This is the reason behind the profiles like RVA23 which include bitmanip, vector and a large number of other extensions. Real chips coming very soon will all be RVA23.
replyNeat. I can't wait to get my hands on a devboard.
replyThe earlierst I know of coming is the SpaceMit K3, which Sipeed will have dev boards for.
replyThe Milk-V Jupiter 2 (coming out in April) is RV23 too
replyNice board but very low on max RAM.
reply32-bit barrel shifters consume significant area and RISC-V was developed to support resource constrained low cost embedded hardware in a minimal ISA implementation.
replyThe 32-bit ARM architecture included a barrel shifter as part of its basic design, as in every instruction had a shift field.
replyIf a CPU built in 1985 with a grand total of 26 000 transistors could afford it, I am pretty sure that anything built in this century could afford it too.
26k is a lot of transistors for a MCU.
replyRefer to e.g. SERV/QERV.
IIUC this is a lot less true in the modern era. Even with 24nm transistors (the cheapest transistor last time I checked), modern microcontrollers have a fairly big transistor budget for the core (since 80+% of the transistors are going to sram anyway).
replyYou can save a lot of silicon by doing 8 or 16 bit shifters and then doing the rest at the code generation level. Not having any seems really anemic to me.
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