and naming the inputs for MuxA A,B,C,D + MuxB E,F,G,H you can make a sort of mapping truth table to indicate which bits should pass through on the muxes:
2 1 0
0 0 0 A
0 0 1 B
0 1 0 C
0 1 1 D
1 0 0 E
1 0 1 F
1 1 0 G
1 1 1 H
So obviously pin A on muxA is akin to pin E on muxB.
So I think we can say by looking at first bit in the above it indicate 0 for MuxA or 1 for MuxB.
And bits 1 and 0 can then just be passed to whichever mux bit 2 indicates.
So I'm wondering how to do this, then I realised that's effectively what a Demuxer does, isn't it?
I'm thinking I could use a demuxer and set the sel bit to bit 2 from the above table where the demuxer output goes via outa to MuxA or outb to MuxB, but the problem I'm encountering is that I think I need a two bit Demuxer to do it?
So I'm wondering, given the lack of templates for this, am I barking up the wrong tree? I suspect I am, it just seemed the right thing to do to try to work two 4way muxes to build an 8way.]
Perhaps the right way is to just back up a bit and build the 8 way from individual 16bit muxes.