notReallyFact

constants:  addi x31, x0, 4                 # conditional immediate that if i >= 4 go to true part
            addi x30, x0, 2                 # the 2' in 2'*rec_func(i-2)+1

addi x2, x0, 1600               // initialize the stack to 1600, x2= stackpointer
ecall x5, x0, 5                 // read the input to x5, the 5 signalling its an integer input
jal x1, rec_func                // main thread jump point (head to rec_func block)
ecall x0, x10, 2                // print the result
beq x0, x0, exit

rec_func:
    addi x2, x2, -8                 // make room in stack
    sd x1, 0(x2)                    // store pointer and result in stack
    bge x5, x31, true               // if i > 3, then go to true branch
    ld x1, 0(x2)
    addi x10, x0, 1                 // if i <= 3, then return 1
    addi x2, x2, 8                  // reset stack point
    jalr x0, 0(x1)                  // link back to register x1 (main jump point)

true:
    addi x5, x5, -2                 // compute i-2
    jal x1, rec_func                // call recursive func for i-2
    ld x1, 0(x2)                    // load the return address
    addi x2, x2, 8                  // reset stack point
    mul x10, x10, x30               // multiply by 2
    addi x10, x10, 1                // add 1
    jalr x0, 0(x1)                  // return

exit: