GNURX toolchain generates incorrect opcode for "mov.b #0xff, [r0]" instruction.

[DJ Delorie]

> +	| MOV DOT_B '#' EXPR ',' '[' REG ']'
> +	 { B2 (0xf8, 0x04); IMMB ($4, 12);}

> However I am still facing issue with registers other than r0 like r1-r15. Can you please give 
> some hints how to go about with this.

In the other patterns you'll see something like this:

   F ($8, 9, 3);

where $8 is the REG.  That inserts the register's index into the opcode (in this
case, at bit position 9 size 3)