Arithmetic Expressions

The expression evaluator will accept numeric values in a decimal, hexadecimal, binary and octal notation. These are indicated thus:

nnnnnnY

Binary number nnnnnn.
nnnnnnO
Octal number nnnnnn.
nnnnnnQ
Alternative notation for octal number nnnnnn,
nnnnnnT
Decimal number nnnnnn.
nnnnnnH
Hexadecimal number nnnnnn.

The base suffix may be in upper or lower case.

The default base when a suffix is omitted is hexadecimal.

The following represent the same number, expressed in each of the permissible forms:

    31    31t
    1fh
    37o
    37q
    10001111y

Arithmetic expressions are of three types:

Absolute

An arithmetic expression that resolves to a numeric value.

Absolute expressions may be formed from numeric values using arithmetic binary and unary operators and in-built functions together with parentheses (), to influence evaluation order.

Boolean
Boolean expressions are ones that resolve to either a TRUE or FALSE value.

Boolean expression may be formed from arithmetic expressions using boolean binary and unary operators together with parentheses (), to influence evaluation order.

Boolean expressions me be used as absolute values in arithmetic expressions. Whereupon TRUE assumes the value 1 and FALSE 0.

Address
An arithmetic expression that resolves to one or two numeric values that represent a linear, physical, segment:offset or selector:offset address.

Address expressions are be formed from absolute expressions using addressing separators.

Note:

The expression evaluator allows arithmetic values to be expressed in hexadecimal. A potential conflict may occur where symbol names exist that begin with letters: a - f. For example, a linear address expressed as %fe1234 may be rejected with the message:

   Invalid expression

where a symbol f or fe is defined. To avoid this conflict prefix the hexadecimal numeric value with a zero, thus:

   %0fe1234

If the same error message persists then the address refers to either paged out or unallocated virtual memory.

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