Museum

Home

Lab Overview

Retrotechnology Articles

⇒ Online Manual

Media Vault

Software Library

Restoration Projects

Artifacts Sought

;



DEBUG "IF" Command...

IF <expr> <action-list>  [[-]Else <action-list>]

    An <action-list> is a list of one or more commands,
    separated by ";", and surrounded by square brackets [].

    The expression must have a boolean (logical) result, or
    an integer (integer32) result.

    An <expr> is a combination of program and debugger variables,
    constants, and one or more of the following operators:

        Addition and subtraction    +  -
        Multiplication              *
        Division                    DIV  /
        Modulus                     MOD  %
        Relational                   <     <=    >     >=    =     <>
                                                             ==    !=
                                    .LT.  .LE.  .GT.  .GE.  .EQ.  .NE.
        Logical and bitwise         OR   .OR.   !  ||  |
                                    AND  .AND.  &  &&
        Shift                       >>   <<

    You can mix FORTRAN, Pascal, and C operators from this list regardless
    of the language of the target program.  Note that the debugger
    performs division like FORTRAN, not like Pascal.  Hence, the
    quotient of two integers is always an integer.  If either operand
    is a floating-point number, the quotient is a floating-point number.

    The debugger evaluates expressions in a strict left-to-right order;
    no precedence rules apply.  Therefore, you must use parentheses to
    group elements that should be evaluated first.  For example,
    parentheses are required in the expression

        A <= (B*C)

    to cause the debugger to compare A with the product of B and C.

    Character string constants in expressions must be enclosed in single
    quotes, as in 'quotable'.  Use two adjacent single quotes to include
    a single quote in the string, as in 'ain''t'.

Typewritten Software • bear@typewritten.org • Edmonds, WA 98026