Extending MIPS datapath to implement SLL and SRL

  • Thread starter izelkay
  • Start date
  • Tags
    Mips
In summary, the question is about extending the datapath to implement SLL and SRL. The proposed solution involves adding a mux next to the register file to select between Read data 1 and Read data 2. The Instruction[10:6] (shift amount) would also need to be branched off of Instruction[15:0] and fed into the ALU. However, it may also require another mux to select between Instruction[10:6] and Instruction[15:0] depending on the operation selected.
  • #1
izelkay
115
3

Homework Statement


Here's the datapath:
nM8IuyM.png


So this seems like a pretty common question but I can't seem to find any answers on how to extend the datapath to implement SLL and SRL.

The Attempt at a Solution



This is how I would think to do it but I'm not entirely sure:

It would need another mux right next to Read data 1 next to the register file. This mux would take Read data 1 (rs) and Read data 2 (rt) as inputs. It would select Read data 1 if we're not doing a shift operation, and it would select rt if we ARE doing a shift operation (since sll and srl use rt, not rs). This would then be fed into the ALU.

Next, we would need to branch Instruction[10:6] (the shift amount) off of Instruction[15:0], and Instruction[10:6] would then be fed into the other port of the ALU. Is this correct thinking?
 
Physics news on Phys.org
  • #2
It looks like I'd actually need to feed Instruction[10:6] and Instruction[15:0] into another Mux and have it select Instruction[10:6] when I want to shift, which will then be sent through the sign extender and into the ALU when ALUSrc is set to 1. Right? Anyone?
 

Related to Extending MIPS datapath to implement SLL and SRL

1. How do SLL and SRL differ from other instructions in the MIPS datapath?

SLL (Shift Left Logical) and SRL (Shift Right Logical) instructions are different from other instructions in the MIPS datapath because they perform bitwise shift operations instead of arithmetic or logical operations.

2. What is the purpose of extending the MIPS datapath to implement SLL and SRL?

The purpose of extending the MIPS datapath to implement SLL and SRL is to provide additional functionality for manipulating binary data. These instructions are commonly used in tasks such as data compression and encryption.

3. How are SLL and SRL instructions executed in the MIPS datapath?

SLL and SRL instructions are executed in the MIPS datapath by first fetching the instruction from memory, then decoding it to determine the source and destination registers, and finally performing the shift operation using the ALU and updating the destination register with the result.

4. Are there any limitations to implementing SLL and SRL in the MIPS datapath?

Yes, there are some limitations to implementing SLL and SRL in the MIPS datapath. These instructions can only shift by a maximum of 31 bits, and they do not support shifting by a variable amount. Additionally, the destination register must be specified, which limits the flexibility of these instructions.

5. How can I test the functionality of SLL and SRL in the extended MIPS datapath?

To test the functionality of SLL and SRL in the extended MIPS datapath, you can write a simple program that uses these instructions and simulate it using a MIPS emulator or simulator. You can also use a hardware debugger to step through the execution of the instructions and observe the changes in the registers and memory.

Similar threads

  • Engineering and Comp Sci Homework Help
Replies
7
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
3K
  • Engineering and Comp Sci Homework Help
Replies
10
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
7
Views
3K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
3K
  • Engineering and Comp Sci Homework Help
Replies
4
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
4
Views
2K
  • Programming and Computer Science
Replies
3
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
4
Views
4K
  • Engineering and Comp Sci Homework Help
Replies
2
Views
3K
Back
Top