Gdb layout asm window showing raw instruction opcodes and operands

When I use layout asm command I see the following:

│0x4000f2 <_start+18>    mov    $0xffff0000,%eax 

When I use disas /r command I see the following:

0x00000000004000f2 <+18>:    b8 00 00 ff ff  mov    $0xffff0000,%eax

That is, in the latter case, I can also see the opcode b8 and the operand.

How should I adjust the command layout asm or what command should I run additionally to see the raw instructions in the asm window too? Thank you.