Cheat Engine

[Fresco]

let's suppose you're in a shooter

your game runs and runs and when you fire the run run code calls the "decrease ammo" code ...

for whatever reasons you want to know who(address) called the decrease ammo code ...

...
in the code list doubleclick the decrease ammo code.
the debugger should pop at that instruction.
scroll down the code till you see a ret instruction ...
right click the instruction before ret and click "break and trace instructions" ... track only 4 instructions not 1000 ...
now shoot one bullet.
a new window(tracer) should appear with some code.
right click anywhere and choose "expand all" ; and now doubleclick the instruction after your ret ... the debugger(memory viewer) should now show that instruction ... scroll up one line ... there you should find your caller.

[Geri]

Also useful for finding the end of the function:

Right-click -> Select current function

And if you stop the game (manual debugging), then Shift + F8 (Execute till return).

Or you can set a manual breakpoint and set a hotkey for Debug-> Run.
If the breakpoint is hit, CE will show the return addresses from the stack in the bottom right corner. Double click on them to see the return point.

[Dark Byte]

That works too most of the time. (As long as EBP isn't messed with, and as the OP is the same guy from http://forum.cheatengine.org/viewtopic.php?t=548457 , you can assume that in his case, EBP is messed up)

[Jeffrey_]

pretty useful, thanks fresco