Pic, c programing

[Don Taylor]

cbarn24050@aol.com (CBarn24050) writes:

Your statements that a C compiler for the PIC takes 5x the code or
10-100x the time of an AVR one is just plain silly and ill-informed.

That isn't what I said.

Someone, several messages earlier in this thread made the comment that
using a C compiler would result in the 5x and 10-100x over assembly.
No particular processor family was mentioned. I believe that was where
this statement originated.

I was skeptical asked for plausible examples of this. No such examples
showed up but I did get email from one person suggesting that I try
to completely re-implement a project of his with my using C and see what
the comparison was. I haven't decided whether to try that or not.

. The CodeVision compiler I
used took more code space for floating point than my Hitech PICC
compiler on the PIC 16 series. I was not that impressed.

Thats very suprising, I too would not be impressed.

Maybe I'm just using PIC and C for smaller projects, but I wouldn't
think of using floating point math on one of these to begin with

 

[David L. Jones]

dont@agora.rdrop.com (Don Taylor) wrote in message news:<9o6dnTgVaYBlztrcRVn-qw@scnresearch.com>...

cbarn24050@aol.com (CBarn24050) writes:
Your statements that a C compiler for the PIC takes 5x the code or
10-100x the time of an AVR one is just plain silly and ill-informed.

That isn't what I said.

Someone, several messages earlier in this thread made the comment that
using a C compiler would result in the 5x and 10-100x over assembly.
No particular processor family was mentioned. I believe that was where
this statement originated.

I was skeptical asked for plausible examples of this. No such examples
showed up but I did get email from one person suggesting that I try
to completely re-implement a project of his with my using C and see what
the comparison was. I haven't decided whether to try that or not.

. The CodeVision compiler I
used took more code space for floating point than my Hitech PICC
compiler on the PIC 16 series. I was not that impressed.

Thats very suprising, I too would not be impressed.

Maybe I'm just using PIC and C for smaller projects, but I wouldn't
think of using floating point math on one of these to begin with

No problem with floating point on small 8bit micros, common as mud in
fact. Useful floating point work can be done in less than 2K words of
memory.

Dave

 

[David L. Jones]

cbarn24050@aol.com (CBarn24050) wrote in message news:<20040914053024.11452.00003381@mb-m23.aol.com>...

Your statements that a C compiler for the PIC takes 5x the code or
10-100x the time of an AVR one is just plain silly and ill-informed.

That isn't what I said.

Yes you did!, and I quote:
"Just compare you c program running on a pic then run it on an avr. It is true
that the 18 series make a much better job. If you can put up with using 5 times
as much memory and a speed penalty of 10 to100 times slower then c is ok on
these chips."

Pretty hard to misinterpret that!

Dave

 

[CBarn24050]

Yes you did!, and I quote:
"Just compare you c program running on a pic then run it on an avr. It is
true
that the 18 series make a much better job. If you can put up with using 5
times
as much memory and a speed penalty of 10 to100 times slower then c is ok on
these chips."

Pretty hard to misinterpret that!

Dave

sorry dave but you missed the earlier bit, it's a comparison with C and asm on
the pic.

 

[David L. Jones]

cbarn24050@aol.com (CBarn24050) wrote in message news:<20040915155405.29642.00000648@mb-m12.aol.com>...

Yes you did!, and I quote:
"Just compare you c program running on a pic then run it on an avr. It is
true
that the 18 series make a much better job. If you can put up with using 5
times
as much memory and a speed penalty of 10 to100 times slower then c is ok on
these chips."

Pretty hard to misinterpret that!

Dave

sorry dave but you missed the earlier bit, it's a comparison with C and asm on
the pic.

Even so, your figures are still *way* off the mark.
In fact, C code is often faster and smaller than poorly written
assembler. High end PIC C compilers are really that good.
Obviously you have never used a proper high end C compiler on the PIC.

Dave

 

[CBarn24050]

Even so, your figures are still *way* off the mark.
In fact, C code is often faster and smaller than poorly written
assembler. High end PIC C compilers are really that good.
Obviously you have never used a proper high end C compiler on the PIC.

Dave

Well Dave I have a pic project I did 10 years ago, if you want to rewrite it in
C email me. Then we will know for sure.