Action name: OpSegmentThis command converts the immediate operand(s) type of the current instruction/data to segment base. The segment bases are usually displayed like this:
mov ax, seg dsegWhen you use this command, IDA deletes the manually entered operand.
If IDA cannot find a segment whose base is equal to the operand value, it simply displays it as hex number.
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.
See also Edit|Operand types submenu.