Untitled

## fibonacci.S

    .text                          # code section 
    .global fibonacci_asm          # declar the sum_asm function as a  global function
    .type fibonacci_asm, @function # define sum_asm as a function 
fibonacci_asm:
    mv      a0, s0
    addi    sp, sp, -16          # allocate stack
    sw      ra, 0(sp) 
    sw      s0, 4(sp) 
    sw      s1, 8(sp)
    sw      s2,12(sp)
    jal     ra, fibonacci       # call fib(n)
    mv      a0, s0              # a0 = s0 
    li      a1, 0  # a1 = 0
    li      a2, 0  # a2 = 0 
    j       epilogue   
## write assembly code here.
## call fibonacci function and get return value.

fibonacci:
## fibonacci function
    blt     a0, s2, condition   # if a0 <  2 then condition
    addi    s0, a0, -1
    blt     s0, s2, condition   # if s0 <  2 then condition
    
    addi    sp, sp, -8        # PUSH stack
    sw      ra, 0(sp)           # save ret stack
    sw      a0, 4(sp)           # save n(a0) of f(n)
    
    addi    a0, a0, -1          # n-1 in a0
    jal     fibonacci           # call fib(n-1)
    
    lw      s0, 4(sp)           # restore n
    sw      a0, 4(sp)          # save fib(n-1)
    addi    a0, s0, -2          # n-2 in a0
    jal     fibonacci           # call fib(n-2)
    
    lw      s0, 4(sp)          # get fib(n-1)   
    add     a0, a0, s0          # a0 = fib(n-1) + fib(n-2)
    
    lw      ra, 0(sp)           # Get ret addr
    addi    sp, sp, 8          # POP Stack
condition:
    ret                         # jr ra

epilogue:
    lw      ra, 0(sp) 
    lw      s0, 4(sp) 
    lw      s1, 8(sp)
    lw      s2,12(sp)
    addi    sp, sp, 16          # allocate stack
    ret
    # Write your assembly code funtion here.
    # Please notice the rules of calling convention.
    .size fibonacci_asm, .-fibonacci_asm