Fibonacci Number Calculator

            def fibonacci(n: int) -> int:
    previous, current = 0, 1
    for _ in range(n): previous, current = current, previous + current
    return previous
assert fibonacci(10) == 55
          

            #include <assert.h>
#include <stdint.h>
uint64_t fibonacci(uint64_t n){uint64_t p=0,q=1;while(n--){uint64_t t=p+q;p=q;q=t;}return p;}
int main(void){assert(fibonacci(10)==55);}
          

            #include <cassert>
#include <cstdint>
std::uint64_t fibonacci(std::uint64_t n){std::uint64_t p=0,q=1;while(n--){auto t=p+q;p=q;q=t;}return p;}
int main(){assert(fibonacci(10)==55);}
          

x86-64 NASM · System V ABI · Linux · integer arguments in rdi, rsi and rdx

            ; uint64_t fibonacci(uint64_t n)
global fibonacci
section .text
fibonacci:
    xor eax, eax
    mov rdx, 1
.loop:
    test rdi, rdi
    jz .done
    lea rcx, [rax+rdx]
    mov rax, rdx
    mov rdx, rcx
    dec rdi
    jmp .loop
.done:
    ret
          

            function result = fibonacci(n)
    n = round(n); a = 0; b = 1;
    for k = 1:n, next = a + b; a = b; b = next; end
    result = a;
end
          

            ClearAll[mwCalculate];
mwCalculate[n_Integer?NonNegative] := Fibonacci[n];