#4 SAHF bug

open
nobody
Opcodes (4)
5
2007-07-22
2007-07-22
Arne Vidstrom
No

The SAHF instruction loads AH unchanged into the low byte of FLAGS. According to the Intel manual it should instead ignore some bits of AH.

Discussion

  • Memphis
    Memphis
    2008-06-17

    Logged In: YES
    user_id=990829
    Originator: NO

    Do you have any references for this. As of what i've found it just exchanges the low byte of flags with the content of AH. Why should some bits are ignored there. There maybe are some bits which are undefined in there state ... but those shouldn't be left out.

    ciao

    christian

     
  • Memphis
    Memphis
    2008-06-17

    Logged In: YES
    user_id=990829
    Originator: NO

    ok i've found it and will fix it to.