LOADALL

LOADALL is the common name for two different, undocumented machine instructions of Intel 80286 and Intel 80386 processors, which allow access to areas of the internal processor state that are normally outside of the IA-32 API scope, like descriptor cache registers. The LOADALL for 286 processors is encoded 0Fh 05h,[1] while the LOADALL for 386 processors is 0Fh 07h.[2]

Both variants – as the name implies – load all CPU internal registers in one operation. LOADALL had the unique ability to set up the visible part of the segment registers (selector) independently of their corresponding cached part, allowing the programmer to bring the CPU into states not otherwise allowed by the official programming model.

  1. ^ Cite error: The named reference Schulman_1990_Undocumented-DOS was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Gilluwe_1994 was invoked but never defined (see the help page).