hi Jonathan,

 * Re:
   dd.  29-12-95, 12:52:00
   from Jonathan de Boyne Pollard, 2:440/4
   to   Mike Bilow
 hl>>> What FPU?  My 386 doesn't have one...  How good is OS/2s
 hl>>> emulator in doing this stuff?
 >> 
 >> There is no reasonable way to code these things other than
 >> to issue FPU instructions.  If there is no FPU, then an
 >> exception is generated and the FPU instruction is emulated
 >> in software by some library facility.  Under OS/2 for
 >> native OS/2 programs, the operating system does it for you
 >> in NPXEMLTR.DLL.
 JdBP>   I think that Hugo was asking how good the emulator is in terms of  
 JdBP> numerical accuracy.

Well, maybe I was asking two questions in one...  I knew there is an
emulator (and even virtual access to it from DOS-boxes).  Accuracy is one
part of the question, with the other part being: how much is it needed?  I
imagine the emulator is factors slower than the real thing, so it boils
down to where would a 387 be used?  Only in numerical-inclined programs, or
would I see an overall system performance boost by adding one?  Its cost
has come down enough in the last year to issue such a question - even for
this antique hardware -, I think.

 JdBP>   In light of the present discussion (as to the NPX differences
 JdBP> between   a 387 and a 486), it is also relevant to ask which NPX
 JdBP> instruction set   is emulated by OS/2.  I'd expect it to be the
 JdBP> 387, since that is the   only significant case where one would
 JdBP> *need* NPX emulation, but ...

As long as OS/2 only requires a 386(sx) to run, it wouldn't make much sence
for it to emulate 487s (or PentiumPro's) [but then, I would by disappointed
if Merlin wouldn't boot...].

regards,
         hugo