The nostackframe modifier can be used to tell the compiler it should not generate a stack frame for this procedure or function. By default, a stack frame is always generated for each procedure or function, but the compiler will omit it if it can.
For asm routines (pure assembler) this directive can be used to omit generating a stack frame.
One should be extremely careful when using this modifier: most procedures or functions need a stack frame. Particularly for debugging they are needed.