MPC8xx fpu support and compiling glib.

Wolfgang Denk wd at denx.de
Fri Apr 12 23:37:09 EST 2002


In message <3CB60E13.BA0A4A6 at esteem.com> you wrote:
>
> 	I was wondering a few things about MPC8xx FPU support. If
> I build a kernel with fpu-emulation do I have to pass the CFLAGS

That makes only sense when your application AND libraies DO  NOT  use
soft-float.

> "-msoft-float -D_SOFT_FLOAT" when compiling glibc? Does it save me

You cannot mix FPU-code and  soft-float  in  one  application/library
setup.

> any ram if I don't? I know if I don't my performance will drop but
> our aplication doesn't use floating point except for ping mabey.

Ummm... why should soft-float result in _smaller_ code? On contrary -
the code will be bigger, but run faster since you don;t have to  trap
into the kernel for each FP instruction.

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
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