Processor Hardware/Software Interface
EECS 113
Assignment 2
University of California, Irvine
Assigned: April, 21, 2024
Due: April, 30, 2024 by 11:59PM
1 8051 Microcontroller Programming using Edsim51
If you have not already installed Edsim51 simulator, follow these instructions:
http://www.edsim51.com/installationInstructions.html
To see a list of all assembly commands, visit the following link:
https://www.keil.com/support/man/docs/is51/is51_opcodes.htm
To see a list of all characters, visit the following link:
where each element is an 8-bit number, you are required to write a program
that computes the sum of products of the elements in each row, i.e. find (a*b)+(c*d) and store the result
in the memory. The matrix should be added in code memory starting from location 30H as strings
in ASCII format. To make the computations easier, the elements of the 2x2 matrix
a b
c d
should be
stored in a single array as follows: a,b,c,d. Use the following template to put the individual test cases
in your code memory:
ORG 0
SJMP MAIN
ORG 30H
N1: DB ”10,04,20,01” ;a=10, b=04, c=20, d=01
DB 0
ORG 50H
MAIN: ...
1
To run arithmetic operations on numbers in string format, you have to convert the strings to decimal
numbers. For instance, the {0x36H,0x34H,0x39H,0x30H} sequence represents the number 6490. Check
the ASCII table for full details on ASCII representation. Each character in this string (including the
commas) will be stored in an 8-bit memory location, so for the example given above, the code memory
starting address 30H will look as follows:
(30H)=0x31H, (31H)=0x30H, (32H)=0x2cH, (33H)=0x30H, (34H)=0x34H, (35H)=0x2cH,
(36H)=0x32H, (37H)=0x30H, (38H)=0x2cH, (39H)=0x30H, (3AH)=0x31H.
You can use the DPTR to point to data in your code memory. The steps that your program needs to
go through are:
1. Initialize the DPTR to N1 and initialize any registers that you might need.
2. loop over the digits one-by-one by increasing DPTR until you reach a comma to find the value of
the first element a and store it in the register R2.
3. go through another round of loading the digits one-by-one until you reach a comma to find the
second element b and store it in register R3.
4. multiply a and b and save the 16-bit output in locations 50H (MSB) 51H (LSB) in data memory.
5. repeat the previous process for c and d, and add the result from a*b and store it back in memory
locations 50H and 51H. Keep in mind that this addition operation should be computed on 16-bit
values, so you can use what you learned in Assignment 1!
You can use the comma and null characters, along with conditional jumps to determine if you have
reached the end of the ASCII representation of an element and jump to the next step in your program.
Store the 16-bit output result on location 50H(MSB) and 51H(LSB) on the data memory as regular
hexadecimal numbers. You do not need to convert the output to string! The input numbers are 8 bits
or less than 256.
Test your code for the following cases:
Case1: a=02, b=12, c=15, d=03
EXPECTED OUTPUT: 50H=00H , 51H=45H (2*12+15*3 = 69 which is 45H in hex system)
Case2: a=40, b=07, c=36, d=10
EXPECTED OUTPUT: 50H=02H, 51H=80H (40*07+36*10 = 640 which is 280H in hex system)
2 Bonus point (10%)
Save the output in decimal system and in ASCII format, i.e. convert each digit to ASCII representation
and save them on data memory, starting from 60H. The most significant digit should be stored in 60H.
You can assume the output is always less than 256 (8 bits).
Case1: a=02, b=12, c=15, d=03,
EXPECTED OUTPUT: (50H)=00H, (51H)=45H, (60H)=30H, (61H)=30H, (62H)=34H, (63H)=35H
(0045 in ASCII is 00003435H)
Case2: a=40, b=07, c=36, d=10
EXPECTED OUTPUT: (50H)=02H, (51H)=80H (60H)=30H, (61H)=32H, (62H)=38H, (63H)=30H
(0280 in ASCII is 00323830H)
2
3 Assignment Deliverable
- To facilitate the grading process, submit a .txt file for the code and a .pdf file for the report.
- Your code should be commented and easy to read.
- Your report should contain brief details on how the code works, plus the screenshots showing the final
memory and register values for each test case.
- Submit the assignment before the deadline through Canvas.

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