You can enter any 'C' expression with constants. Long arithmetic will be used for calculations.

In these expressions, you can use all the names that you have created in your program.

Some IDA commands such as selecting a portion of file to output or specifying a segment to move need an anchor.

To drop the anchor, you can either use the Alt-L key or the Shift-<arrow> combination, which is more convenient. You can also drop the anchor with the mouse by simply clicking and dragging it.

After you've dropped the anchor, you can navigate freely using arrows, etc. Any command that uses the anchor, raises it.

The anchored range is displayed with another color.

When you exit from IDA, the anchor value is lost.

An identifier is a name which starts with a letter and contains only letters and digits. The list of allowed characters is specified in config file IDA.CFG. All names are case-sensitive.

Maximal length of a name is specified in the configuration file too:

        MAX_NAME_LENGTH=120     // Maximal length of new names

Default is 120.

Some assemblers have a shorter name length limit, beware!

IDA will warn you if you enter an illegal name.

You must enter a segment base value as a hexadecimal number or a segment name. IDA will warn you if you enter an invalid segment.

You may enter a segment register name too.

You should enter an address as a hexadecimal number or a location name. When you enter the address in the hexadecimal format, you can omit the segment part of the address and the current segment will be used. Addresses beyond the program limits are invalid.

Also, you can enter a location name with a displacement:

        name+5

And finally you can specify a relative address:

        +10             0x10 bytes further
        -5              5 bytes backwards

If the entered string cannot be recognized as a hexadecimal number or location name, IDA will try to interpret it as an expression using the current script interpreter. The default interpreter is IDC.

Special addresses: $ - current location (depends on the current assembler) Examples:

456 current segment, offset 0x456

5E current segment, offset 0x5E

3000:34 segment 0x3000, offset 0x34

ds:67 segment pointed by ds, offset 0x67

0:4000000 linear address

0x4000000 start a location with name 'start'

 In the text version of IDA, you can use the following keys:

 Enter          starts a new line
 Ctrl-Enter     finishes the input
 Esc            cancels the input
 F1             gives some help

                                        Shift-<arrow>  Select
 Ctrl-L         Search Again            Shift-Ins       Paste
 Ctrl-O         Indent Mode             Shift-Del       Cut
 Ctrl-T         Delete Word             Ctrl-Ins        Copy
 Ctrl-U         Undo                    Ctrl-Del        Clear
 Ctrl-Y         Delete Line             Ctrl-K B        Start Select
 Ctrl-Left      Word Left               Ctrl-K H        Hide Select
 Ctrl-Right     Word Right
 Ctrl-PgUp      Text Start              Ctrl-Q A        Replace
 Ctrl-PgDn      Text End                Ctrl-Q F        Search
                                        Ctrl-Q H        Delete Line Start
                                        Ctrl-Q Y        Delete Line End

Input containing only whitespaces is equal to an empty input.

Do not forget that you can also use the clipboard.