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ur (Unassemble Real Mode BIOS)

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The ur command displays an assembly translation of the specified 16-bit real-mode code.

ur Range 
ur Address
ur

Parameters

Range
Specifies the memory range that contains the instructions to disassemble. For more information about the syntax, see Address and Address Range Syntax.

Address
Specifies the beginning of the memory range to disassemble. Eight instructions on an x86-based processor are unassembled. For more information about the syntax, see Address and Address Range Syntax.

Environment

Item Description
Modes User mode, kernel mode
Targets Live, crash dump
Platforms All

Additional Information

For more information about how to debug BIOS code, see Debugging BIOS Code.

Remarks

If you do not specify Range or Address, the disassembly begins at the current address and extends eight instructions on an x86-based processor.

If you are examining 16-bit real-mode code on an x86-based processor, both the ur command and the u (Unassemble) command give correct results.

However, if real-mode code exists in a location where the debugger is not expecting it (for example, a non-x86 computer that is running or emulating x86-based BIOS code from a plug-in card), you must use ur to correctly disassemble this code.

If you use ur on 32-bit or 64-bit code, the command tries to disassemble the code as if it were 16-bit code. This situation produces meaningless results.