Find a way to allow 5 bits for the shift and rotate amounts in the following instructions:
[x] xc.prot.i
[x] xc.psll.i
[x] xc.psrl.i
Could possibly be done by using the pack-width encoding ca||cb||cc = 1?1 and letting cb be the [M|L]SB of the new 5-bit shamt / ramnt field. Any pack width where ca=cc=1 then implies operations on the entire register word.
Pro: Fits without major encoding structure modifications
Con: Doesn't line up with RISC-V shamt field
Con: Makes decode of pack widths somewhat more fiddely, as this becomes a corner case for shift/rotate instructions.
Find a way to allow 5 bits for the shift and rotate amounts in the following instructions:
xc.prot.ixc.psll.ixc.psrl.iCould possibly be done by using the pack-width encoding
ca||cb||cc = 1?1and lettingcbbe the [M|L]SB of the new 5-bitshamt/ramntfield. Any pack width whereca=cc=1then implies operations on the entire register word.