Question

I have a set of 6 bits that represent a 7bit ASCII character. How can I get the correct 7bit ASCII code out of the 6 bits I have? Just append a zero and do an bitwise OR?

Thanks for your help.

Lennart

Answer 1

ASCII is inherently a 7-bit character set, so what you have is not “6-bit ASCII”. What characters make up your character set? The simplest decoding approach is probably something like:

char From6Bit( char c6 ) {
    // array of all 64 characters that appear in your 6-bit set
    static SixBitSet[] = { 'A', 'B', ... }; 
    return SixBitSet[ c6 ];
}   

A footnote: 6-bit character sets were quite popular on old DEC hardware, some of which, like the DEC-10, had a 36-bit architecture where 6-bit characters made some sense.