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Re: Can Java compute 9^(9^9) ?

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So I guess it has been settled that VAX had something
for decimals. What I dont know whether PDP had something
for decimals.

Here is a nice story about DEC: Ken Olsen 1957 - 1989
https://www.youtube.com/watch?v=VEf2Xf7Urn8

Am Montag, 11. Juni 2018 00:52:33 UTC+2 schrieb burs...@gmail.com:
> Here is a list which VAX had decimal fp, and which not,
> in micro code and not in macro code:
> 
> VAX Processor Charts		Rev 7 15-Sep-2000
> http://simh.trailing-edge.com/docs/vax_proc.txt
> 
> y	=	implemented in hardware/microcode
> n	=	emulated in macrocode
> 
> It lists the processor model, and then yoi have to lookup
> the VAX model.
> 
> Am Montag, 11. Juni 2018 00:48:31 UTC+2 schrieb burs...@gmail.com:
> > For VAX it was possibly option 2), at least
> > wikipedia says:
> > 
> >     Architectures with instruction sets 
> >     implemented by complex microprograms 
> >     included the IBM System/360 and Digital 
> >     Equipment Corporation VAX. 
> >     https://en.wikipedia.org/wiki/Microcode
> > 
> > And the instructions were so called decimal
> > string instructions, I guess:
> > 
> > Decimal =	Decimal instruction group
> > 
> > 		ADDP4	ADDP6	ASHP	CMPP3	CMPP4
> > 		CVTLP	CVTPL	CVTPS	CVTPT	CVTSP
> > 		CVTTP	DIVP	MOVP	MULP	SUBP4
> > 		SUBP6
> > 
> > Because there is always a length parameter,
> > I guess option 1) does not really exist. At
> > least if the aim is decimal strings.
> > 
> > Am Montag, 11. Juni 2018 00:29:14 UTC+2 schrieb Arne Vajhøj:
> > > On 6/10/2018 5:31 AM, bursejan@gmail.com wrote:
> > > > Am Sonntag, 10. Juni 2018 11:13:19 UTC+2 schrieb Martin Gregorie:
> > > >> On Sat, 09 Jun 2018 23:29:53 +0000, Volker Borchert wrote:
> > > >>> j4n bur53 wrote:
> > > >>>> Interestingly IBM, also for their new POWER9,
> > > >>>> still provides BCD coding support.
> > > >>>
> > > >>> Is it part of ANSI COBOL?
> > > >>>
> > > >> Its been a long time since I wrote any COBOL, and I've never done so on
> > > >> IBM kit [only ICL 1900 (24bit word, 6bit char), ICL 2900 (byte-oriented),
> > > >> DEC VAX, Tandem and NCR UNIX (Intel chips)] and AFAIK none of these
> > > >> machines supported BCD arithmetic at the hardware level.
> > > >>
> > > >> COBOL specifies a number of numeric representations which include COMP
> > > >> (fixed length numeric strings), DISPLAY (formatted character strings)
> > > >> COMP SYNC (native binary representations) and a few others (COMP-n)
> > > >> including floating point. I think you'll find that the internal
> > > >> representation of COMP variables is undefined by the standard as long as
> > > >> manipulating it works to the CODSASYL rules. I've looked at COBOL crash
> > > >> dumps on most of these systems and don't recall any of them using some
> > > >> form of non-native numeric storage, i.e. if you could read the assembler,
> > > >> the data division of the COBOL dump was understandable.
> > > > 
> > > > Intel 8080 had hardware support for BCD arithmetic
> > > > https://en.wikipedia.org/wiki/Half-carry_flag
> > > > 
> > > > While packed BCD does not make optimal use
> > > > of storage (about one-sixth of the memory used
> > > > is wasted), conversion to ASCII, EBCDIC, or
> > > > the various encodings of Unicode is still
> > > > trivial, as no arithmetic operations are
> > > > required. The extra storage requirements
> > > > are usually offset by the need for the
> > > > accuracy and compatibility with calculator
> > > > or hand calculation that fixed-point decimal
> > > > arithmetic provides. Denser packings of BCD
> > > > exist which avoid the storage penalty and
> > > > also need no arithmetic operations for
> > > > common conversions.
> > > > 
> > > > Packed BCD is supported in the COBOL programming
> > > > language as the "COMPUTATIONAL-3" (an IBM
> > > > extension adopted by many other compiler
> > > > vendors) or "PACKED-DECIMAL" (part of the
> > > > 1985 COBOL standard) data type. It is
> > > > supported in PL/I as "FIXED DECIMAL". Besides
> > > > the IBM System/360 and later compatible
> > > > mainframes, packed BCD is implemented
> > > > in the native instruction set of the
> > > > original VAX processors from Digital
> > > > Equipment Corporation and some models
> > > > of the SDS Sigma series mainframes, and
> > > > is the native format for the Burroughs
> > > > Corporation Medium Systems line of
> > > > mainframes (descended from the 1950s
> > > > Electrodata 200 series).
> > > 
> > > Note that there is a difference between supporting
> > > BCD format in memory and having the CPU support it.
> > > 
> > > Systems supporting BCD format in memory can process
> > > them in 3 different ways:
> > > 1) BCD instructions in the ISA implemented in actual
> > >     silicium
> > > 2) BCD instructions in the ISA implemented in
> > >     micro-code
> > > 3) non-BCD instructions
> > > 
> > > All will support COBOL COMP-3 fine.
> > > 
> > > #1 will be fastest, so if COBOL COMP-3 is a huge
> > > part of the actual workload for a given computer
> > > architecture then it makes sense.
> > > 
> > > Arne

