Arithmetic Expansion
Arithmetic expansion is performed to determine the value of an expression. MDB commands
can be preceded by expressions that represent a start address or a repeat
count. Arithmetic expansion can also be performed to compute a numeric argument for
a dcmd. An expression can appear in an argument list enclosed in square
brackets preceded by a dollar sign ($[ expression ]). In this case, the expression
is replaced by its arithmetic value.
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-sized, short-sized, int-sized, 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-byte, two-byte, four-byte, 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-sized, short-sized, int-sized, or long-sized quantity at virtual address expression in the target's virtual address space
- */[1248]/expression
Value of a one-byte, two-byte, four-byte, 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
