In general, upper 4 bits of Machine Instruction are assigned to an OP(eration) code and lower 12-bits the Operand which points to a location of the memory. Here we look at "KTG" instruction in detail.

Machine Instruction: 1110 0000 0000 0000
Assembly Instruction: KTG
Description: Keyboard Buffer to G register

The sequence of operations to be performed within Fetch Cycle:

Subcycle	HDL	Note
T6
T7	G<-KB	Copy Keyboard Buffer to G