Article View: comp.sys.dec
Article #4993Re: difference between vax floating point representation and IEEE
From: Dan Packman
Date: Fri, 22 Jul 1988 22:37
Date: Fri, 22 Jul 1988 22:37
62 lines
2469 bytes
2469 bytes
In article <2256@hubcap.UUCP> ghosh@hubcap.UUCP (Amitava Ghosh) writes:
>does anyone know what the difference is between the IEEE floating
>point representation and the way the VAX stores numbers. If so
>how does one convert from one format to the other...
The following program converts from vax f format to IEEE (UNIX point of view)
--------cut here-------------
subroutine vax2lcl(n,iarray)
dimension iarray(n)
character*1 conv(4),ccc
integer iconv
equivalence (iconv,conv)
c Convert from vax floating point f format to pyramid IEEE single
do 10 i=1,n
iconv=iarray(i)
if (iconv.ne.0) then
ccc=conv(1)
iii=ichar(conv(2))-1
if (iii.lt.0)then
write(0,100)iconv
100 format(' vax2lcl: overflow int in =',i10)
call exit(1)
endif
conv(1)=char(iii)
conv(2)=ccc
ccc=conv(3)
conv(3)=conv(4)
conv(4)=ccc
iarray(i)=iconv
endif
10 continue
return
end
--------cut here-------------
The following converts an array of IEEE single floats to vax floats
It is written to work on a VAX/VMS machine
--------cut here-------------
subroutine pyr2lcl(n,iarray)
dimension iarray(n)
byte conv(4),ccc
integer iconv
equivalence (iconv,conv)
c Convert from pyramid IEEE single to vax floating point f format
do 10 i=1,n
iconv=iarray(i)
if (iconv.ne.0) then
ccc=conv(2)
iii=conv(1)+1
if (iii.gt.255)then
write(0,100)iconv
100 format(' pyr2lcl: overflow int in =',i10)
call exit(1)
endif
conv(2)=iii
conv(1)=ccc
ccc=conv(3)
conv(3)=conv(4)
conv(4)=ccc
iarray(i)=iconv
endif
10 continue
return
end
Technical Details
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!husc6!mailrus!ames!ncar!acdpyr!pack From: pack@acdpyr.ucar.edu (Dan Packman) Newsgroups: comp.sys.dec,comp.os.vms Subject: Re: difference between vax floating point representation and IEEE Summary: IEEE floating point to/from VAX floating point Keywords: IEEE vax floating Message-ID: <471@ncar.ucar.edu> Date: 22 Jul 88 22:37:55 GMT References: <2256@hubcap.UUCP> Sender: news@ncar.ucar.edu Reply-To: pack@acdpyr.UCAR.EDU (Dan Packman) Organization: Atmospheric Chemistry Division/NCAR, Boulder CO Lines: 62