Question

Refer to the LMC program below. What the output of this program and write down what the data storage locations will hold after the instruction is complete in each iteration.

Mailbox
00
01
02
03
04
05

Contents
518
902
216
317
801
000


16 1 DAT
17 0 DAT
18 4 DAT

Use the following table to write vour answer.

at the beginning of program
after 1st iteration
after 2nd iteration
after 3rd iteration
after 4th iteration
after 5th iteration

Output
NA

Data Storage Locations
16 1
17 0
18 4

Answer 1

Based on the given LMC program and initial data storage contents, the output of this program is "NA" (not applicable) as there are no instructions to output any values.

Here is the table showing the data storage locations after each iteration:

| Iteration | Data Storage Locations |

|-----------|-----------------------|

| Beginning | 16: 1, 17: 0, 18: 4 |

| 1st | 16: 1, 17: 0, 18: 4 |

| 2nd | 16: 1, 17: 0, 18: 4 |

| 3rd | 16: 1, 17: 0, 18: 4 |

| 4th | 16: 1, 17: 0, 18: 4 |

| 5th | 16: 1, 17: 0, 18: 4 |

Since the program does not contain any instructions that modify the data storage locations, their values remain the same throughout the iterations.

Answer 2

The LMC program provided cannot be fully executed due to missing content for mailbox 02, preventing the completion of the subtraction operation and subsequent iterations. Therefore, no output or changes to data storage locations after the first iteration can be confidently stated.

Step-by-step explanation:

The question relates to the execution of a Little Man Computer (LMC) program and the tracking of changes to data storage locations after each iteration. The LMC is a simplified model of a computer, used for educational purposes to teach students about basic computer architecture and assembly language programming.

The LMC program provided consists of the following instructions:

• 518 - LDA 18 (Load the content of mailbox 18 into the accumulator)
• 902 - SUB 02 (Subtract the content of mailbox 02 from the accumulator)
• 216 - STA 16 (Store the content of the accumulator into mailbox 16)
• 317 - BRA 17 (Branch always to the instruction at mailbox 17, which should be 902)
• 801 - HLT (Halt the program)

Given the initial data storage location values:

• Mailbox 16 contains the value 1
• Mailbox 17 contains the value 0
• Mailbox 18 contains the value 4

The program flow ends after one iteration in which:

1. The value 4 (from mailbox 18) is loaded into the accumulator.
2. The value from mailbox 02 is subtracted, but we don't have the content of mailbox 02, so we are unable to complete this step and determine the output or the state of data storage locations. Without this information, further iterations cannot be computed.

Since we cannot continue without the missing instruction, no output or changes to the data storage locations can be provided with certainty.