Representability check description doesn't capture address-wrapping edge cases

[PRugg-Cap]

The description of the representability check is slightly imprecise in cases where the base or top want to wrap the address space. A correction is described in the bounds section:

riscv-cheri/src/cap-description.adoc

Lines 501 to 502 in 8f58752

	if ( (E < (CAP_MAX_E - 1)) & (t[MXLEN: MXLEN - 1] - b[MXLEN - 1] > 1) )
	t[MXLEN] = !t[MXLEN]

but not in the representable region section, where it is also relevant:

riscv-cheri/src/cap-description.adoc

Lines 649 to 653 in 8f58752

	|==============================================================================
	| Configuration | Upper Section (if E + MW ≤ MXLEN) | Middle Section | Lower Section
	| EF=0 | address[MXLEN:E + MW] + ct | T[MW - 1:0] | {E{1'b0}}
	| EF=1, i.e. E=0 | address[MXLEN:MW] + ct 2+| T[MW - 1:0]
	|==============================================================================

In addition, we need to clarify what happens if the base wraps.

I'll need to think about how to describe this precisely, but just wanted to record the issue so it doesn't get missed. I don't think there's a bug, but somebody trying to implement it just from this description would certainly get confused!

[tariqkurd-repo]

PR for this one? @PRugg-Cap ?

[PRugg-Cap]

Not yet, sorry, I'll try tomorrow!