Soft Floating Point Exceptions

[Brian Inglis]

On 2020-05-25 11:17, Joel Sherrill wrote:
> An RTEMS GSoC student (Eshan Dhawan) has almost completed porting the
> FreeBSD fenv code to newlib. Unfortunately, the software floating point
> code calls  __softfloat_float_raise which has a couple of issues. First, he
> can't find the code which probably indicates an issue in the BSD world but
> no one likely cares because I doubt there is a BSD install on an ARM with
> soft floating point.
> 
> Second, to use this in newlib, we will be relying on GCC's soft float
> implementation which means something different has to happen. Is there an
> equivalent routine in GCC? What should happen for
> __softfloat_float_raise()?

You will have to look at these to see what is relevant to your issue.

Interface:

$ info gccint libgcc soft

implementation:

https://gcc.gnu.org/git?p=gcc.git;a=blob_plain;f=libgcc/config/arm/sfp-machine.h;hb=HEAD
https://gcc.gnu.org/git?p=gcc.git;a=blob_plain;f=libgcc/config/arm/ieee754-sf.S;hb=HEAD
https://gcc.gnu.org/git?p=gcc.git;a=blob_plain;f=libgcc/config/arm/ieee754-df.S;hb=HEAD
https://gcc.gnu.org/git?p=gcc.git;a=blob_plain;f=libgcc/config/arm/fp16.c;hb=HEAD

implementation:

https://github.com/freebsd/freebsd/commit/85aab3336e0d6172ddd5fe3cde38389abd612728
https://github.com/freebsd/freebsd/tree/master/lib/libc/softfloat
https://github.com/freebsd/freebsd/blob/master/lib/libc/softfloat/softfloat.txt#L357
https://github.com/freebsd/freebsd/blob/master/lib/libc/softfloat/softfloat-for-gcc.h
https://github.com/freebsd/freebsd/blob/master/lib/libc/softfloat/softfloat-specialize#L67

alternative:

http://cvsweb.netbsd.org/bsdweb.cgi/src/lib/libc/arch/arm/softfloat/

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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