Convert Lower-Case Letters to Upper Case in Assembly Code

How can we convert lower-case letters to upper case in assembly code?

Assume Register R0 contains an ASCII character. Write assembly code that converts any lower-case letters (a-z) to upper case (A-Z). For example, if Register R0 is initially ‘g’, convert it to ‘G’. Leave all other characters unchanged.

Assembly Code Explanation:

Here's an example of assembly code that converts a lower-case letter in Register R0 to upper case:

LOAD R1, 'a'   ; Load ASCII value of 'a' into R1

LOAD R2, 'A'   ; Load ASCII value of 'A' into R2

SUB R0, R0, R1 ; Subtract ASCII value of 'a' from the character in R0

ADD R0, R0, R2 ; Add ASCII value of 'A' to the result in R0

Assembly Code Breakdown:

In this code, we load the ASCII values of 'a' and 'A' into Registers R1 and R2, respectively. Then we subtract the ASCII value of 'a' from the character in Register R0. This effectively converts the lower-case letter to a value ranging from 0 to 25 (representing 'a' to 'z'). Finally, we add the ASCII value of 'A' to the result, resulting in the corresponding upper-case letter.