diff options
| -rw-r--r-- | adirar111/y86/fib.ys | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/adirar111/y86/fib.ys b/adirar111/y86/fib.ys new file mode 100644 index 0000000..156c1ae --- /dev/null +++ b/adirar111/y86/fib.ys @@ -0,0 +1,56 @@ +# y86 implementation of +# def fibonacci(n): +# if n <= 1: +# return n +# return fibonacci(n-1) + fibonacci(n-2) + +.pos 0 +main: +irmovq stack, %rsp # initialize stack pointer +irmovq $13, %rdi # %rdi = n +call fib # fib(n) +halt + + +fib: +irmovq $2, %rsi +irmovq $1, %rdx +rrmovq %rdi, %rcx +rrmovq %rdi, %r8 + +subq %rsi, %rcx # %rcx = n-2 +subq %rdx, %r8 # %r8 = n-1 +jle base # goto base if n <= 1 + +recursed: +# save to stack +pushq %r8 # %r8 = n-1 + +# recurse +rrmovq %rcx, %rdi # %rdi = n-2 +call fib # fib(n-2) + +# restore from stack +popq %r8 # %r8 = n-1 + +# save to stack +pushq %rax # %rax = fib(n-2) + +# recurse +rrmovq %r8, %rdi # %rdi = n-1 +call fib # fib(n-1) + +# restore from stack +popq %r10 # r10 = fib(n-2) + +addq %r10, %rax # %rax = fib(n-2) + fib(n-1) +jmp end + +base: +rrmovq %rdi, %rax # return n + +end: +ret + +.pos 0x1000 +stack: |