alephnull on 07 December 2008
| MisterBlonde said: @alephnull The function paramaters are accessed via offsets from ebp. There aren't enough registers to store all the parameters for a particular callstack. They are pushed and popped onto the stack. All compilers do is compile c code into assembly instructions that are executed by the CPU. At run time they are non existent (unless you are talking about a JIT compiler). The assembly code will do the pushing and popping. Eip points to the next instruction to be executed. When a function makes a call it pushes it's return address onto the stack. There is no way during a synchronous call for the calling function to be running until the called function returns. That is what crashman was saying and that is what I was agreeing with. When the called function returns the calling function's return address is popped back into eip. google function prologue and epilogue for more details. |
If you don't think the compiler is involved what do you think happens when you add the keyword inline before a function definition? Would you agree with me that the compiler does not put an inline function's parameters on the call stack?
Try doing a backtrace on a piece of code compiled with -O3 in gcc. I think you will find that it inlines quite a bit. Particularly with the CBE and Xenon you have over a hundred registers per core, and if you don't think copious inlining is going on then... well, I dunno.
