Sujet : Re: Concertina IV Has Arrived
De : quadibloc (at) *nospam* ca.invalid (quadi)
Groupes : comp.archDate : 21. May 2026, 03:33:51
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <10ulque$ej88$2@dont-email.me>
References : 1 2 3
User-Agent : Pan/0.144 (Time is the enemy; 5790967 bitbucket.org/one47/pan.git)
On Wed, 20 May 2026 01:35:01 +0000, MitchAlsup wrote:
quadi <quadibloc@ca.invalid> posted:
So instead I decided to only support double precision, and use the
extra bits to allow additional ways to specify registers.
My 66000 started out that way and the compiler showed that this choice
sucks.
The good news is that this only concerns the 16-bit short instructions. A
compiler can choose to ignore them if it can't handle them.
Currently, the 16-bit instructions provide the following:
All the basic operate instructions for two integer types; they can only
operate on the first eight integer registers.
The basic floating operate instructions for one floating-point type; the
register specification is the one used with Concertina II's paired 15-bit
operate instructions; choose one of four banks of eight registers, and
both operands must be in that bank.
The idea is that it can be used for efficient pipelined code where four
sequences of instructions which are independent are interleaved.
Everything else is straightforwards; the 24-bit short instructions and all
the 32-bit and longer instructions that operate on registers allow the use
of all 32 registers in a bank.
Of course, though, the other restrictions are still present - seven
choices for an index register, seven choices for a base register (for each
of three displacement sizes, 20, 16, and 12 bits).
I think I have indeed achieved the goal which, when I started out, I
thought might prove to be an "impossible dream" - combining what a CISC
instruction set offers with what a RISC instruction set offers, and yet
doing so without making the instructions longer than they usually are in
those instruction types.
Except for register-to-register operate instructions being 24 bits instead
of 16 bits, this has been achieved - but for a very limited subset of the
possible register-to-register operate instructions, chosen by me as the
ones I think are the most useful and popular - and I realize the choice is
subjective and hence potentially controversial - the 16-bit instruction
length is retained!
I think it's an ISA that, in this respect, has achieved more than anyone
could have expected!
Now, of course, whether or not this is an achievement that anyone cares
about, that anyone wants, that anyone is interested in... well, I don't
know.
John Savard
| Date | Sujet | # | | Auteur |
| 19 May 26 |  Concertina IV Has Arrived | 340 | | quadi |
| 20 May 26 |  Re: Concertina IV Has Arrived | 339 | | quadi |
| 20 May 26 |    Re: Concertina IV Has Arrived | 1 | | quadi |
| 20 May 26 | Re: Concertina IV Has Arrived | 337 | | MitchAlsup |
| 20 May 26 | Re: Concertina IV Has Arrived | 181 | | quadi |
| 20 May 26 |  Re: Concertina IV Has Arrived | 1 | | quadi |
| 20 May 26 | Byte order and BCD (was: Concertina IV Has Arrived) | 23 | | Anton Ertl |
| 20 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 6 | | Thomas Koenig |
| 20 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 5 | | Anton Ertl |
| 20 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 4 | | Thomas Koenig |
| 20 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 3 | | Anton Ertl |
| 20 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 2 | | Thomas Koenig |
