> > Any one know how to use float point in mips kernel?
> > We use some 2.4.5 kernel, on idt mips 32334, which has no fpu, I
think.
> > we want to use the float numbers like this:
> > float a = 87;
> > a * = 1.04;
> > Any kernel functions to do this? or how to compile it use soft fpu
> > support?
>
> The way I integrated the Algorithmics FPU emulaton
> code into the kernel *used* to work for kernel FP.
> Maybe someone has broken it since, and there may
> well be situations where it was unsafe, but have you
> tried simply confuguring FPU emulation and running
> your code with it?
>
I have checked it, the FPU support is in the kernel.
My kernel can't boot without the FPU emulation support.
that's the module code:
#################
float a = 1.03;
double b = 1.05;
int init_module (void)
{
a = 39 * a;
b /= 34*(1.01 + a);
printk("\nthe result is : %f", b);
return 0;
}
void cleanup_module (void)
{
return;
}
######################
insmod this module to the kernel, kernel will report
[insmod:25] Illegal instruction 81700000 at 8170007c ra=80017fac
...
I look into the module's code,
and that's inst(objdump):
40: d4240008 0xd4240008
...
1c: d4240128 0xd4240128
...
74: f4240008 0xf4240008
...
these are in .text section.
The other mfc1, swc1 inst in code are ok.
Then I try to use soft float .
compile like this:
mipsel-linux-gdb ..... -msoft-float ... -o fp_tmp.o -c fp.c
mipsel-linux-ld -r -EL -static -L/opt/Embdeix/tools/mipsel-linux/lib
-lm -o fp.o fp_tmp.o
(I use lineo's Embedix SDK2.0)
and when insmod fp1.o , U comes:
fp.o: unresolved symbol dpadd
fp.o: unresolved symbol fpmul
fp.o: unresolved symbol fptodp
fp.o: unresolved symbol dpmul
fp.o: unresolved symbol dpdiv
the gcc's maual says in mips when use -msoftfloat ,
should get some special-compiled lib routines.
Is that dpadd, fpmul ,etc?
How to get that special-compiled lib?
