[PATCH] libgcc/m68k: Fixes for soft float

[PATCH] libgcc/m68k: Fixes for soft float

Check for non-zero denorm in __adddf3. Need to check both the upper and
lower 32-bit chunks of a 64-bit float for a non-zero value when
checking to see if the value is -0.

Fix __addsf3 when the sum exponent is exactly 0xff to ensure that
produces infinity and not nan.

Handle converting NaN/inf values between formats.

Handle underflow and overflow when truncating.

Write a replacement for __fixxfsi so that it does not raise extra
exceptions during an extra conversion from long double to double.

libgcc/
	* config/m68k/lb1sf68.S (__adddf3): Properly check for non-zero denorm.
	(__divdf3): Restore sign bit properly.
	(__addsf3): Correct exponent check.
	* config/m68k/fpgnulib.c (EXPMASK): Define.
	(__extendsfdf2): Handle Inf and NaN properly.
	(__truncdfsf2): Handle underflow and overflow correctly.
	(__extenddfxf2): Handle underflow, denorms, Inf and NaN correctly.
	(__truncxfdf2): Handle underflow and denorms correctly.
	(__fixxfsi): Reimplement.