3.4. FIBONACCI NUMBERS
#include <stdio.h>
void fib (int a, int b, int limit)
{
int next=a+b;
printf ("%d\n", next);
if (next > limit)
return;
fib (b, next, limit);
};
int main()
{
printf ("0\n1\n1\n");
fib (1, 1, 20);
};
This is the output of non-optimizing MSVC, so thenextvariable is actually allocated in the local stack:
Listing 3.5: MSVC 2010 x86_next$ = -4 ; size = 4
_a$ = 8 ; size = 4
_b$ = 12 ; size = 4
_limit$ = 16 ; size = 4
_fib PROC
push ebp
mov ebp, esp
push ecx
mov eax, DWORD PTR _a$[ebp]
add eax, DWORD PTR _b$[ebp]
mov DWORD PTR _next$[ebp], eax
mov ecx, DWORD PTR _next$[ebp]
push ecx
push OFFSET $SG2751 ; '%d'
call DWORD PTR impprintf
add esp, 8
mov edx, DWORD PTR _next$[ebp]
cmp edx, DWORD PTR _limit$[ebp]
jle SHORT $LN1@fib
jmp SHORT $LN2@fib
$LN1@fib:
mov eax, DWORD PTR _limit$[ebp]
push eax
mov ecx, DWORD PTR _next$[ebp]
push ecx
mov edx, DWORD PTR _b$[ebp]
push edx
call _fib
add esp, 12
$LN2@fib:
mov esp, ebp
pop ebp
ret 0
_fib ENDP
_main PROC
push ebp
mov ebp, esp
push OFFSET $SG2753 ; "0\n1\n1\n"
call DWORD PTR impprintf
add esp, 4
push 20
push 1
push 1
call _fib
add esp, 12
xor eax, eax
pop ebp
ret 0