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Thread

Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-01 10:20 -0700
  Re: Can Java compute 9^(9^9) ? Eric Sosman <esosman@comcast-dot-net.invalid> - 2018-06-01 13:36 -0400
    Re: Can Java compute 9^(9^9) ? j4n bur53 <janburse@fastmail.fm> - 2018-06-01 20:20 +0200
      Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-05 07:17 -0700
        Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-05 07:29 -0700
          Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-05 07:48 -0700
          Re: Can Java compute 9^(9^9) ? Eric Sosman <esosman@comcast-dot-net.invalid> - 2018-06-05 10:57 -0400
            Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-05 09:32 -0700
              Re: Can Java compute 9^(9^9) ? Eric Sosman <esosman@comcast-dot-net.invalid> - 2018-06-05 13:58 -0400
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-05 11:10 -0700
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-05 11:21 -0700
                Re: Can Java compute 9^(9^9) ? Andreas Leitgeb <avl@logic.at> - 2018-06-06 08:50 +0000
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-06 01:58 -0700
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-06 02:01 -0700
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-06 10:34 -0700
  Re: Can Java compute 9^(9^9) ? j4n bur53 <janburse@fastmail.fm> - 2018-06-09 21:06 +0200
    Re: Can Java compute 9^(9^9) ? v_borchert@despammed.com (Volker Borchert) - 2018-06-09 23:29 +0000
      Re: Can Java compute 9^(9^9) ? Martin Gregorie <martin@mydomain.invalid> - 2018-06-10 09:13 +0000
        Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-10 02:31 -0700
          Re: Can Java compute 9^(9^9) ? Arne Vajhøj <arne@vajhoej.dk> - 2018-06-10 18:28 -0400
            Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-10 15:48 -0700
              Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-10 15:52 -0700
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-10 15:58 -0700
              Re: Can Java compute 9^(9^9) ? Arne Vajhøj <arne@vajhoej.dk> - 2018-06-10 21:17 -0400
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-11 13:20 -0700
                Re: Can Java compute 9^(9^9) ? bursejan@gmail.com - 2018-06-14 13:37 -0700

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