Chapter 6, Problem 43E

Explanation of Solution

Executing the test plan for the algorithm:

The following program is used to read three values from the user and computes the sum of three values.

Program:

  BR     Main   ; Branch

sum:      .WORD     0x0000 ; Set up word with zero

num1:  .BLOCK  2      ; Set up a 2 byte block for num1

num2:  .BLOCK  2      ; Set up a 2 byte block for num2

num3:  .BLOCK  2      ; Set up a 2 byte block for num3

Main:  LDA     sum,d  ; Load 0 into the accumulator

       DECI    num1,d ; Read a value for num1

       DECI    num2,d ; Read a value for num2

       DECI    num3,d ; Read a value for num3

       ADDA    num3,d ; Add value of num3 with accumulator

       ADDA    num2,d ; Add value of num2 with accumulator

       ADDA    num1,d ; Add value of num1 with accumulator

  ...