microcode
/ˈmaɪkrəʊkɒd/Definitions
1. noun
A set of very low-level instructions that a computer’s central processing unit executes directly, often stored in read-only memory.
“The computer’s processor uses microcode to execute complex instructions.”
2. noun
A specific set of low-level instructions for a particular operation or function.
“The microcode for the new graphics processing unit was optimized for gaming performance.”