Compilling with float?

[markusmueller19]

Posted on May 28, 2009 at 13:24

Compilling with float?

[markusmueller19]

Posted on May 17, 2011 at 12:36

With arm-none-eabi-gcc in thumb2 mode (GNU ld (Sourcery G++ Lite 2008q1-126) 2.18.50.20080215), 32 bit floats, exact CPU cycles

cos 4316 sin 4319 sqrt ??? atan 4440 add 92 mul 48 div 73

[16-32micros]

Posted on May 17, 2011 at 12:36

Hi Markus,

Thank you for your contribution and the results for GNU CodeSourcery so we can say that both : 1) Keil 3.22 , Option -03 Time + Not using ''MicroLib'' Option 2) IAR 5.11 , Option Full Speed Have quite the most optimized floating libraries running with STM32 in average :) Let's see the next builds of both Compilers coming in the next couple of weeks/months ;) Cheers, STOne-32.

[slawcus]

Posted on May 17, 2011 at 12:36

I have results for Rowley Crossworks 1.7 with no optimization, flash debug option and HW cycle counter at address 0xE0001004

cos: 2733 sin: 2637 sqrt: 2310 atan: 3590 add: 46 mul: 50 div: 138 for optimization level 2: cos: 2690 sin: 2594 sqrt: 2267 atan: 3547 add, mul and div were optimized away ;) And this were lib function for double!!! using float versions (32 bit) gives this results for no optimization cosf: 1288 sinf: 1190 sqrtf: 819 atanf: 1720 So ... the winner is? Anyway, we should also look at documentation for float libs. I think that super fast math doesn't even bother to check for valid data, supported types (single, double), etc. Rowley does all that. [ This message was edited by: slawcus on 20-06-2008 13:55 ]

[suyongyao]

Posted on May 17, 2011 at 12:36

This is what i get:

Cortex-M3, IAR 4.42a compiler 32 bit floats,exact CPU cycles cos 2947 sin 3053 sqrt 3566 atan 4778 add 71 mul 68 div 184

[alexcarrillo]

Posted on May 17, 2011 at 12:36

I'm having problems when using float (in operations such as adding 2 float variables).

I'm using the gcc compiler. What is the problem with float?

[markusmueller19]

Posted on May 17, 2011 at 12:36

if you use the ld for linkting, then you must have the right ranking order from your parameters. The -l parameters must be at end.

[bvisser]

Posted on May 17, 2011 at 12:36

Quote:

On 19-06-2008 at 19:26, Anonymous wrote: With arm-none-eabi-gcc in thumb2 mode (GNU ld (Sourcery G++ Lite 2008q1-126) 2.18.50.20080215), 32 bit floats, exact CPU cycles cos 4316 sin 4319 sqrt ??? atan 4440 add 92 mul 48 div 73 This information is very helpful! Thank you! Could you maybe run the same benchmark, but only with 64-bit floating point numbers (double)? I'm busy with a project that requires 64-bit precision and need to know it the Cortex M3 with GNU GCC will work.

[joseph239955]

Posted on May 17, 2011 at 12:36

The recent release v3.50 of KEIL tools has a newer version of library which should give a better floating processing speed when Microlib is used.

Could you try that with and see if the result is better? Thanks