[Info-vax] Kednos PL/I

[gah4]

On Wednesday, September 13, 2023 at 5:53:20 PM UTC-7, Arne Vajhøj wrote:

(snip, I wrote)
> > It has been usual for a long time, for hardware to have multiply and divide with 
> > double length product and dividend. Many algorithms depend on that, though few 
> > HLLs have a way to do it. (Other than call an assembly language routine.) 
 
> > It seems that 64 bit processors don't all do it.

> Big integers in software is pretty standard today. You can get 
> 128 or 245 or 512 or 1024 bit integers or whatever if you want to. 
> In software. And on todays hardware it will be pretty fast anyway. 
 
I suppose so.
It is reasonable to expect HLLs to support what the hardware supports.

I remember in the TeX documentation for the program, TeX has (had)
Pascal programs to compute the product and quotient of 32 bit values
with 16 bits after the binary point.  Very easy if you have the double length
instructions, not at all easy in Pascal.

He suggests assembly versions of those two operations.

But computers were slower then. 

If you are using them to implement multiple precision arithmetic, you
want to use the largest ones supported by the hardware.  But yes,
often enough they are fast enough.