[fpc-pascal] floating point an FPC

Marco van de Voort marcov at stack.nl
Tue Mar 2 12:02:35 CET 2010


In our previous episode, Jerry said:
>  I'm not sure but maybe Hewlett-Packard calculators use BCD. (HP  
> calculators are known for their excellent numerical accuracy.

Yes, at least the Saturn based ones do IIRC. They have 64-bit (16 digit)
copro registers as you can see here:

http://en.wikipedia.org/wiki/HP_Saturn_%28microprocessor%29

What's not in the link, but from my aging memory is that they can combine
two registers to achieve higher precision.

There are more odd things in the HP system btw, the whole HP firmware is
nibble based, like the CPU, and when you call "bytes free", it might
sometimes return "xx.5" :-)



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