Board index » delphi » Converting Type - Real(Pascal) to Visual Basic

Tomek

Delphi Developer
Tue, 03 Aug 2004 21:02:51 GMT

Converting Type - Real(Pascal) to Visual Basic

I have data base (btrieve), where files where created in Pascal and uses
Real Type (digits 6  decimal-2) and I need to find a way to read these data
by Visual Basic
For example:
Number (33,33) is representing as  ( (134) (31) (133) (235) (81) (5))  or
(?-?Q )
How from byte representation find the number 33.33
Thanks
 
Markus Hum

Delphi Developer
Wed, 04 Aug 2004 01:02:31 GMT

Re:Converting Type - Real(Pascal) to Visual Basic


Quote
Tomek wrote:
> I have data base (btrieve), where files where created in Pascal and uses
> Real Type (digits 6  decimal-2) and I need to find a way to read these data
> by Visual Basic
> For example:
> Number (33,33) is representing as  ( (134) (31) (133) (235) (81) (5))  or
> (?-?Q )
> How from byte representation find the number 33.33
> Thanks

you can't convert them with Pascal to EXTENDED or DOUBLE? Because
EXTENDED or DOUBLE are IEEE compliant types...Real is some proprietary
Borland stuff...

Greetings

Markus

Dr John Stockto

Delphi Developer
Wed, 04 Aug 2004 05:10:39 GMT

Re:Converting Type - Real(Pascal) to Visual Basic


JRS:  In article <3C6D314A.62666...@yahoo.com>, seen in
news:comp.lang.pascal.ansi-iso, CBFalconer <cbfalco...@yahoo.com> wrote
at Fri, 15 Feb 2002 16:32:39 :-

Quote
>Tomek wrote:

>> I have data base (btrieve), where files where created in Pascal
>> and uses Real Type (digits 6  decimal-2) and I need to find a
>> way to read these data by Visual Basic
>> For example:
>> Number (33,33) is representing as:
>>    ( (134) (31) (133) (235) (81) (5))  or   (?-?Q )
>> How from byte representation find the number 33.33

>Write it out in hex or binary and examine the pattern.  If you are
>lucky you will find it is an IEEE std format.  I don't think you
>understand the makeup of floating point formats from the tone of
>your question, so you would be well advised to read Knuth.

Now if you only knew TurboPascal...  Is there an IEEE 6-byte format??

In <URL:http://www.merlyn.demon.co.uk/programs/>, sixbytes.pas is a
short TP program containing a routine to convert a six-byte real, using
arithmetic, to a number (expressed as a ten-byte Extended, but trivial
to change).

The routine SixToExt takes a "real" argument, and casts it to an array
[1..6] of byte; the argument could trivially be supplied as an array.

TP code is easy enough to read; probably the OP will be able to
translate into his preferred language.

OP: please do not multi-post.

Cross-posted c.l.p.a-i, c.l.p.b; FU c.l.p.b

--
? John Stockton, Surrey, UK.  j...@merlyn.demon.co.uk   Turnpike v4.00   MIME. ?
 Web  <URL:http://www.merlyn.demon.co.uk/> - FAQqish topics, acronyms & links.
 PAS, EXE in  <URL:http://www.merlyn.demon.co.uk/programs/> - see 00index.txt.
 Do not Mail News to me.    Before a reply, quote with ">" or "> " (SoRFC1036)

R. A. Larse

Delphi Developer
Wed, 04 Aug 2004 08:32:35 GMT

Re:Converting Type - Real(Pascal) to Visual Basic


Quote
"Tomek" <xx20...@wp.pl> wrote:

> I have data base (btrieve), where files where created in Pascal and uses
> Real Type (digits 6  decimal-2) and I need to find a way to read these data
> by Visual Basic
> For example:
> Number (33,33) is representing as  ( (134) (31) (133) (235) (81) (5))  or
> (?-?Q )
> How from byte representation find the number 33.33
> Thanks

The 'real' type is defined as:

    width in bits
    1                   39                      8
   +-+---------------------------------------+--------+
   |s|                  f                    |  e     |
   +-+---------------------------------------+--------+

and the value v is calculated as:

    if 0 < e <= 255 then v = (-1)^s * 2^(e-129) * (1.f)
    if e = 0 then v = 0

where '^' means power. This comes directly from the "TP6 Programmer's Guide".

Regards, Ren
--
Using Virtual Access
http://www.vamail.com

Valentine Mehlin

Delphi Developer
Wed, 04 Aug 2004 13:32:27 GMT

Re:Converting Type - Real(Pascal) to Visual Basic


I am gradually migrating my apps from TP7 to VB5. The simplest way I have found
to move numeric values from TP to VB is to simply store the data in a text
file. VB can easily read the file and you can write a routine to convert the
text representation to whatever data type you need.

