Convert x86 to Y-86

I'm trying to figure out to convert this x86 assembly code to Y86 form:

Given the c program:

 int sum(int x) { if (x == 0 || x ==1) { return 1; } else { return x + sum(x-1); } } 

The following x86-64 assembly code is generated:

sum: cmpl $1, %rdi ja .L8 movl $1, %eax ret .L8: pushq %rbx movl %edi, %ebx leal -1(%rdi), %edi call sum addl %ebx, %eax popq %rbx ret 

How can I convert this to Y86-64 assembly code that does the same thing?

Thank you!