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I did a double take when I saw the generated assembly reference %r8d. Apparently this is a register that was added with AMD64. I guess that's what I get for no

by wtracy 14y ago

I did a double take when I saw the generated assembly reference %r8d. Apparently this is a register that was added with AMD64. I guess that's what I get for not keeping up with x86 assembly over the last five years.

0x0 14y ago
That's not valid in standard 32bit x86 assembly, is it? So in fact this is actually x86_64 / amd64 assembly, almost a different architecture. Edit: It is not valid according to http://www.codeproject.com/Articles/45788/The-Real-Protected-Long-mode-assembly-tutorial-for http://www.codeproject.com/Articles/45788/The-Real-Protected... - so headlining with "x86" is misleading at best.
- technogeek00 14y ago
  Correct the %r8 - %r15 registers were added by the x86_64 architecture and are 64-bit in length just as the others are now. They are commonly used for passing arguments to functions.
- mjb 14y ago
  The memory semantics are standard x86, but you are right that the registers are from x86_64 (and 64 bit mode at that). I'll update the article to clarify that point.
wolf550e 14y ago
At what point do we just call x86_64 "x86"? Do you for example have any x86 hardware that doesn't support x86_64? If so, what is it and what is it used for? from http://en.wikipedia.org/wiki/X86-64 http://en.wikipedia.org/wiki/X86-64 >> The first AMD64-based processor, the Opteron, was released in April 2003. >> The first processor to implement Intel 64 was the multi-socket processor Xeon code-named Nocona in June 2004. >> Intel's official launch of Intel 64 (under the name EM64T at that time) in mainstream desktop processors was the N0 Stepping Prescott-2M. All 9xx, 8xx, 6xx, 5x9, 5x6, 5x1, 3x6, and 3x1 series CPUs have Intel 64 enabled, as do the Core 2 CPUs, as will future Intel CPUs for workstations or servers. Intel 64 is also present in the last members of the Celeron D line. >> The first Intel mobile processor implementing Intel 64 is the Merom version of the Core 2 processor, which was released on 27 July 2006.

by wtracy 14y ago

0x0 14y ago

That's not valid in standard 32bit x86 assembly, is it? So in fact this is actually x86_64 / amd64 assembly, almost a different architecture. Edit: It is not valid according to http://www.codeproject.com/Articles/45788/The-Real-Protected-Long-mode-assembly-tutorial-for http://www.codeproject.com/Articles/45788/The-Real-Protected... - so headlining with "x86" is misleading at best.

technogeek00 14y ago
Correct the %r8 - %r15 registers were added by the x86_64 architecture and are 64-bit in length just as the others are now. They are commonly used for passing arguments to functions.
mjb 14y ago
The memory semantics are standard x86, but you are right that the registers are from x86_64 (and 64 bit mode at that). I'll update the article to clarify that point.

wolf550e 14y ago

At what point do we just call x86_64 "x86"? Do you for example have any x86 hardware that doesn't support x86_64? If so, what is it and what is it used for? from http://en.wikipedia.org/wiki/X86-64 http://en.wikipedia.org/wiki/X86-64 >> The first AMD64-based processor, the Opteron, was released in April 2003. >> The first processor to implement Intel 64 was the multi-socket processor Xeon code-named Nocona in June 2004. >> Intel's official launch of Intel 64 (under the name EM64T at that time) in mainstream desktop processors was the N0 Stepping Prescott-2M. All 9xx, 8xx, 6xx, 5x9, 5x6, 5x1, 3x6, and 3x1 series CPUs have Intel 64 enabled, as do the Core 2 CPUs, as will future Intel CPUs for workstations or servers. Intel 64 is also present in the last members of the Celeron D line. >> The first Intel mobile processor implementing Intel 64 is the Merom version of the Core 2 processor, which was released on 27 July 2006.