On Tuesday, 4 July 2017 at 00:35:10 UTC, H. S. Teoh wrote:
On Mon, Jul 03, 2017 at 07:13:45AM +0000, Era Scarecrow via
Digitalmars-d-learn wrote:
On Monday, 3 July 2017 at 06:20:22 UTC, H. S. Teoh wrote:
[...]
> I don't think there's a way to change how the FPU works --
> the hardware is coded that way and can't be changed. You'd
> have to build your own library or use an existing one for
> this purpose.
It's been a while, i do recall there was BCD options,
actually found
a few of the instructions; However they are more on
loading/storing
the value, not on working strictly in that mode. Last i
remember
seeing references to BCD work was in 2000 or so.
I'll have to look further before i find (or fail to find) all
that's
BCD related. Still if it IS avaliable, it would be an x87 only
option
and thus wouldn't be portable unless the language or a library
offered
support.
Wow, that brings back the memories... I used to dabble with BCD
(only a little bit) back when I was playing with 8086/8088
assembly language. But I've not heard anything about BCD since
that era, and I'm surprised people still know what it is. :-D
But all I knew about BCD was in the realm of integer
arithmetic. I had no idea such things as BCD floats existed.
In times of lore, BCD floats were very common. The Sharp Pocket
Computer used a BCD float format and writing machine code on them
confronts one with the format. The TI-99/4A home computer also
used a BCD float format in its Basic interpreter. It had the same
properties as the float format of the TI calculators, i.e. 10
visible significant digits (+ 3 hidden digits) and exponents
going from -99 to +99. It is only then when I switched to the
Apple II Applesoft Basic that I discovered the horrors of binary
floating point numbers.
Since the generalization of arithmetic co-processors does one
only see binary floats anymore.
