1.Implement a new unary instruction in place of NOP0 called STKADD. It should replace the two topmost items on the stack with their sum. Set NZVC according to the results of the addition. Use the test...

1.Implement a new unary instruction in place of NOP0 called STKADD. It should replace the two topmost items on the stack with their sum. Set NZVC according to the results of the addition. Use the test program provided in the Pep/9 app to test the features of the new instruction.
2.
Implement a new nonunary instruction in place of NOP called XORA, which computes the bitwise exclusive OR operation with the operand and the accumulator, placing the result in the accumulator. Allow only direct addressing. Status bits NZ should be set according to the results of the operation, and VC should remain unchanged. Use the test program provided in

the Pep/9 app to test the features of the new instruction.