From: lkcl Date: Thu, 13 Jun 2019 06:00:31 +0000 (+0100) Subject: (no commit message) X-Git-Tag: convert-csv-opcode-to-binary~4647 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=2ffadece15e5ccfe3f643d65a904f79dd3ca8854;p=libreriscv.git --- diff --git a/isa_conflict_resolution/isamux_isans.mdwn b/isa_conflict_resolution/isamux_isans.mdwn index a3a764de7..7522c5eea 100644 --- a/isa_conflict_resolution/isamux_isans.mdwn +++ b/isa_conflict_resolution/isamux_isans.mdwn @@ -80,6 +80,11 @@ going to work. thus, the need for having a per-privilege per-permutation utvec/stvec/htvec. +In this way, Hypervisor Mode can be applied recursively, as the traps execute in the (present) native namespace and jump out to a common one, using the stack to solve the issue of both recursive exceptions as well as higher privileged exceptions. + +Supervisor Modes have the option to continue to remain in the namespace in which the userspace is presently running (as does M Mode). Whilst this results in a need for trap vector proliferation of identical source code compiled for specific namespaces, it has the advantage of reducing latency, which may be critically important for real time applications. + + # What happens if this scheme is not adopted? Why is it better than leaving things well alone? At the first sign of an emergency non-backwards compatible and unavoidable change to the *frozen* RISCV *official* Standards, the entire RISCV community is fragmented and divided into two: