In below discussion, i was informed that:
floating point arithmetic are not included within the ROM and SDK because they consume a lot of precious resources.
Re: Floating-Point Arithmetic
I made some simple tests best on hello sensor app on WICED 2.1.1
Test 1,
float a = 1.4;
float b = 2.9;
float c = a * b;
float d = b / a;
ble_trace2("c=%d, d=%d", c, d);
build passed and the output is c=4, d=2, which is a correct result.
However from the generated assembly(hello_sensor.s), i did not find any symbol like __aeabi_fmul or __aeabi_fdiv.
Test 2,
float my_fmul(float x, float y)
{
return x*y;
}
float my_fdiv(float x, float y)
{
return x/y;
}
float a = 1.4;
float b = 2.9;
float c = my_fmul(a, b);
float d = my_fdiv(b, a);
ble_trace2("c=%d, d=%d", c, d);
build passed and the result is "c=4, d=2" which is also a correct result.
From hello_sensor.s, i found below symbols:
| .global | __aeabi_fmul |
| bl | __aeabi_fmul |
| .global | __aeabi_fdiv |
| bl | __aeabi_fdiv |
I try to search which module did those two symbol reside in. Below is what i found in the generate list file:
_aeabi_cdrcmple ../tier2/brcm/mandatory/bld/20736/patch.elf
__aeabi_d2ulz ../tier2/brcm/mandatory/bld/20736/patch.elf
__aeabi_dadd ../tier2/brcm/mandatory/bld/20736/patch.elf
__aeabi_ddiv ../tier2/brcm/mandatory/bld/20736/patch.elf
__aeabi_dmul ../tier2/brcm/mandatory/bld/20736/patch.elf
__aeabi_drsub ../tier2/brcm/mandatory/bld/20736/patch.elf
__aeabi_dsub ../tier2/brcm/mandatory/bld/20736/patch.elf
__aeabi_fdiv ../../build/hello_sensor_tmp-BCM920736TAG_Q32-rom-ram-Wiced-release/hello_sensor.o
__aeabi_fmul ../../build/hello_sensor_tmp-BCM920736TAG_Q32-rom-ram-Wiced-release/hello_sensor.o
__aeabi_lasr ../tier2/brcm/mandatory/bld/20736/patch.elf
__aeabi_llsl ../tier2/brcm/mandatory/bld/20736/patch.elf
__aeabi_llsr ../tier2/brcm/mandatory/bld/20736/patch.elf
__aeabi_memclr ../tier2/brcm/mandatory/bld/20736/patch.elf
__aeabi_memclr4 ../tier2/brcm/mandatory/bld/20736/patch.elf
I still have no idea where did these symbol come from:-(
Test 3:
A little bit modification on below function:
float my_fmul(float x, float y)
{
x =x*y*x; // added
return x*y;
}
Build OK.
Test 4:
Added one more line:
float my_fmul(float x, float y)
{
x =x*y*x;
y = x*y*x; // added
return x*y;
}
Clean and build again, but this time i got many errors like:
C:\Data\Work\Broadcom\BLE\WICED_Smart_SDK\WICED-Smart-SDK-2.1.1\WICED-Smart-SDK_Test\Wiced-Smart\spar/../../Apps/hello_sensor_tmp/hello_sensor.c:398: undefined reference to `__aeabi_fmul'
I also check __aeabi_fmul and __aeabi_fdiv, they still appear in the hello_sensor.s and ***.list file.
why, why, why?
Any one can help me?
thanks
