nanogui: Re: tcl/tk for nano-X
Subject:
Re: tcl/tk for nano-X
From:
Jordan Crouse ####@####.####
Date:
9 Feb 2001 15:08:36 -0000
Message-Id: <3A840923.CFEA9EC2@censoft.com>
Alex Holden wrote:
>
> On Fri, 9 Feb 2001, Amit Kulkarni wrote:
> > how do i check if my widget library is suitable for embedded use. Do i have
>
> There's no way to put any definite figures on it. It's a trade off between
> the cost of the Flash and RAM a particular piece of software takes up, and
> the amount of value it adds to the product. It's also depends on what
> alternatives are available with the features you need, plus if there is a
> licencing fee you have to factor the cost of that into the equation too.
Also there is a size issue. What will your widget set look like when it
is crammed onto a
200x200 window on a cell phone? And most importantly, was your widget
set written so it
can be used as a shared library?
> > I have currently compiled the sources on an intel desktop pc and have used
> > gcc to compile the sources.I have no idea about what the size will be using
> > a cross compiler.
>
> Probably not more than 2* in either direction. Roughly speaking, RISC
> architectures like ARM tend to need more instructions to do a particular
> thing then CISC architectures like x86.
We usually assume about 1.5 times bigger, but that depends on how good
the optimization gets.
>> What do i keep in mind before increasing on the size or cutting down
> > features?
>
> Just generally try to do things in a compact, efficient way. If you're
> faced with a choice between a fast, large way to do something and a slow,
> compact way to do it, it's generally best to do it the slow, compact way
> because at the moment at least, clock cycles are cheaper then Flash.
That is good advice. However, you also need to plan for the worst case
hardware. Most embedded devices
don't have floating point in hardware, so be careful if you are using
floating points, because they will
slow the machine down horribly (integer math anyone???) Also, look out
for RAM usage. Malloc is not your friend on a
small device. on't assume that you will
have a block device (disk, etc, etc...) available for temporary files.
So think big, but plan for a 150 MHZ processor with 8 MB of memory and a
black and white screen....
if you do, you will be ready for any hardware that people toss at you.
Jordan
