Question

Question: Right before your function f from Exercise 2.34 returns, what do we know about contents of registers \(t5, \)s3, \(ra, and \)sp? Keep in mind that we know what the entire function f looks like, but for function func, we only know its declaration.

Short answer

The register ‘$ra’ returns the address of the variable. There will be no change in the value of ‘$sp,’ ‘$s3’. The register ‘$t5’ contains some random values.

Step-by-step solution

MIPS language

The language MIPS was started by John L. Hennessy, the tenth president of Stanford University, who worked in the electrical engineering and computer science department. He is the co-founder of the MIPS computer systems now known as MIPS technologies. They developed one of the first commercial RISC microprocessors. Every processor performs a different type of operation like arithmetic, and these instructions can be easily expressed by the MIPS notation. Some of the operations performed by the processors are arithmetic, data transfer, logical, conditional, and unconditional branches.

Contents of the registers

The function from exercise 2.34 is as follows:

int f(int a, int b, int c, int d)

{

return func(func(a,b),c+d);

}

The above function calls another function “func” inside of it, bypassing the argument, and the return value is an integer type.

Here the register ‘$ra,’ which is m, means to return the address for the variable inwhich the function is called. The registers ‘$sp’ and ‘$s3’ will have the same values they contain when the function f is called. Register ‘$t5’ contains the random value. Because the function f is not modifying the ‘$t5’but the function “func“ has permission to change it, we cannot predict the values of the register “$t5,” and the function “func” is called inside the function “f.”

The “ra” in the MIPS instruction is an instruction that means to return the address.

The “sp” in the MIPS instruction is an instruction that means the top of the stack pointer.