Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!rice!sun-spots-request
From: mcvax!ecn!marcel@uunet.uu.net (Marcel Bernards)
Newsgroups: comp.sys.sun
Subject: Re: SUN-4 FPU
Message-ID: <8902101002.AA10344@ecn.UUCP>
Date: 19 Feb 89 02:27:52 GMT
Sender: usenet@rice.edu
Organization: Sun-Spots
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Approved: Sun-Spots@rice.edu
Original-Date: Fri, 10 Feb 89 11:02:49 +0100
X-Sun-Spots-Digest: Volume 7, Issue 160, message 9 of 13
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In article <MONTNARO.89Feb1125820@sprite.steinmetz.ge.com> montanaro@sprite.steinmetz.ge.com writes:
>The Sun-4 compilers always assume that an FPU is installed. Without an FPU
>(as on Bruce Barnett's Sun-4/110) attempts to execute FP instructions
>cause a trap to the kernel, where they are then executed in software...

This is not quite true.

I tried some testprograms on our 4/110 and our 4/280S SUN.  The 4/110 is
delivered without FPU yes -> ;-(

The test program (from barnett@steinmetz.ge.com (Bruce Barnett)) I tested
results in the following data 

SUN 4/280-S Weitec Co's 
f=100000
0.2u 0.2s 0:00 68% 0+248k 9+0io 5pf+0w

SUN 4/110 NOCO
f=100000
1.2u 31.1s 0:32 99% 0+136k 2+9io 2pf+0w

SUN 3/50 68881 Diskless
f=100000
7.5u 2.2s 0:18 53% 0+96k 5+0io 7pf+0w

SUN 3/60 COLOR W SCSI + 68881 
f=100000
4.4u 1.1s 0:06 84% 0+96k 2+1io 2pf+0w

I used the following program with csh time command

main() {
      int i = 100000;
      double f = 0.0;
      while (i--) f += 1.0;
      printf("f=%g\n",f);
}

So SUN 4/110 _does_ emulate FP .

But VERY VERY SLOOOOOOOOW !!!!!!!!!!!

I think i'm gonna screw some budgets there ordering FPU for a 4/110 :-)

Marcel Bernards, UNIX & Net sysadm Netherlands Energy Research Foundation ECN
P.O. Box 1, 1755 ZG Petten, UUCP: marcel@ecn.UUCP, marcel%ecn.uucp@uunet.uu.net
PHONE: -31 2246 4342 ,EARN: ESU0130@HPEENR51L