For all the variables, the initial value are 0.

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1- Press the right button to reset everything.
2- Set the ALUOp to 1 (for 'inv' operation)
3- Set regfile_write_address to 3.
4- Set RegWrite to 1
5- Reset RegWrite back to 0

ALU output is inv of reg_file addr0 0000 0000 which is 1111 1111
Address 3 of the regfile is set to 0 1111 1111 (the 0 is ovf from alu)
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6- Change the regfile_read_address1 to 3
7- Change the ALUOp to 0x5 (for 'sll' operation)
8- Change the regfile_write_address to 1
9- Set RegWrite to 1
10- reset RegWrite back to 0

Input 1 to the ALU becomes regfile address 3 (1111 1111)
Output of ALU becomes sll of input 1 which becomes (1111 1110)
Writes 1111 1110 to address 1 of regfile
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11- Set the ALUSrc2 to 1
12- Set the value of alu_input2_vio(instr_i) to 0
13- Set the ALUOp to 0 (for 'add' operation)
14- Change the regfile_read_address1 to 3
15- Change the regfile_read_address2 to 1
16- Set MemWrite to 1
17- Reset MemWrite back to 0
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18- Change the regfile_read_address1 to 1
19- Set the value of alu_input2_vio(instr_i) to 1
20- Set the ALUSrc2 to 1
21- Set the ALUOp to 0 for 'add'
22- Set MemToReg to 1
23- Set regfile_write_address to 2
24- Set RegWrite to 1
25- Set RegWrite to 0
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