STM CircleOS forum / Float / double math on CircleOS

Tomorokoshi · 2007-10-19 23:17:04

I am working on something that will need floating point math. I can declare doubles, but I don't seem to get good math results, and there are no functions or output routines that use them.

Is this something in the works for a future update? Is anyone else working on adding floating point math to it?

Francis · 2007-10-20 04:38:24

There is not any use of the loating point numbers in the CircleOS. But you are free to use float/double in your application. The math libraries provided with GCC will be added by the linker to your application (that will be probably big...).

Tomorokoshi · 2007-10-20 05:34:08

I tracked down part of my initial problem, and now it seems I can use the float math. However, I am using too much, because I get the following error:

----------------Make Started: 'PocketC5' in configuration 'Circle_Release'--------------------------

Building D:\Raisonance\Ride\Examples\PocketC5.rapp
Running : LD
\arm-none-eabi-gcc.exe -mcpu=cortex-m3 -mthumb -Wl,-T -Xlinker "D:\Raisonance\Ride\Examples\objrelease\PocketC5.elf.ld" -u _start -Wl,-static -Wl,--gc-sections -nostartfiles -Wl,-Map -Xlinker "D:\Raisonance\Ride\Examples\objrelease\PocketC5.map"
d:/raisonance/ride/arm-gcc/bin/../lib/gcc/arm-none-eabi/4.2.0/../../../../arm-none-eabi/bin/ld.exe: region FLASH is full (D:\Raisonance\Ride\Examples\objrelease\PocketC5.elf section .text)
rdimon-ram.ld:1: undefined symbol `!!!!!!!!! FLASH IS FULL !!!!!!!!!' referenced in expression
collect2: ld returned 1 exit status

Build failed

In other words, I am filling up the flash with a combination of float math and sprintf() to write a float variable to a text string. I set it to tiny printf, release mode, and optimize for size, but I cannot free enough memory. Because the compile fails, there is no memory map. What is the best way to determine how much memory I need to free to make it work?

Francis · 2007-10-20 09:20:09

You reached the 32 KB limitation.
However the software tools are not really limited (only debugging with the embedded RLink). Therefore, you can pass over this message by modifying the LD script file.

ThomasScherrer · 2007-11-02 11:43:20

I included #include <math.h>
but cant x=sin(y);
get just Build Failed !
what is wrong ?

Tomorokoshi · 2007-11-02 13:37:29

It seems that the functions for floating point math are not there. I will need to write my own 10^x, sqrt(x), and simple sprintf() routines.

The actual floating point math addition, subtraction, multiplication, and division seem to work. You should be able to find a lot about how to write those routines. The design of CircleOS seems to be that a minimum amount is provided to allow maximum space for other things.

ThomasScherrer · 2007-11-02 13:56:25

YIKES, I am not writing my own, it must be possible simply to include math.h the right place
and then get access to math ??
it can't be right this is not possible

ThomasScherrer · 2007-11-02 14:15:32

>Therefore, you can pass over this message by modifying the LD script file.

HOW ??
can you please explain how this is done ?

Francis · 2007-11-02 14:19:34

I just opened a project, included math.h and checked that the following code works properly. It does.

float myf = 0;
void test ( void )
{
myf = 2*asin(1);
}

Check the path of the "include" directories.

auto.response · 2009-02-07 21:15:09

It's looke like I have a similar problem.

#include <math.h>

...

void test_func()
{
float calc_result_1 = 0.0;
float calc_result_2 = 0.0;
float test_value = 0.6;

calc_result_1 = atanf(0.6); // works ok
//calc_result_2 = atanf(test_value); // uncommented and the following error message appears
}

----------------Build Started: 'Mems' in configuration 'Circle_Debug'--------------------------

Building C:\Programme\Raisonance\Ride\Examples\ARM\Primer\STM32\Mems\src\Mems.c
Running: GCC
\"C:\Programme\Raisonance\Ride\arm-gcc\bin\arm-none-eabi-gcc.exe" -MD -D_STM32F103RBT6_ -D_STM3x_ -D_STM32x_ -mthumb -mcpu=cortex-m3 "C:\Programme\Raisonance\Ride\Examples\ARM\Primer\STM32\Mems\src\Mems.c" -o "C:\Programme\Raisonance\Ride\Examples\ARM\Primer\STM32\Mems\src\objdebug\Mems.o" -I "." -I "C:\Programme\Raisonance\Ride\Lib\ARM\include" -c -fsigned-char -g -ffunction-sections -mlittle-endian
\"C:\Programme\Raisonance\Ride\Bin\rexrdr.exe" "C:\Programme\Raisonance\Ride\Examples\ARM\Primer\STM32\Mems\src\objdebug\Mems.lst" 0 "C:\Programme\Raisonance\Ride\arm-gcc\bin\arm-none-eabi-objdump.exe" --disassemble -all --source "C:\Programme\Raisonance\Ride\Examples\ARM\Primer\STM32\Mems\src\objdebug\Mems.o"
\"C:\Programme\Raisonance\Ride\Bin\rexrdr.exe" "C:\Programme\Raisonance\Ride\Examples\ARM\Primer\STM32\Mems\src\objdebug\Mems.o.sizetmp" 0 "C:\Programme\Raisonance\Ride\arm-gcc\bin\arm-none-eabi-size.exe" "C:\Programme\Raisonance\Ride\Examples\ARM\Primer\STM32\Mems\src\objdebug\Mems.o"

