Reason for using BCD arithmetic

[Hume Smith]

In article <8737 at smoke.BRL.MIL> gwyn at brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>) writes:
>In article <8810211335.AA19348 at ucbvax.Berkeley.EDU> BBUXEIPD at UIAMVS.BITNET (Robert Pearson) writes:
>>You are quite correct that BCD arithmetic has 'roundoff error'.
>>That is incorrect.  Not all so-called "floating point" schemes have fixed
>>significand size, and some (including those using variable-length BCD
>>strings) are able to represent results of arithmetic operations exactly.

I was about to say: Even sqrt(2)? arctan(1)? exp(1)?  but then I realised
these aren't EXACTLY arithmetic operations.  Can someone clarify?

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