a (Assemble)

The a command assembles 32-bit x86 instruction mnemonics and puts the resulting instruction codes into memory.

a [Address]


Specifies the beginning of the block in memory where the resulting codes are put. For more information about the syntax, see Address and Address Range Syntax.



User mode, kernel mode


Live, crash dump



Additional Information

For more information about assembly debugging and related commands, see Debugging in Assembly Mode.


The a command does not support 64-bit instruction mnemonics. However, the a command is enabled regardless of whether you are debugging a 32-bit target or a 64-bit target. Because of the similarities between x86 and x64 instructions, you can sometimes use the a command successfully when debugging a 64-bit target.

If you do not specify an address, the assembly starts at the address that the current value of the instruction pointer specifies. To assemble a new instruction, type the desired mnemonic and press ENTER. To end assembly, press only ENTER.

Because the assembler searches for all of the symbols that are referred to in the code, this command might take time to complete. During this time, you cannot press CTRL+Cto end the a command.