Question

How to separate 2000H of external RAM? Sent the high 4 bits to the low 4 bits of 2001H, and the low 4 bits are sent to the low 4 bits of 2002H. Clear the high 4 bits of 2001H and 2002H.

the answer in C program please

Answer 1

Write an assembly language program to add two 16 bit numbers by using:

• (a) 8 bit operation
• (b) 16 bit operation

(a) Addition of 16 bit numbers using 8 bit operation – It is a lengthy method and requires more memory as compared to 16 bit operation.

Algorithm –

1. Load the lower part of first number in B register
2. Load the lower part of second number in A (accumulator)
3. Add both the numbers and store
4. Load the higher part of first number in B register
5. Load the higher part of second number in A (accumulator)
6. Add both the numbers with carry from the lower bytes (if any) and store at the next location

Explanation –

1. LDA 2050 stores the value at 2050 in A (accumulator)
2. MOV B, A stores the value of A into B register
3. LDA 2052 stores the value at 2052 in A
4. ADD B add the contents of B and A and store in A
5. STA 3050 stores the result in memory location 3050
6. LDA 2051 stores the value at 2051 in A
7. MOV B, A stores the value of A into B register
8. LDA 2053 stores the value at 2053 in A
9. ADC B add the contents of B, A and carry from the lower bit addition and store in A
10. STA 3051 stores the result in memory location 3051
11. HLT stops execution