Support creation of memory maps

[xobs]

Memory maps are very useful for giving an overview of a computer system. One system may have multiple maps (such as a multi-core system, an 8051-like system, or a system with multiple buses).

Memory maps are similar to reg objects turned on their side with non-uniform spacing. Other packages have abused reg-like constructs to give satisfactory memory maps (e.g. http://www.martin-demling.de/2011/06/memory-maps-in-latex-using-the-bytefield-package/).

It would be nice for Wavedrom to support generation of memory maps.

[drom]

It is an interesting idea. wavedrom uses bit-filed rendering from this package: https://github.com/drom/bitfield , where related issues have to be filed.

[drom]

duplicate of #24