CSSE232 : Computer Architecture I

Name: Date:

HW4

In the following assembly code fragment, registers x5 and x6 are initialized to N and zero respectively.
```
LOOP: beq  x5, x0, DONE
      addi x6, x6, 1
      addi x5, x5, -1
      jal x0, LOOP
DONE:
```
a. (2 points) What is the value in register x6 for when the code reaches the label DONE:?

b. (2 points) How many RISC-V instructions are executed?

c. (6 points) If the registers x5 and x6 correspond to variables i and a respectively, write the equivalent C code for the loop.

Consider the following C code fragment.
```
for (i=0; i<a; i++) {
  a = a + b;
}
```
a. (4 points) Assuming that the values of i, a, and b in registers x5, x6 and x7, translate the C code to RISC-V assembly. Use a minimum number of instructions.

b. (4 points) If the variables a and b are initialized to 10 and 1, what is the total number of RISC-V instructions executed?