[A83] Re: Point of making your own lcd_busy?


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[A83] Re: Point of making your own lcd_busy?



> What is the point of wasting 5 bytes of memory, in a direct LCD
> program, by writing your own lcd_busy subroutine, when it is already in
> ROM?  TI has documented it's own ROM call _lcd_busy, but if that's not
> good enough for us, we can call $07DE and it is exactly the same thing,
> cycle per cycle, byte per byte, as: push af, inc hl, dec hl, pop af,
> ret...
>
> Jeff

The point is mostly two things. One is that the lcd_busy routine is way
longer then needed, the other is that you can do usefull stuff in that
time instead of wasting it on just waiting.For a simple lcd update for example, you can do a few calculations for
memory pointers and some stuff like that in some of the wait periods, thus
saving a few cycles in a very common task.Not saying that its always needed. To just write an own lcd_busy, and
doing stuff like this in a program that doesn't need tight optimization
has ofcourse no point.
--Olle