| ??? 12/23/08 10:20 Read: times |
#161111 - Register Banks? Responding to: ???'s previous message |
Ahmed Lazreg said:
I want to ask about banked access to first 32 ram adresses. You mean the four banks of "registers", R0..R7 ? http://www.8052.com/tutmemor.phtml#Internal RAM http://www.8052.com/tutbregs.phtml#R Registers Since we can access these ram addr using their address directly, why does banked access exists? It is very common that computer architectures provide a number of different ways to access the same locations in their memories - these are known as Addressing Modes The 8051 actually has a rather limited set of Addressing Modes relative to other processors! In this particular case, the Bank Switching facility is very useful for things like interrupt handlers, where the handler can very simply & quickly switch to a different Bank without having to do a lot of work in saving & restoring individual registers... Also, accessing these locations via their "Rn" names is quicker than accessing them via their absolute addresses - but is limited to just these 32 locations. |
| Topic | Author | Date |
| What is banked access needed for ? | 01/01/70 00:00 | |
| Register Banks? | 01/01/70 00:00 | |
| 3 bits in single instruction byte | 01/01/70 00:00 | |
| and bank switching ? | 01/01/70 00:00 | |
| Overhead | 01/01/70 00:00 | |
Got it now | 01/01/70 00:00 |