Unsigned Integer to BCD conversion?

Question

I know you can use this table to convert decimal to BCD:

0 0000

1 0001

2 0010

3 0011

4 0100

5 0101

6 0110

7 0111

8 1000

9 1001

Is there a equation for this conversion or you have to just use the table? Im trying to write some code for this conversion but Im not sure how to do the math for it. Suggestions?

Answer 1

You know the Binary numeral system, don't you?

Especially have a look at this chapter.

EDIT: Also note KFro's comment that the lower nibble (= 4 bits) of the binary ASCII representation of numerals is in BCD. This makes conversions BCD <-> ASCII very easy as you just have to add/remove the leading 4 bits:

Number    ASCII Code
0         0011 0000
1         0011 0001
 ...
8         0011 1000
9         0011 1001