CHAPTER 12. CONDITIONAL JUMPS CHAPTER 12. CONDITIONAL JUMPS

Chapter 12

Conditional jumps

12.1 Simple example

#include <stdio.h>

void f_signed (int a, int b)
{
if (a>b)
printf ("a>b\n");
if (a==b)
printf ("a==b\n");
if (a<b)
printf ("a<b\n");
};

void f_unsigned (unsigned int a, unsigned int b)
{
if (a>b)
printf ("a>b\n");
if (a==b)
printf ("a==b\n");
if (a<b)
printf ("a<b\n");
};

int main()
{
f_signed(1, 2);
f_unsigned(1, 2);
return 0;
};

12.1.1 x86

x86 + MSVC

Here is how thef_signed()function looks like:

Listing 12.1: Non-optimizing MSVC 2010

_a$ = 8
_b$ = 12
_f_signed PROC
push ebp
mov ebp, esp
mov eax, DWORD PTR _a$[ebp]
cmp eax, DWORD PTR _b$[ebp]
jle SHORT $LN3@f_signed
push OFFSET $SG737 ; 'a>b'
call _printf
add esp, 4