Building C:\Programme\Raisonance\Ride\Examples\ARM\Primer\STM32\Mems\src\Mems.rapp
Running: LD
\"C:\Programme\Raisonance\Ride\arm-gcc\bin\arm-none-eabi-gcc.exe" -mcpu=cortex-m3 -mthumb -Wl,-T -Xlinker "C:\Programme\Raisonance\Ride\Examples\ARM\Primer\STM32\Mems\src\objdebug\Mems.elf.ld" -u _start -nostartfiles -Wl,-Map -Xlinker "C:\Programme\Raisonance\Ride\Examples\ARM\Primer\STM32\Mems\src\objdebug\Mems.map"
c:/programme/raisonance/ride/arm-gcc/bin/../lib/gcc/arm-none-eabi/4.3.2/../../../../arm-none-eabi/bin/ld.exe: C:\Programme\Raisonance\Ride\Examples\ARM\Primer\STM32\Mems\src\objdebug\Mems.elf section .text will not fit in region FLASH
c:/programme/raisonance/ride/arm-gcc/bin/../lib/gcc/arm-none-eabi/4.3.2/../../../../arm-none-eabi/bin/ld.exe: region FLASH overflowed by 1328 bytes
collect2: ld returned 1 exit status

Build failed

I use the following versions:

Ride7 IDE v7.16.0000
RKit-ARM for Ride7 v1.16.0930

How can I solve this ?
Thanks for help.

#########################################
==> Following works for me:
GCC Compiler
Optimization level: Size optimization

Last edited by auto.response (2009-02-07 21:37:05)

sjoerd · 2009-02-07 21:50:58

You need to extend the flash region in the .ld file of your project.

For example:
FLASH (rx) : ORIGIN = 0x8006000, LENGTH = 16K

also change _eflash accordingly.

auto.response · 2009-02-08 01:01:03

Thanks sjoerd.

I added the Circle_App.ld file to my project list and
changed the size.

[CODE]
...
MEMORY
{
RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 16K
FLASHB1 (r) : ORIGIN = 0x8000000, LENGTH = 0x0006000
/*before*/// FLASH (rx) : ORIGIN = 0x8006000, LENGTH = 8K
/*after*/ FLASH (rx) : ORIGIN = 0x8006000, LENGTH = 16K
EXTMEMB0 (rx) : ORIGIN = 0x00000000, LENGTH = 0
EXTMEMB1 (rx) : ORIGIN = 0x00000000, LENGTH = 0
EXTMEMB2 (rx) : ORIGIN = 0x00000000, LENGTH = 0
EXTMEMB3 (rx) : ORIGIN = 0x00000000, LENGTH = 0
}

/* higher address of the flash allowed for the program */
_eflash = 0x8006000 + 16K -1;
...
[\CODE]

But I don't know what to change at "_eflash = 0x8006000 + 16K -1;"
so I changed nothing (it works fine).

For explanations I found this:
http://www.stm32circle.com/forum/viewtopic.php?id=129

# 1 2007-10-19 23:17:04 Float / double math on CircleOS

Float / double math on CircleOS

# 2 2007-10-20 04:38:24 Float / double math on CircleOS

Re: Float / double math on CircleOS

# 3 2007-10-20 05:34:08 Float / double math on CircleOS

Re: Float / double math on CircleOS

# 4 2007-10-20 09:20:09 Float / double math on CircleOS

Re: Float / double math on CircleOS

# 5 2007-11-02 11:43:20 Float / double math on CircleOS

Re: Float / double math on CircleOS

# 6 2007-11-02 13:37:29 Float / double math on CircleOS

Re: Float / double math on CircleOS

# 7 2007-11-02 13:56:25 Float / double math on CircleOS

Re: Float / double math on CircleOS

# 8 2007-11-02 14:15:32 Float / double math on CircleOS

Re: Float / double math on CircleOS

# 9 2007-11-02 14:19:34 Float / double math on CircleOS

Re: Float / double math on CircleOS

# 10 2009-02-07 21:15:09 Float / double math on CircleOS

Re: Float / double math on CircleOS

# 11 2009-02-07 21:50:58 Float / double math on CircleOS

Re: Float / double math on CircleOS

# 12 2009-02-08 01:01:03 Float / double math on CircleOS

Re: Float / double math on CircleOS

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