C needs BCD...

Thomas M. Breuel breuel at harvard.ARPA
Fri Nov 9 23:51:42 AEST 1984


I fail to see the need for bcd arithmetic even in business computing:
-- bcd numbers use more storage: an 18 digit number takes up 9 bytes,
   whereas the corresponding binary representation takes 8 bytes.
-- bcd arithmetic is slower than binary arithmetic: even with special
   bcd hardware, still more memory accesses are required to get all
   the data into the alu and to write out the result.
-- bcd arithmetic may be 'easier' to convert to ascii strings, but I doubt
   that unpacking a bcd number is significantly faster than converting
   a binary number to an ascii string. Even if it were, it would
   probably be balanced by (2).
If you really want to add a new data type to 'C' then 'veryLong' (i.e.
64bit integers) might be a lot more useful than 'bcd'.

						Thomas.
						(breuel at harvard)

PS: if you are into commercial computing, why don't you use COBOL?
After all, probably >95% of all business software is written in it...



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