, wikipedia article about Pentium CPU is at least wrong when it points "Intel 64" to Opteron (Amd64 or its x86_64 synonym). But somebody more knowledgeable in the history may correct me.

Incidentally, technical documentation on Intel website for these later pentiums is not acessible. I just tried to take a look at the technical documentation to prove for myself that I'm wrong above... but no information from primary source: Intel, just something on wikipedia (and we don't even know who takes responsibility for what wikipedia page says).


PS Of course, 32 bit CPU core can handle 64 bit data and addresses by using multiple operations for what 64 bit CPU will use a single one. Like pocket calculators which are using 1 to 4 bit addition register, yet happily processing really large numbers.


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