Re: real.c on unicosmk

[Kevin Handy <kth at srv dot net>]

Zack Weinberg wrote:

>On Thu, May 23, 2002 at 12:32:27PM -0400, Paul Koning wrote:
>  
>
>>Excerpt of message (sent 22 May 2002) by Zack Weinberg:
>>    
>>
>>>On Wed, May 22, 2002 at 03:40:10PM -0700, Joe Buck wrote:
>>>      
>>>
>>>>>>In 3.2, REAL_ARITHMETIC is unconditionally on all the time.  It's
>>>>>>amazing how much crap vanishes when there is only one supported method
>>>>>>of doing floating-point calculations.
>>>>>>            
>>>>>>
>>>>>What do you intend to do about these eleven other GCC ports, then?
>>>>>They had not been fixed to use REAL_ARITHMETIC, and for some (like
>>>>>convex) the fix might be difficult.
>>>>>
>>>>>1750a a29k clipper convex d30v elxsi fr30 i860 ns32k pdp11 romp
>>>>>          
>>>>>
>>>>About half of these need to go away: for example, there is not a single
>>>>elxsi machine in the world.
>>>>        
>>>>
>>>Of this list, only d30v fr30 ns32k pdp11 romp are still supported
>>>targets.  None of these claim to use anything other than IEEE floating
>>>point.  Where that is inaccurate, it needs to be fixed.
>>>      
>>>
>>It certainly is inaccurate for the PDP11, which predates IEEE float by
>>many years.  It uses VAX float formats.  I recently changed gas to
>>know that.
>>
>>This sounds like one of the lesser pdp11 target problems, but thanks
>>for noting it...
>>    
>>
>
>The fix should be as simple as adding 
>
>#define TARGET_FLOAT_FORMAT VAX_FLOAT_FORMAT
>
>to pdp11.h.
>
>(The PDP-11 came before the VAX, so perhaps it would be appropriate to
>rename VAX_FLOAT_FORMAT to PDP11_FLOAT_FORMAT.)
>  
>
FWIW: I don't know which VAX floating point types are emulated, but you 
need some
care with them. The PDP11 only has a subset of the VAX floating point 
 types:
SINGLE and DOUBLE only.  The GFLOAT and HFLOAT VAX types are
not  available to the PDP11. At least as far as I ever knew.