[libre-riscv-dev] sv.setvl encoding
Luke Kenneth Casson Leighton
lkcl at lkcl.net
Fri Jun 28 04:54:06 BST 2019
On Thu, Jun 27, 2019 at 11:38 PM Jacob Lifshay <programmerjake at gmail.com> wrote:
> I added the encoding I had originally planned under the "original encoding"
ok so SV is never going beyond RV64 without a major redesign as VL
and MVL are compacted into 6 bits (RV128 has XLEN=1<<7).
so, the field named MAXVL, practically speaking, need only be 6 bits, not 11.
the MAXVL field fits across the rs2 field rather than the top
immediate bits (normally a funct5/6/7). which would complicate
brownfield encoding that wanted an rs2.
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