Arithmetic Expansion

Arithmetic expansion is performed when an MDB command is preceded by an optional expression representing a start address, or a start address and a repeat count. Arithmetic expansion can also be performed to compute a numerical argument for a dcmd. An arithmetic expression can appear in an argument list enclosed in square brackets preceded by a dollar sign ($[ expression ]), and will be replaced by the value of the expression.

Expressions can contain any of the following special words:

integer

The specified integer value. Integer values can be prefixed with 0i or 0I to indicate binary values, 0o or 0O to indicate octal values, 0t or 0T to indicate decimal values, and 0x or 0X to indicate hexadecimal values (the default).

0[tT][0-9]+.[0-9]+

The specified decimal floating point value, converted to its IEEE double-precision floating point representation

'cccccccc'

The integer value computed by converting each character to a byte equal to its ASCII value. Up to eight characters can be specified in a character constant. Characters are packed into the integer in reverse order (right-to-left), beginning at the least significant byte.

<identifier

The value of the variable named by identifier

identifier

The value of the symbol named by identifier

(expression)

The value of expression

.

The value of dot

&

The most recent value of dot used to execute a dcmd

+

The value of dot incremented by the current increment

^

The value of dot decremented by the current increment

The increment is a global variable that stores the total bytes read by the last formatting dcmd. For more information on the increment, refer to the discussion of "Formatting dcmds".

Unary Operators

Unary operators are right associative and have higher precedence than binary operators. The unary operators are:

#expression

Logical negation

~expression

Bitwise complement

-expression

Integer negation

%expression

Value of a pointer-sized quantity at the object file location corresponding to virtual address expression in the target's virtual address space

%/[csil]/expression

Value of a char-, short-, int-, or long-sized quantity at the object file location corresponding to virtual address expression in the target's virtual address space

%/[1248]/expression

Value of a one-, two-, four-, or eight-byte quantity at the object file location corresponding to virtual address expression in the target's virtual address space

*expression

Value of a pointer-sized quantity at virtual address expression in the target's virtual address space

*/[csil]/expression

Value of a char-, short-, int-, or long-sized quantity at virtual address expression in the target's virtual address space

*/[1248]/expression

Value of a one-, two-, four-, or eight-byte quantity at virtual address expression in the target's virtual address space

Binary Operators

Binary operators are left associative and have lower precedence than unary operators. The binary operators, in order of precedence from highest to lowest, are:

*

Integer multiplication

%

Integer division

#

Left-hand side rounded up to next multiple of right-hand side

+

Integer addition

-

Integer subtraction

<<

Bitwise shift left

>>

Bitwise shift right

==

Logical equality

!=

Logical inequality

&

Bitwise AND

^

Bitwise exclusive OR

|

Bitwise inclusive OR