Re: My 66000 and High word facility

On Sun, 11 Aug 2024 0:46:09 +0000, Brett wrote:

MitchAlsup1 <mitchalsup@aol.com> wrote:

<snip>

>
High registers is mostly marketing vapor ware extension for you, see if
anyone cares and put them on a list for when a market for that extension
pops up.
>
The lack of CPU’s with 64 registers is what makes for a market, that 4%
that could benefit have no options to pick from. You would be happy to
have control of a market that big. Point customers at a compiler
configured
for 64 registers and say that with high registers and inline constants
that
is what they could expect for code generation.

I agree with the lead in, and disagree with where you took it.
Let up postulate that having 64 registers is a 10% win (overstating
the size of its win my 2.5×) but that 98% of subroutines don't need
64-registers. So, 98% gains nothing and 2% gains 10%
     0.98*1.0 + 0.02*1.1 = 1.002
or
0.2% gain.

>
If there is demand for high registers you will probably just spin a CPU
arch with more registers, but that will never happen if you never ask.

The thing is that one you go down the GBOoO route, your lack of
registers
"namable in ASM" ceases to become a performance degrader. With renaming
one can have R7 in use 40 times in a 100 instruction deep execution
window.

This
is the definition of vapor ware, a free market survey. You can even add
more registers as an incompatible extension, if fact you should.

I will leave stuff like this to you.