Timeline for What does the "x" in "x86" represent?
Current License: CC BY-SA 4.0
9 events
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| Apr 17, 2019 at 1:10 | comment | added | Peter Cordes | Semi-related: Why does "i586" refer to Pentium 1, and why does "i686" refer to Pentium Pro? for why modern named instead of numbered CPUs still fit the x86 wildcard pattern with only a small stretch. | |
| Apr 17, 2019 at 1:00 | comment | added | Peter Cordes |
@JeremyP: gcc doesn't have -march=x86. It has -march=i386. See godbolt.org/z/xg19XI shows gcc -m32's help for invalid -march=... values, which lists all it supports. If you run x86 gcc with the default -m64, it leaves out arches that only support 32-bit mode. gcc -m16 exists, but still requires 386+ because it mostly just assembles its usual machine code with .code16gcc so instructions with explicit operands get an operand-size and address-size prefix. Anyway, the critical point is that gcc -march never pretended to set the target mode, just ISA extensions within it.
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| Apr 17, 2019 at 0:54 | comment | added | Peter Cordes | The start of x86: Intel 8080 vs Intel 8086? goes into what it means to be an x86 (supporting a mode that's binary compatible with 8086). | |
| Apr 16, 2019 at 13:41 | comment | added | G. Tranter | Read the question. I find it's always best to answer the question, not what I think is the question behind the question. The "x" is a wildcard. If you read the whole question, you'd see that the author already understands the architecture part. | |
| Apr 16, 2019 at 9:34 | comment | added | kubanczyk | @JeremyP Exactly my thoughts. Even in the nineties, I don't remember anybody using x86 to mean 80286 or earlier. The gap was too large to put 16-bit systems in the same bag as 32-bit. When x86 appeared as a term I think everyone meant "80386+" by it. | |
| Apr 16, 2019 at 8:47 | comment | added | JeremyP |
@G.Tranter I agree up to a point. However, if you write "x86" people usually assume you mean compatible with the Intel 80386. i.e. capable of running in 32 bit protected mode. For example, if you compile a C program with gcc -march=x86 the code won't run on an 8086.
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| Apr 15, 2019 at 21:32 | comment | added | G. Tranter | This answer is so far the only answer that addresses the original question about what the "x" represents. | |
| Apr 15, 2019 at 17:10 | review | Low quality posts | |||
| Apr 15, 2019 at 17:16 | |||||
| Apr 15, 2019 at 16:53 | history | answered | Raffzahn | CC BY-SA 4.0 |