Binary-coded decimal arithmetic

Projects Programming
1

Anyone have a good set of functions for binary-coded decimal arithmetic?

One could increment a 2-digit BCD integer as follows:

x += ((x&15)==9?7:1); // does not check for overflow

or increase a 2-digit BCD integer by a given value as follows:

x += y;
if (((x&15)>9) || ((x&15)<(y&15))) x+=6;

but I want to know if there are faster or more efficient functions than these.

At this point, I am really only interested in 2-digit BCD numbers, though.

2

http://www.divms.uiowa.edu/~jones/bcd/bcd.html

3

Yes, but his algorithms seem a bit involved, at least for 2-digit BCD numbers.

The code I gave was just written off the top of my head.

4

Well, why do you want to do this? You could add them as "normal" numbers and then convert them.

5

Normally you do everything in binary and only convert to BCD if you have to display a number.

Why do you need to work with BCD?

Rob