MOD OPERATOR for register in arm assembly

In ARM assembly language, the MOD operator is not directly available as a single instruction. However, you can perform modulus operations using a combination of instructions.

One common approach to calculate the modulus of a register by a constant is by using the UMULL (Unsigned Multiply Long) instruction, followed by an instruction to subtract the original value from the result. Here's an example:

UMULL   r0, r1, r2, #divisor
SUB     r0, r2, r0

In this example, r2 holds the dividend value, and divisor is the constant value you want to divide by. After executing these instructions, r0 will contain the remainder of the division operation.

If you want to perform modulus with a register instead of a constant, you can use the following approach:

UDIV    r0, r2, r3
MUL     r0, r0, r3
SUB     r0, r2, r0

In this example, r2 is the dividend register, and r3 is the divisor register. After executing these instructions, r0 will contain the remainder of the division operation.

Keep in mind that the exact instructions and syntax may vary depending on the specific ARM assembly dialect or processor architecture you are working with. It's always a good idea to consult the documentation or reference manual for your specific ARM processor to ensure accurate and efficient code execution.