Chapter 6, Problem 47E

Explanation of Solution

Pseudocode:

The pseudocode to print the sum of four values is as follows:

  Set Counter to 0

  Set Sum to 0

  WHILE Counter < 4

        Read Number

        Add Number to Sum

        Set Counter to Counter + 1

  Write Sum

Explanation:

In the above pseudocode,

• First, read the four input values from the user.
• Then, use a “WHILE” loop to calculate the sum of four input values.
• Finally, write the sum on the screen.

Assembly-language program:

The assembly language program to write the sum of four input values is as follows:

Symbol	Mnemonics	Operand	Comment
	BR	Main	; Branch to the location Main
Sum:	.WORD	0X0000	; Set up the value of the Sum to 0
Counter:	.WORD	0X0000	; Set up the value of the Counter to 0
Limit:	.WORD	0X0004	; Set up the value of the Limit to 4
Number:	.BLOCK	2	; Set up a two byte block for Number
Main:	LDA	Sum,d	; Load the Sum value into the accumulator
	DECI	Number,d	; Read and store Number
	ADDA	Number,d	; Add the Number value with Accumulator
	STA	Sum,d	; Store the accumulator value into Sum
	LDA	Counter,d	; Load the Counter value into accumulator
	ADDA	1,i	; Increment the Number by 1
	STA	Counter,d	; Store the ...