Hi guys,

It's been a while but I'm back on this list.

I'll add my two cents on this subject.  A disagree with the concept that
writing in C means one should only think in C.  That's a quick way to
create code bloat applications in the small single chippers.

Each compiler has a quirk or two and examining the code created with
various 'C Language' constructs that do the same thing but generate
different code leads to shorter, tighter applications.  Yes,  it results
in sometimes producing C applications that don't look as much like C but
more like structured assembler but consistency does end up making the
programs just a readable.

For example,  I was handed some hardware which had two LEDs connected to
two I/O pins.  Pulling the pins low turned on the LED.  But also
connected to the same pins were two buttons that pulled the pins low.
To read the button state meant turning off the port bits so the lines
went high.  Then reading the pins,  and then restoring the state of the
outputs to leave the LEDs on/off as before.

Added to the complexity is that the function had to return a bit set in
a different position from the physical bit position of the LED/Switch
input.  First crack with thinking in C produced horrendous code.    Only
by examining what the assembler code looked like and trying a few
different options was I able to create a very tight chunk of code that
prevented any LED flicker while testing the keys.

BTW,  The compiler was the TASKING 8051 Rev 6 and didn't do as nice a
job as BYTECRAFT MPC for quality of code.

Cheers,

John Dammeyer

Wireless CAN with the CANRF module now available.
http://www.autoartisans.com/products
Automation Artisans Inc.
Ph. 1 250 544 4950


> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Andy Kunz
> Sent: Thursday, February 06, 2003 2:59 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [PIC]: C Language V's Assembler
>
>
> >Any time when I write C code I think in C
> >And I do not care about what is really happening
> >Inside of pic and C generated asm is hard to read
> >All labels are numbers hard to fallow. When any person starts writing
>
> Well it isn't intended to be viewed by you, so complexity of
> reading is
> immaterial.  The fact is, good optimizers produce code that may not be
> anything at all like you would write.  I don't have a problem
> following
> Hitec's labels around - they are very straightforwardly
> created and make
> lots of sense.
>
> >to know more about almost every thing in detail. You
> >Started long time ago you learned every thing your case
> >Is different.
>
> I would say that most embedded programmers start in assembly
> and move to C
> as project complexity and size increases.  Therefore my
> situation is the
> common one, not the "different" one.
>
> Andy
>
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