+++ /dev/null
-#=======================================================================
-# Makefile for generating LaTeX documents
-#-----------------------------------------------------------------------
-#
-# This is a simple makefile for generating LaTeX documents. It will
-# run bibtex, generate eps from xfig figures, and make pdfs. The
-# makefile supports builds in non-source directories: just make a
-# build directory, copy the makefile there, and change the srcdir
-# variable accordingly.
-#
-# Note that the makefile assumes that the default dvips/ps2pdfwr
-# commands "do the right thing" for fonts in pdfs. This is true on
-# Athena/Linux and Fedora Core but is not true for older redhat installs ...
-#
-# At a minimum you should just change the main variable to be
-# the basename of your toplevel tex file. If you use a bibliography
-# then you should set the bibfile variable to be the name of your
-# .bib file (assumed to be in the source directory).
-#
-
-srcdir = ../src
-
-docs_with_bib = power-spec
-docs_without_bib =
-
-srcs = $(wildcard $(srcdir)/*.tex)
-figs = $(wildcard $(srcdir)/figs/*)
-bibs = $(srcdir)/power-spec.bib
-
-#=======================================================================
-# You shouldn't need to change anything below this
-#=======================================================================
-
-PDFLATEX := TEXINPUTS=$(srcdir): pdflatex -interaction=nonstopmode -halt-on-error
-BIBTEX := BIBINPUTS=$(srcdir): bibtex
-
-default : pdf
-
-#------------------------------------------------------------
-# PDF
-
-pdfs_with_bib = $(addsuffix .pdf, $(docs_with_bib))
-pdfs_without_bib = $(addsuffix .pdf, $(docs_without_bib))
-pdfs = $(pdfs_with_bib) $(pdfs_without_bib)
-
-pdf : $(pdfs)
-.PHONY: pdf open
-
-open: $(pdfs)
- open $(pdfs)
-
-$(pdfs_with_bib): %.pdf: $(srcdir)/%.tex $(srcs) $(figs) $(bibs)
- $(PDFLATEX) $*
- $(BIBTEX) $*
- $(PDFLATEX) $*
- $(PDFLATEX) $*
-
-$(pdfs_without_bib): %.pdf: $(srcdir)/%.tex $(srcs) $(figs)
- $(PDFLATEX) $*
- $(PDFLATEX) $*
-
-junk += $(pdfs) *.aux *.log *.bbl *.blg *.toc *.out
-
-#------------------------------------------------------------
-# Other Targets
-
-clean :
- rm -rf $(junk) *~ \#*
+++ /dev/null
-%
-\chapter{Introduction}
-
-\section{Why has Libre-SOC chosen PowerPC ?}
-
-For a hybrid CPU-VPU-GPU, intended for mass-volume adoption in tablets,
-netbooks, chromebooks and industrial embedded (SBC) systems, our choice was
-between Nyuzi, MIAOW, RISC-V, PowerPC, MIPS and OpenRISC.
-
-Of all the options, the PowerPC architecture is more complete and far more
-mature. It also has a deeper adoption by Linux distributions.
-
-Following IBM's release of the Power Architecture instruction set to the Linux
-Foundation in August 2019 the barrier to using it is no more than that of using
-RISC-V. We are encouraged that the OpenPOWER Foundation is supportive of what
-we are doing and helping, e.g by putting us in touch with people who can help
-us.
-
-\subsection{Summary}
-
-\vspace{-0.1in}
-\begin{itemize}
-\parskip 0pt
-\itemsep 1pt
-
-\item
- We propose the standardisation of the way that the PowerPC Instruction Set
- Architecture (PPC ISA) is extended, enabling many different flavours within a
- well supported family to co-exist, long-term, without conflict, right across
- the board.
-
-\item
-
- This is about more than just our project. Our proposals will facilitate the
- use of PPC in novel or niche applications without breaking the PPC ISA into
- incompatible islands.
-
-\item
-
- PPC will gain a competitive market advantage by removing the need for
- separate VPU or GPU functions in RTL or ASICs thus enabling lower cost
- systems. Libre-SOC's project is to extend the PPC to integrate the GPU and
- VPU functionality directly as part of the PPC ISA (example: Broadcom
- VideoCore IV being based around extensions to an ARC core).