| 20 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 1 | | Anton Ertl |
| 20 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 7 | | quadi |
| 20 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 6 | | Anton Ertl |
| 20 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 2 | | quadi |
| 21 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 1 | | Anton Ertl |
| 20 May 26 | Re: Byte order and BCD | 3 | | Terje Mathisen |
| 21 May 26 | Re: Byte order and BCD | 2 | | Anton Ertl |
| 21 May 26 | Re: Byte order and BCD | 1 | | Anton Ertl |
| 20 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 7 | | John Levine |
| 20 May 26 | Re: Byte order and BCD | 1 | | Terje Mathisen |
| 20 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 5 | | quadi |
| 21 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 4 | | John Levine |
| 21 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 3 | | quadi |
| 21 May 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 1 | | Anton Ertl |
| 21 May 26 | Re: ancient virtual memory, Byte order and BCD (was: Concertina IV Has Arrived) | 1 | | John Levine |
| 3 Jun 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 2 | | quadi |
| 3 Jun 26 | Re: Byte order and BCD (was: Concertina IV Has Arrived) | 1 | | Anton Ertl |
| 20 May 26 | Re: Concertina IV Has Arrived | 155 | | Bernd Linsel |
| 20 May 26 | Re: BCD, was Concertina IV Has Arrived | 154 | | John Levine |
| 1 Jun 26 | Re: BCD, was Concertina IV Has Arrived | 15 | | quadi |
| 1 Jun 26 | Re: BCD, was Concertina IV Has Arrived | 13 | | John Levine |
| 1 Jun 26 | 2s-complement and byte order (was: BCD) | 9 | | Anton Ertl |
| 1 Jun 26 | Re: 2s-complement and byte order (was: BCD) | 6 | | Thomas Koenig |
| 1 Jun 26 | Re: 2s-complement and byte order (was: BCD) | 5 | | Anton Ertl |
| 1 Jun 26 | Re: 2s-complement and byte order (was: BCD) | 4 | | John Levine |
| 2 Jun 26 | Re: 2s-complement and byte order (was: BCD) | 3 | | MitchAlsup |
| 2 Jun 26 | Re: 2s-complement and byte order (was: BCD) | 2 | | John Levine |
| 2 Jun 26 | Re: 2s-complement and byte order (was: BCD) | 1 | | MitchAlsup |
| 1 Jun 26 | Re: 2s-complement and byte order (was: BCD) | 1 | | quadi |
| 1 Jun 26 | Re: 2s-complement and byte order (was: BCD) | 1 | | John Levine |
| 1 Jun 26 | Re: BCD, was Concertina IV Has Arrived | 3 | | quadi |
| 1 Jun 26 | Re: BCD, was Concertina IV Has Arrived | 2 | | John Levine |
| 1 Jun 26 | Re: BCD, was Concertina IV Has Arrived | 1 | | quadi |
| 1 Jun 26 | byte order (was: BCD) | 1 | | Anton Ertl |
| 2 Jun 26 | Re: BCD, was Concertina IV Has Arrived | 138 | | John Dallman |
| 2 Jun 26 | Re: BCD, was Concertina IV Has Arrived | 6 | | quadi |
| 2 Jun 26 | Re: BCD, was Concertina IV Has Arrived | 5 | | MitchAlsup |
| 2 Jun 26 | Re: BCD, was Concertina IV Has Arrived | 2 | | Thomas Koenig |
| 2 Jun 26 | Re: BCD, was Concertina IV Has Arrived | 1 | | quadi |
| 2 Jun 26 | Re: BCD, was Concertina IV Has Arrived | 2 | | Stephen Fuld |
| 2 Jun 26 | Re: BCD, was Concertina IV Has Arrived | 1 | | MitchAlsup |
| 2 Jun 26 | Re: BCD, was Concertina IV Has Arrived | 1 | | MitchAlsup |
| 2 Jun 26 | bit order and byte order (was: BCD) | 5 | | Anton Ertl |
| 3 Jun 26 | Re: bit order and byte order (was: BCD) | 2 | | quadi |
| 3 Jun 26 | Re: bit order and byte order (was: BCD) | 1 | | Anton Ertl |
| 4 Jun 26 | Re: bit order and byte order (was: BCD) | 2 | | George Neuner |
| 4 Jun 26 | Re: bit order and byte order (was: BCD) | 1 | | Anton Ertl |
| 2 Jun 26 | Re: endian history, was BCD, was Concertina | 125 | | John Levine |
| 3 Jun 26 | Re: endian history, was BCD, was Concertina | 124 | | quadi |
