Question

Assuming nine-bit 2’s complement representation, convert the decimal number -137 to binary, show the effect of the ROL operation on it with initial carry C=1, show the status bits and then convert the result back to decimal. Repeat with the ASR operation. Write the RTL specification of both operations shown here.

Answer 1

Answer:

Given that

-137 to 2's complement representation:

137 in 9-bit binary is ------->010001001

Inverting 0 to 1:

101110110

By Adding 1:

101110111

ROL operation with initial Carry C=1:

Rotating left with carry =1

1

0

1

1

1

0

1

1

1

<<-------------

1-- carry

0

1

1

1

0

1

1

1

1

Carry=1

ROL with Carry 1 is :011101111

ASR operation:

0

1

1

1

0

1

1

1

1

--------> rotating right

0

0

1

1

1

0

1

1

1

ASR with by rotating right is : 001110111