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Old 07-17-2012, 09:38 AM   #32
knc1
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Quote:
Originally Posted by knc1 View Post
Maybe hard coding the look-up tables ...
A first step in that direction, get a look at what the compiler is seeing:
Code:
(armv6l:1) fft-arm-0.01 # export CFLAGS="-E"
(armv6l:1) fft-arm-0.01 # gcc $CFLAGS -o ffttest-arm.i radix4fft.c testfft.c testmain.c
Skipping past all the "include *.h" bull ...
Now it can be seen (and read) just how those thousands of trig. calls are used to init the lookup tables.

The ffttest-arm.i compiler input file is gzip'd and attached here.

Oops
The -E option doesn't do multiple *.c files into a single listing.
Ah, but the reader should get the idea, even if it has to be called 3 times.
Attached Files
File Type: gz ffttest-arm.i.gz (13.1 KB, 1374 views)

Last edited by knc1; 07-17-2012 at 10:00 AM.
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