[ih] Intel 4004 vs the IMP

[Clem Cole]

Lord I'm more typing challenged today than normal:
Well given these are the features of the 316


ᐧ

On Mon, Nov 15, 2021 at 10:24 AM Clem Cole <clemc at ccc.com> wrote:

>
>
> On Mon, Nov 15, 2021 at 9:19 AM Steve Crocker via Internet-history <
> internet-history at elists.isoc.org> wrote:
>
>> Might it be possible to pin down the crossover date?  That is, when did a
>> microprocessor appear that was of the same power as the Honeywell 316?
>>
>> Well gioce these are the features of the 216:
>
> The programmers' model of the H-316 consisted of the following registers:
>
>
>    - The 16-bit *A* register was the primary arithmetic and logic
>       accumulator.
>       - The 16-bit *B* register was used for double-length arithmetic
>       operations.
>       - The 16-bit *program counter* holds the address of the next
>       instruction.
>       - A *carry flag* indicated arithmetic overflow.
>       - A 16-bit *X index* register was also provided for modification of
>       the address of operands.
>
> The instruction set <https://en.wikipedia.org/wiki/Instruction_set> had
> 72 arithmetic, logic, I/O and flow-control instructions.
>
> What I don't remember is the clock frequency, but I think it was in the
> order of .5-1Mz.  It used core which teneded to be slower than
> semiconductor memory at the time.
>
> So, I suspect if you just match the ISA's, first commercial microprocessor
> to come close to that would have been the M6809 which was introduced in
> 1978, which had two 8-bit A/B accumulators which combined to single 16-bit
> accumulator but also has a 16-bit D accumulator.  It also had 2 16 bit
> index registers (X and Y).   It was usually combined with semiconductor
> memory and clocked at 2 Mhz.
>
> The M68000 would come out as an experimental (unnumberred) chip for a 10
> of us a few months later and would be released for GA, in early/mid '79 [I
> was one of the people with the X-series chip at Tektronix, so I really
> don't remember the final GA time).  Certainly it would been workable.
>
> The question is if an 8-bit processor with a 16-bit address space like the
> 8080/Z80 or 6800/6502 would have been good enough.  They all tended to use
> semiconductor memory, so the memory speed of the 316 is likely to have been
> able to be matched/exceeded.  But the question is open if the code when
> converted to 8-bit ops to perform what had been done in 16-bits would have
> been reasonable.
>
> My >>WAG<< is that since so many slick video games got built on the 1Mhz
> 6502, I think an IMP might have been possible but  would have taken some
> very slick and careful coding I suspect.
>
> ᐧ
>