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

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On 6/10/2018 6:48 PM, bursejan@gmail.com wrote:
> 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?

>>> 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.
 >
> 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.

Yes - VAX xxxP is BCD.

Length is necessary as there is a need to support different
lengths.

I would think even a pure silicium solution would need
that.

Arne

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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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