-
-\item
-
- Libre-SOC's extensions will be easily adopted, as the standard GNU/Linux
- distributions will very deliberately run unmodified on our ISA, including
- full compatibility with illegal instruction trap requirements.
-
-\end{itemize}
-
-
-\subsection{One CPU multiple ISAs}
-
-This is a quick overview of the way that we would like to add changes that we
-are proposing to the PowerPC instruction set (ISA). It is based on a Open
-Standardisation of the way that existing "mode switches", already found in the
-POWER instruction set, are added:
-
-\begin{itemize}
-\parskip 0pt
-\itemsep 1pt
-
-\item
-
- FPSCR's "NI" bit, setting non-IEEE754 FP mode
-
-\item
-
- MSR's "LE" bit (and associated HILE bit), setting little-endian mode
-
-\item
-
- MSR's "SF" bit, setting either 32-bit or 64-bit mode
-
-\item
-
- PCR's "compatibility" bits 60-62, V2.05 V2.06 V2.07 mode
-
-\end{itemize}
-
-[It is well-noted that unless each "mode switch" bit is set, any alternative
-(additional) instructions (and functionality) are completely inaccessible, and
-will result in "illegal instruction" traps being thrown. This is recognised as
-being critically important.]
-
-These bits effectively create multiple, incompatible run-time switchable ISAs
-within one CPU. They are selectable for the needs of the individual program (or
-OS) being run.
-
-All of these bits are set by an instruction, that, once set, radically changes
-the entire behaviour and characteristics of subsequent instructions.
-
-With these (and other) long-established precedents already in POWER, there is
-therefore essentially conceptually nothing new about what we propose: we simply
-seek that the process by which such "switching" is added is formalised and
-standardised, such that we (and others, including IBM itself) have a clear,
-well-defined standards-non-disruptive, atomic and non-intrusive path to extend
-the POWER ISA for use in markets that it presently cannot enter.
-
-We advocate that some of "mode-setting" (escape-sequencing) bits be binary
-encoded, some unary encoded, and that some space marked for "offical" use, some
-"experimental", some "custom" and some "reserved". The available space in a
-suitably-chosen SPR to be formalised, and recommend the OpenPOWER Foundation be
-given the IANA-like role in atomically allocating mode bits.
-
-The IANA-like atomic role ensures that new PCR mode bits are allocated
-world-wide unique. In combination with a mandatory illegal instruction
-exception to be thrown on any system not supporting any given mode, the
-opportunity exists for all systems to trap and emulate all other systems and
-thus retain some semblance of interoperability. (Contrast this with either
-allocating the same mode bit(s) to two (or more) designers, or not making
-illegal exceptions mandatory: binary interoperability becomes unachievable and
-the result is irrevocable damage to POWER's reputation.)
-
-We also advocate to consider reserving some bits as a "countdown" where the new
-mode will be enabled only for a certain number of instructions. This avoids an
-explicit need to "flip back", reducing binary code size. Note that it is not a
-good idea to let the counter cross a branch or other change in PC (and to throw
-illegal instruction trap if attempted). However traps and exceptions themselves
-will need to save (and restore) the countdown, just as the rest of the PCR and
-other modeswitching bits need to be saved.
-
-Instructions that we need to add, which are a normal part of GPUs, include
-ATAN2, LOG, NORMALISE, YUV2RGB, Khronos Compliance FP mode (different from both
-IEEE754 and "NI" mode), and many more. Many of these may turn out to be useful
-in a wider context: they however need to be fully isolated behind
-"mode-setting" before being in any way considered for Standards-track formal
-adoption.
-
-Some mode-setting instructions are privileged, i.e can only be set by the
-kernel (e.g 32 or 64 bit mode). Most of the escape sequences that we propose
-will be (have to be) usable without the need for an expensive system call
-overhead (because some of the instructions needed will be in extremely tight
-inner loops).
-
-\subsection{About Libre-SOC Commercial Project}
-
-The Libre-SOC Commercial Product is a hybrid GPU-GPU-VPU intended for
-mass-volume production. There is no separate GPU, because the CPU is the GPU.
-There is no separate VPU, because the CPU is the GPU. There is not even a
-separate pipeline: the CPU pipelines are the GPU and VPU pipelines.
-
-Closest equivalents include the ARC core (which has VPU extensions and 3D
-extensions in the form of Broadcom's VideoCore IV) and the ICubeCorp IC3128.
