Bite operations with ShL and ShR

[ahenry3068]

Its good code.    And I've been playing with similar techniques to pack RAM more tightly on the X16 a neo-retro 8 bit computer.    However,  I can't see why would ever need this technique on even a barely modern system.    It's seems kind of a waste for a relatively small RAM savings.     

   No offense meant.   It is quite nice code actually.    IMO I just don't see the point.   .

The point is to use a variable for bit-packing.   In this case though, I personally think I'd just use a custom type and save myself a lot of shifting and headache.

TYPE msl_type
    game as _byte
    mask as _byte
    hour as _byte
    minute as _byte
    second as _byte
END TYPE

5 bytes with each to use, access, and something everyone can understand at a glance.   Compared to 4 bytes which is rather complex for a lot of folks to ever sort out and work with.

Trust me, I can promise you which one is easiest to come back to and work on after a 2 year break or whatnot.

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Its good code.    And I've been playing with similar techniques to pack RAM more tightly on the X16 a neo-retro 8 bit computer.    However,  I can't see why would ever need this technique on even a barely modern system.    It's seems kind of a waste for a relatively small RAM savings.     

   No offense meant.   It is quite nice code actually.    IMO I just don't see the point.   .

What's the point? Huge. Just read the documentation for MP3 or MP4 format, for GIF format, also for TTF font files, for 1-bit bitmaps and so on. Bit fields need to be decoded everywhere, it's a perfectly common practice.

It's also not just for modern formats.  Even old-school graphics did this with bit packing for black/white screens.   Screen 7(I think) packs it's memory into 4-bit nibbles (half-bytes).   It's not rare at all to see this type of thing in use with more advanced code and projects. 

  Ahh.  Ok I stand corrected.   I just didn't get the context for the code.      I didn't think of decoding packed file formats at all.   I've been using bit packed variables to save memory and that's what I thought of first...     I'll think twice next time.