Debugging and Profiling Your Game - Game Coding Complete - page 820

'

Luckily, you don t have to worry about the stack pointer as long as you do all your

jumping around within one function. Local scopes are creations of the compiler; they
don

s a good thing, because setting the next state-
ment to a completely different function is sure to cause havoc with the stack. If you
want to skip the rest of the current function and keep it from executing, just right-
click on the last closing brace of the function and set the next statement to that point.
The stack frame will be kept intact.

' t actually have stack frames. That '

Assembly Level Debugging
Inevitably, you

' '

t have source
code or even symbols for every component of your application, so you should under-
stand a little about the assembly window. Here

ll get to debug through some assembly code. You won

' s the assembly for the SetTheIP()

function we just talked about. Let ' s look at the debug version of this code:

void SetTheIP()
{
00411A10 55

push ebp

00411A11 8B EC mov ebp,esp

00411A13 81 EC E8 08 00 00 sub esp,8E8h

00411A19 53 push ebx

00411A1A 56 push esi

00411A1B 57 push edi

00411A1C 8D BD 18 F7 FF FF lea edi,[ebp-8E8h]

00411A22 B9 3A 02 00 00 mov ecx,23Ah

00411A27 B8 CC CC CC CC mov eax,0CCCCCCCCh

00411A2C F3 AB rep stos dword ptr [edi]

char buffer[2048];
buffer[0] = 0;
00411A2E C6 85 F8 F7 FF FF 00 mov byte ptr [buffer],0

for (int a=0; a<128; ++a)
00411A35 C7 85 EC F7 FF FF 00 00 00 00 mov dword ptr [a],0

00411A3F EB 0F jmp SetTheIP+40h (411A50h)

00411A41 8B 85 EC F7 FF FF mov eax,dword ptr [a]

00411A47 83 C0 01 add eax,1

00411A4A 89 85 EC F7 FF FF mov dword ptr [a],eax

00411A50 81 BD EC F7 FF FF 80 00 00 00 cmp dword ptr [a],80h

00411A5A 7D 35 jge SetTheIP+81h (411A91h)

{

MyClass m(a);
00411A5C 8B 85 EC F7 FF FF mov eax,dword ptr [a]

00411A62 50 push eax