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> as a x86 CPU is unable to execute 16-bit code when in 64-bit mode? This is still possible, though unsupported by Windows and Linux (the latter one never supp

> as a x86 CPU is unable to execute 16-bit code when in 64-bit mode? This is still possible, though unsupported by Windows and Linux (the latter one never supported 16 bit code).

monocasa 9y ago
32 bit x86 Linux supported 16 bit code. http://man7.org/linux/man-pages/man2/vm86.2.html http://man7.org/linux/man-pages/man2/vm86.2.html
- wolfgke 9y ago
  The vm86 syscall is for entering Virtual 8086 mode, which is indeed not supported in Long mode. This mode was for example used under Windows 9x for implementing the DOS box. But this is not what I was talking about. I am talking about 16 bit code in protected mode. This is/was used under Win16 and is supported in all 32 bit versions of Windows.
  - badsectoracula 9y ago
    Win16 can run in 64bit mode as long as it is 16bit protected mode code. WINE uses that to run Win3.1 apps in 64bit Linux. For example: http://i.imgur.com/KtgLeWu.png http://i.imgur.com/KtgLeWu.png (this is an old shot of mine and yes i used a XFCE theme to make it look like Win95 :-P)
    - wolfgke 9y ago
      > Win16 can run in 64bit mode as long as it is 16bit protected mode code. Not under Windows: https://news.ycombinator.com/item?id=14246521 https://news.ycombinator.com/item?id=14246521