Memory Buffer Register (MBR)
The Memory Buffer Register (MBR), is used for storing the data that is to be written into or read out of the addressed location in memory.
If you look at your MIPS note, the load word instruction internally uses the MAR and MBR registers.
- MAR: Once the address is calculated, it is placed in the MAR to initiate the memory access.
- MBR: The data fetched from the memory location pointed to by the MAR is placed in the MBR.