Question

Whenever possible, use the byte rotation scheme for the MOV instruction to generate an instruction needed to load the following constants into register r6. If it is not possible to use a MOV instruction, provide an alternative instruction.

a) MOV r6, #0x17400
b) MOV r6, #0x1980
c) ROT r6, #0x17400
d) ROT r6, #0x1980

Answer 1

The student's question involves using the MOV instruction for loading constants into a register. Direct MOV operations can be used for the examples given.

Step-by-step explanation:

The student's question is about using the MOV instruction and byte rotation scheme in assembly language to load constants into a register. When using the MOV instruction, it's important to remember that this instruction is used to place a value into a register without performing any logical or arithmetic operations. However, the ROT instruction typically refers to a bit rotation operation, which is different from MOV.

For the given constants:

• a) You can directly use MOV r6, #0x17400 to load the constant into r6.
• b) Similarly, use MOV r6, #0x1980 to load that constant into r6.
• c) There seems to be a typo as ROT is not the standard instruction to load a value. You may mean MOV or another operation altogether.
• d) Same as c), ROT is likely a typo. A typical rotation instruction might look like ROR or ROL and would require an additional operand specifying the number of bits to rotate.

If ROT is indeed a typo and a rotation is needed, instructions like ROR or ROL with the appropriate number of bits could be an alternative for specific scenarios.