| 3 Jun 26 | Re: endian history, was BCD, was Concertina | 2 | | MitchAlsup |
| 3 Jun 26 | Re: endian history, was BCD, was Concertina | 1 | | quadi |
| 3 Jun 26 | Re: endian history, was BCD, was Concertina | 121 | | Thomas Koenig |
| 3 Jun 26 | Re: endian history, was BCD, was Concertina | 120 | | quadi |
| 3 Jun 26 | Re: endian history, was BCD, was Concertina | 2 | | John Levine |
| 4 Jun 26 | Re: endian history, was BCD, was Concertina | 1 | | Brian G. Lucas |
| 3 Jun 26 | Re: endian history, was BCD, was Concertina | 21 | | Thomas Koenig |
| 5 Sep 26 | Re: endian history, was BCD, was Concertina | 20 | | John Dallman |
| 6 Sep 26 | Re: endian history, was BCD, was Concertina | 19 | | Thomas Koenig |
| 6 Sep 26 | Re: endian history, was BCD, was Concertina | 14 | | David Brown |
| 6 Sep 26 | Re: endian history, was BCD, was Concertina | 13 | | Thomas Koenig |
| 6 Sep 26 | Re: endian history, was BCD, was Concertina | 12 | | David Brown |
| 6 Sep 26 | Re: endian history, was BCD, was Concertina | 11 | | Thomas Koenig |
| 6 Sep 26 | Re: endian history, was BCD, was Concertina | 9 | | David Brown |
| 7 Sep 26 | Re: endian history, was BCD, was Concertina | 8 | | MitchAlsup |
| 7 Sep 26 | Re: endian history, was BCD, was Concertina | 5 | | David Brown |
| 7 Sep 26 | Re: endian history, was BCD, was Concertina | 4 | | MitchAlsup |
| 7 Sep 26 | Re: endian history, was BCD, was Concertina | 3 | | David Brown |
| 7 Sep 26 | Re: endian history, was BCD, was Concertina | 2 | | MitchAlsup |
| 8 Sep 26 | Re: endian history, was BCD, was Concertina | 1 | | David Brown |
| 8 Sep 26 | Re: endian history, was BCD, was Concertina | 1 | | David Brown |
| 8 Sep 26 | Re: endian history, was BCD, was Concertina | 1 | | Thomas Koenig |
| 7 Sep 26 | Re: endian history, was BCD, was Concertina | 1 | | Lawrence D’Oliveiro |
| 6 Sep 26 | Re: endian history, was BCD, was Concertina | 1 | | John Dallman |
| 7 Sep 26 | Re: endian history, was BCD, was Concertina | 3 | | John Levine |
| 7 Sep 26 | Re: endian history, was BCD, was Concertina | 2 | | Thomas Koenig |
| 8 Sep 26 | Re: endian history, was BCD, was Concertina | 1 | | John Levine |
| 5 Sep 26 | Re: endian history | 96 | | Lawrence D’Oliveiro |
| 5 Sep 26 | Re: endian history | 95 | | John Savard |
| 5 Sep 26 | Re: endian history | 57 | | Terje Mathisen |
| 5 Sep 26 | Re: endian history | 56 | | Thomas Koenig |
| 5 Sep 26 | Re: endian history | 48 | | Terje Mathisen |
| 5 Sep 26 | Re: endian history | 47 | | MitchAlsup |
| 6 Sep 26 | Re: endian history | 37 | | John Savard |
| 6 Sep 26 | Re: endian history | 36 | | Lawrence D’Oliveiro |
| 6 Sep 26 | Re: endian history | 34 | | John Savard |
| 6 Sep 26 | Re: endian history | 10 | | Lawrence D’Oliveiro |
| 8 Sep 26 | Re: endian history | 9 | | John Savard |
| 8 Sep 26 | Re: endian history | 8 | | Lawrence D’Oliveiro |
| 8 Sep 26 | Re: endian history | 7 | | John Savard |
| 7 Sep 26 | Re: endian history | 23 | | MitchAlsup |
| 7 Sep 26 | Re: endian history | 1 | | Tim Rentsch |
| 6 Sep 26 | Re: endian history | 5 | | BGB |
| 7 Sep 26 | Re: endian history | 4 | | Terje Mathisen |
| 5 Sep 26 | Re: endian history | 7 | | Lawrence D’Oliveiro |
| 6 Sep 26 | Re: endian history | 37 | | Lawrence D’Oliveiro |
| 20 May 26 | Re: Concertina IV Has Arrived | 1 | | MitchAlsup |
| 20 May 26 | Re: Concertina IV Has Arrived | 123 | | quadi |
| 21 May 26 | Re: Concertina IV Has Arrived | 6 | | quadi |
| 25 May 26 | Re: Concertina IV Has Arrived | 26 | | quadi |
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