![]() ![]() The following example of a naked function containing custom prolog and epilog sequences uses the _LOCAL_SIZE symbol in the prolog sequence: // the_local_size_symbol. For example: mov eax, _LOCAL_SIZE Immediate operand-Okay You must not change or redefine the value of this symbol. This means that the programs that you write should support a GUI, a Graphical User. _LOCAL_SIZE can be used only as an immediate operand it cannot be used in an expression. This is a book on how to write computer programs in Visual Prolog. Its value is the total number of bytes of all user-defined local variables and compiler-generated temporary variables. The compiler determines the value of _LOCAL_SIZE. This symbol is used to allocate space for local variables on the stack frame in custom prolog code. The compiler provides a symbol, _LOCAL_SIZE, for use in the inline assembler block of function prolog code. To access local variables, calculate an offset from ebp by subtracting the appropriate value from ebp. The base pointer ( ebp) points to the pushed value of ebp. The stack always grows down (from high to low memory addresses). The following is the corresponding epilog code: pop Restore registers ![]() After pushing the registers, you can place any other appropriate data on the stack. The localbytes variable represents the number of bytes needed on the stack for local variables, and the variable is a placeholder that represents the list of registers to be saved on the stack. Sub esp, localbytes Allocate space for locals This example shows the standard prolog code that might appear in a 32-bit function: push ebp Save ebp It is also useful to know how to use the _LOCAL_SIZE symbol. Before writing your own prolog and epilog code sequences, it is important to understand how the stack frame is laid out. ![]()
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