It's still the same division as always. Linux and other UNIXes on x86 and x86_64 generally use AT&T syntax. The rest of the x86 world uses Intel syntax. And

It's still the same division as always. Linux and other UNIXes on x86 and x86_64 generally use AT&T syntax. The rest of the x86 world uses Intel syntax. And of course *nix has always been a minority on x86. > I've coded in a dozen other assembly languages for various processors, but Intel chips seem to be the only ones with two different assembly language syntaxes, It's a historical quirk. Generally, today if there is a widely used and accepted assembler syntax targeting the architecture, UNIX porters would use that assembler's syntax. GAS accepts normal ARM style syntax, for example. But that's today. x86 is ancient. And so is UNIX on the x86. Going all the way back to the late 1970s, the 8086 was one of the first microprocessors that could host a decent UNIX environment. The rush was on as soon as the chip was released. (Most of the porting fervour would shift to the 68000 about 18 months later when that came out.) There was no established assembler aside from the one from Intel. MASM wouldn't be written for another couple years. UNIX at this point already had a full quasi-portable toolchain, which of course was familiar to the porters. And they planned to live in an all-UNIX world anyway. The only assembly anyone would ever write would, hopefully, be a dozen lines in the kernel. So they just adapted what they had and what worked. The old PDP-11 UNIX assembler, backwards syntax and prefixes and all. And here we are 40 years later.