OpOffset

Description

Convert the current operand to an offset in the data segment. This command converts the immediate operand of the current instruction/data to an offset from the current data segment (DS). If the current DS value is unknown (or equal 0xFFFF) IDA will warn you - it will beep. In this case, you have to define DS register value for the current byte. The best way to do it is:

• jump to segment register change point (the Jump to segment register... command; action JumpSegmentRegister),

• change value of DS (the Change segment register value... command; action SetSegmentRegister)

• return (the Jump back command; action Return) or you can change default value of DS for the current segment (the Set default segment register value... command; action SetSegmentRegisterDefault).

If you want to delete offset definition, you can use this command again - it works as trigger. If the cursor is on the first operand (the cursor is before ',') then the first operand will be affected; otherwise, all other operands will be affected. If a range is selected using the anchor, IDA will perform 'en masse' conversion. It will convert immediate operands of all instructions in the selected range to offsets. However, IDA will ask you first the lower and upper limits of immediate operand value. If the operand value is >= lower limit and <= upper limit then the operand will be converted to offset, otherwise it will be left unmodified. To create offsets to structure members use the Offset (struct)... command (action OpStructOffset).