Quote
Tomek wrote:
> I have data base (btrieve), where files where created in Pascal and uses
> Real Type (digits 6  decimal-2) and I need to find a way to read these data
> by Visual Basic
> For example:
> Number (33,33) is representing as  ( (134) (31) (133) (235) (81) (5))  or
> (?-?Q )
> How from byte representation find the number 33.33
> Thanks

--
Val Mehling
va...@earthlink.net

Web Pages
http://home.earthlink.net/~valjm/

XRL (Extreme Racing League) Pics
http://odin.prohosting.com/~valjm

http://odin.prohosting.com/valmeh/

Scott Moor

Delphi Developer
Wed, 04 Aug 2004 15:44:34 GMT

Re:Converting Type - Real(Pascal) to Visual Basic


Quote
Dr John Stockton wrote:

> JRS:  In article <3C6D314A.62666...@yahoo.com>, seen in
> news:comp.lang.pascal.ansi-iso, CBFalconer <cbfalco...@yahoo.com> wrote
> at Fri, 15 Feb 2002 16:32:39 :-
> >Tomek wrote:

> >> I have data base (btrieve), where files where created in Pascal
> >> and uses Real Type (digits 6  decimal-2) and I need to find a
> >> way to read these data by Visual Basic
> >> For example:
> >> Number (33,33) is representing as:
> >>    ( (134) (31) (133) (235) (81) (5))  or   (?-?Q )
> >> How from byte representation find the number 33.33

> >Write it out in hex or binary and examine the pattern.  If you are
> >lucky you will find it is an IEEE std format.  I don't think you
> >understand the makeup of floating point formats from the tone of
> >your question, so you would be well advised to read Knuth.

> Now if you only knew TurboPascal...  Is there an IEEE 6-byte format??

Well, to be fair he said six digits. To tell you the truth, its been a
while since I did 32 bit float, but 6-8 digits might be about right.
I would start by dumping out zero (a floating point zero), and seeing
what that matches.

- Show quoted text -

Quote

> In <URL:http://www.merlyn.demon.co.uk/programs/>, sixbytes.pas is a
> short TP program containing a routine to convert a six-byte real, using
> arithmetic, to a number (expressed as a ten-byte Extended, but trivial
> to change).

> The routine SixToExt takes a "real" argument, and casts it to an array
> [1..6] of byte; the argument could trivially be supplied as an array.

> TP code is easy enough to read; probably the OP will be able to
> translate into his preferred language.

> OP: please do not multi-post.

> Cross-posted c.l.p.a-i, c.l.p.b; FU c.l.p.b

> --
> ? John Stockton, Surrey, UK.  j...@merlyn.demon.co.uk   Turnpike v4.00   MIME. ?
>  Web  <URL:http://www.merlyn.demon.co.uk/> - FAQqish topics, acronyms & links.
>  PAS, EXE in  <URL:http://www.merlyn.demon.co.uk/programs/> - see 00index.txt.
>  Do not Mail News to me.    Before a reply, quote with ">" or "> " (SoRFC1036)

Dr John Stockto

Delphi Developer
Thu, 05 Aug 2004 03:07:15 GMT

Re:Converting Type - Real(Pascal) to Visual Basic


JRS:  In article <3C6E0DE2.111DB...@moorecad.com>, seen in
news:comp.lang.pascal.borland, Scott Moore <sam...@moorecad.com> wrote
at Fri, 15 Feb 2002 23:44:34 :-

Quote
>I would start by dumping out zero (a floating point zero), and seeing
>what that matches.

Every bit of a normal floating point zero, of whatever type, is zero in
Borland's Pascals & Delphi; I don't know about Kylix.

Some patterns with some bits non-zero may also be interpreted as zero.

In announcing your new WWW address, you also gave the old one.  Few are
so thoughtful; it makes updating much easier.

--
? John Stockton, Surrey, UK.  j...@merlyn.demon.co.uk   Turnpike v4.00   MIME. ?
  <URL:http://www.merlyn.demon.co.uk/> TP/BP/Delphi/&c., FAQqy topics & links;
  <URL:http://www.merlyn.demon.co.uk/clpb-faq.txt> Pedt Scragg: c.l.p.b. mFAQ;
  <URL:ftp://garbo.uwasa.fi/pc/link/tsfaqp.zip> Timo Salmi's Turbo Pascal FAQ.

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