u [range]
The u command disassembles bytes and displays the source statements, with addresses and byte values, that correspond to them. The display of disassembled code looks similar to a code listing for an assembled file. If you type the u command by itself, 20h bytes are disassembled at the first address after the one displayed by the previous u command.
range
Specifies the block of memory in which instructions are to be disassembled. If no range is given, the command disassembles the next 20h bytes.