[Info-vax] Kednos PL/I

[gah4]

On Wednesday, September 13, 2023 at 12:28:45 PM UTC-7, Arne Vajhøj wrote:

(snip, I wrote)

> > Does Alpha have 64 bit multiply and divide?

> In instruction set? 

> Multiply: yes. 

With 128 bit product?

> Division: no. But obviously you can divide two 64 bit integers in your 
> favorite HLL.

But PL/I allows for a scaling factor for FIXED BIN values.
That often requires a shift before the divide, so you really want a double
length dividend and product for divide and multiply instructions.

> > I even forget now, does x86-64 hardware have multiply and divide with 128 bit 
> > product and dividend?

> I don't think so. 

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.