M=1 being an indication "return to Standard v3.0B Encoding Mode".
* The 16-bit nop (bit 0, N=1) is intended for circumstances where a
return to Standard v3.0B Encoding is required for one cycle
- but one cycle where alignment to a 32-bit boundary is needed
+ but one cycle where alignment to a 32-bit boundary is needed.
+ Examples of this would be to return to "strict" (non-C) mode
+ where the PC may not be on a non-word-aligned boundary.
* If for any reason multiple 16 bit nops are needed in succession
- the 10-bit variant can be used, because each one returns to
+ the M=1 variant can be used, because each one returns to
Standard v3.0B Encoding Mode, each time.
In essence the 2 nops are needed due to there being 2 different C forms: 10 and 16 bit.