[libre-riscv-dev] uniform instruction format

Luke Kenneth Casson Leighton lkcl at lkcl.net
Sun Jun 23 18:43:31 BST 2019

Someone named EricP spotted something, suggested an idea that was basically
equivalent to uepc and a bit more.

This caused me to review the handling of STATE in user mode traps and I
realised we need STATE, ueSTATE, seSTATE and meSTATE.

These to be swapped around a bit on traps, including u mode ones.

It actually reduces the number of CSRs, as an M Mode S Mode VL and MVL and
SUBVL are no longer needed.


crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68

More information about the libre-riscv-dev mailing list