Shifting and Instructions

Part I. Create an eight$-$bit word and then perform three of the shifting operations on it$.$

$($For ease of reading, I suggest that the word be broken into two $4-$bit pieces separated by a blank space $($i$.$e$.$ xxxx xxxx$)$

The possible shifting operations include:

Logical Shift Right

Logical Shift Left

Rotate Right

Rotate Left

Arithmetic Shift Right

Arithmetic Shift Left

Each operation should be performed independently on the original $8-$bit word.

Part II

Evaluate a short algebraic expression using code with three$-$operand instructions. The expression should have a minimum of three operands and $2$ operators. Operands may be alpha or numeric.

You may only use registers A through F$,$ plus X and T$.$

Registers A through F may not be changed, i$.$e$.$ their values are fixed.

Register T may be used as a temporary register, and Register X must contain the final answer.

Show the postfix for the expression, and then use a stack to evaluate the expression.

As an example, consider X$=$A $+$B $+$ C $*$ D

The three$-$operand instructions would be:

ADD X$,$ A$,$ B

MUL T$,$ C$,$ D

ADD X$,$ X$,$ T

The Postfix would be AB$+$CD$*+$

The stack would be:

PUSH $/$ A onto the stack

PUSH $/$ B onto the stack

ADD $/$pop A & B$,$ add them, and push the answer back on the stack

PUSH $/$C

PUSH $/$ D

MUL $/$pop C & D$,$ multiply them, and push the answer back on the stack

ADD $/$ pop X & T$,$ add them, and push the answer back on the stack

POP $/$ X off the stack

It is important to note that operational hierarchy dictates that we first perform all arithmetic inside inner parentheses;

then inside outer parentheses;

then do multiplication and division operations before addition and subtraction operations.