#3 LAHF bug

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

The LAHF instruction loads the low byte of FLAGS unchanged into AH. According to the Intel manual it should instead first perform a special bit mask operation of the value.

Discussion

  • Memphis
    Memphis
    2008-06-17

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    Do you have any references for this. As far as i know it is just loaded into the register AH.

     
  • Memphis
    Memphis
    2008-06-17

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    i also found this in the intel manual ... but beleave me ... when coding this, we had books for the 8086 where the bits 1 3 and 5 are simply undefined. In the intel reference ist now has changed to a define value. Whatever - i'll fix this.

    ciao

    Christian