[cctalk] Re: BCD (Was: What constitutes a dead computer language

[Paul Koning via cctalk]

> On Jun 23, 2026, at 11:28 PM, Ken Seefried via cctalk <cctalk@classiccmp.org> 
> wrote:
> 
> On Mon, Jun 22, 2026 at 4:33 PM Fred Cisin via cctalk <cctalk@classiccmp.org>
> wrote:
> 
>>> My question "what is that used for?"  Answer:
>>> "compound interest in COBOL programming".
>>> Oh yeah.
>> 
>> That's what it is for
>> 
>> 
> Unfortunately (or not?) the x86 BCD instructions have been removed from
> '64-bit mode' in x86-64.  I assume those processors are fast enough
> emulating BCD if required to keep COBOL users happy.
> 
> The PDP-11 CIS instructions include BCD types and are very
> interesting/weird (e.g. EDIT instruction).

I never looked at PDP-11 or VAX decimal instructions all that much, but from a 
superficial look they seemed to be inspired by the analogous instructions of 
the IBM 360 series, including (I'm pretty sure) the EDIT instruction.

        paul