Assembler library

Forum 2005-2010 (read only) Software Development
1

Hi you all,
I have a rather humble question: a friend of mine :wink: has a good and superfast routine written in assembler for Atmel168, and he wants to use it on Arduino, compiling it as a library. Now he as two files: the header file (superlibrary.h) and the assembler file (superlibrary.S). Being keen, he toss both files within hardware/libraries/Superlibrary and fires up Arduino. Rather surprisingly, no compilation occours and no messages are printed on console, even if the avr-gcc is expected to drink .S files as well as .c files.
I told my friend that probably the somewhere there's a Makefile missing a .S rule... but is there someone having a better and more detailed explanation? or perhaps a solution?
Thanks a lot,
Paolo

2

Jeez... no one replying. Perhaps this is the wrong forum section?

3

Hi Paolo,

I doubt many here are writing anything for the arduino in assembler. The few cases where assembler code is faster than optimized C code, the assembler has been embedded in a C or C++ file using the asm directive. That is one way to get the assembler code recognized by the arduino build process.

What does the routine do?

4

Mem, thanks for your reply.
The routine does the fast Fourier transform of an array of data. The fact is that it is not a product of mine, and I'm not so fluent in reading and understanding assembler. So I would like to use it as is, but it's kinda long (~600 lines) to be included with the asm directive.
Of course I could write a new routine by my own, but I'm used to be lazy, you know, and moreover looks like that routine (named avrfft) scores quite good in terms of efficiency.
Thanks again,
-P.

5

Perhaps something in these links will help:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1218921378
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1201426232/3#3

6

I'm actually interested in this issue due to the use of assembler in my Arduino and AVRUSB integration.

I think the short answer is that the way the IDE calls the avrgcc compiler doesn't include .S files automatically. I suspect inline asm directives might be the easiest approach (I don't think I can use them though as the code I use also "includes" more asm files) although another option would be to write a patch for the IDE. :slight_smile:

What I ended up doing is compiling the .S files separately and then putting the .o files generated in the library directory and they did get picked up.

--Phil.

7

Thanks, follower. In fact I was suspecting something like that.
I'll try to compile it by hand...

8

I am using .S assembler files in my core. follower is right, you have to modify you IDE.

A first step is to find this line in Target.java:

if (files_.endsWith(".c") || files*.endsWith(".cpp"))_
and replace it with this line:
if (files.endsWith(".S") || files_.endsWith(".c") || files.endsWith(".cpp"))*
and then you have to modify the Compiler.java and get the .S files into the build process.
I have a modified Arduino IDE that can compile the assembler files, I will try to create a patch if you are still interested._

9

I will try to create a patch if you are still interested.

That would be helpful. :slight_smile:

--Phil.

10

You can find the "LumiNet patch" in this thread:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1236434254

this patch should work with all Arduino boards and includes the "assembler patch". Tell me if this is working for you or if I need to create an isolated "assembler patch".

11

Any body add fft library in Arduino project?