Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

                                             ◄Up► ◄Contents► ◄Index► ◄Back►
────────────────────────────────────────────────────────────────────────────
 
     See also: .IF, .UNTIL, .WHILE, Relational operators
 
     Operator      Meaning
 
     ==            Equal
     !=            Not equal
     >             Greater than
     >=            Greater than or equal to
     <             Less than
     <=            Less than or equal to
     &             Bit test (format: expression & bitnumber)
     !             Logical NOT
     &&            Logical AND
     ||            Logical OR
 
     CARRY?        Carry bit set
     OVERFLOW?     Overflow bit set
     PARITY?       Parity bit set
     SIGN?         Sign bit set
     ZERO?         Zero bit set
 
     The comparison run-time operators are used to make comparisons
     between variables, registers, and constants as the program is
     being executed. Use these operators to give conditions for
     conditional-control directives (.IF, .UNTIL, .WHILE). These
     operators can be combined with other run- time operators and
     parentheses to form complex conditions.
 
     The conditional-control directives (.IF, .UNTIL, .WHILE) can also
     check the state of processor flags. The CARRY?, OVERFLOW?,
     PARITY?, SIGN?, and ZERO? flags can be used directly in a C-style
     expression.
 
     For example:
 
       .IF   !PARITY? || ( AX == 0 ) ;Execute body of block if parity
             ∙                       ;flag is clear or if the AX
             ∙                       ;register is zero
             ∙
       .ENDIF
 
     Note: The expression is evaluated from left to right, so in this
           example, the state of the parity flag is checked before the
           AX comparison.
                                    -♦-