-Both are considered "hybrid" CPU-GPU-VPU processors.
-
-"Normal" Commercial GPUs are entirely separate processors. The development cost
-and complexity purely in terms of Software Drivers alone is immense. We reject
-that approach (and as a small team we do not have the resources anyway).
-
-With the project being Libre - not proprietary and secretive and never to be
-published, ever - it is no good having the extensions as "custom" because
-"custom" is specifically for the cases where the augmented toolchain is never,
-under any circumstances, published and made public by the proprietary company
-(and would never be accepted upstream anyway). For business commercial reasons,
-Libre-SOC is the total opposite of this proprietary, secretive approach.
-
-Therefore, to meet our business objectives:
-
-\begin{itemize}
-\parskip 0pt
-\itemsep 1pt
-
-\item
-
- As shown from Nyuzi and Larrabee, although ideally suited to high
- performance compute tasks, a "traditional" general-purpose full
- IEEE754-compliant Vector ISA (such as that in POWER9) is not an adequate
- basis for a commercially competitive GPU. Nyuzi's conclusion is that using
- such general-purpose Vector ISAs results in reaching only 25% performance
- (or requiring 4-fold increase in power consumption) to achieve par with
- current commercial-grade GPUs.
-
-\item
-
- We are not going the "traditional" (separate custom GPU) route because it
- is not practical for a new team to design hardware and spend 8+ man-years
- on massively complex inter-processor driver development as well
-
-\item
-
- We cannot meet our objectives with a "custom extension" because the
- financial burden on our team to maintain a total hard fork of not just
- toolchains, but also entire GNU/Linux Distros, is highly undesirable, and
- completely impractical (we know for certain that Redhat would strongly
- object to any efforts to hard-fork Fedora)
-
-\item
-
- We could invent our own custom GPU instruction set (or use and extend an
- existing one, to save a man-decade on toolchain development) however even
- to switch over to that "Dual ISA" GPU instruction set in the next clock
- cycle still requires a PCR modeswitch bit in order to avoid needing a full
- Inter-Processor Bus Architecture like on "traditional" GPUs.
-
-\item
-
- If extending any instruction set, rather than have a Dual ISA (which needs
- the PCR modeswitch bit to access it) we would rather extend POWER.
-
-\item
-
- We cannot "go ahead anyway" because to do so would be highly irresponsible
- and cause massive disruption to the POWER community.
-
-\end{itemize}
-
-With all impractical options eliminated the only remaining responsible option
-is to extend the POWER ISA in an atomically-managed (IANA-style) formal
-fashion, whilst (critically and absolutely essentially) always providing a PCR
-compatibility mode that is fully POWER compliant, including all illegal
-instruction traps.
-
-
+++ /dev/null
-@Misc{foo-bar,
- title = "A dummy bib entry to keep LaTeX happy",
- publisher = {"Libre-SOC"},
- year = 2020
-}
-
+++ /dev/null
-%
-%=======================================================================
-% power-spec.tex
-%-----------------------------------------------------------------------
-
-\documentclass[twoside,11pt]{book}
-
-% Fix copy/pasting of ligatures in Acrobat
-\input{glyphtounicode.tex}
-\pdfgentounicode=1 %
-
-\input{preamble}
-
-\newcommand{\specrev}{\mbox{20200813-{\em draft}}}
-\newcommand{\specmonthyear}{\mbox{August 2020}}
-
-\begin{document}
-
-\title{\vspace{-0.7in}\Large {\bf Additions to The PowerPC Instruction Set Manual} \\
- \large {\bf Libre-SOC Extensions} \\
- Document Version \specrev
- \vspace{-0.1in}}
-
-\author{Editor: Alain D D Williams$^{1}$ \\
- $^{1}$Parliament Hill Computers Ltd, \\
- {\tt addw@phcomp.co.uk} \\
- \today
-}
-\date{}
-\maketitle
-
-Contributors to all versions of the spec in
-alphabetical order (please contact editors to suggest
-corrections):
-Luke Kenneth Casson Leighton, Jacob R Lifshay, Alain D D Williams
-
-This document is released under a Creative Commons Attribution 4.0
-International License.
-
-Please cite as: ``The PowerPC Instruction Set Additions, Document Version \specrev'', Editors
-Alain Williams, Libre-SOC, \specmonthyear.
-
-
-\markboth{Volume I: PowerPC ISAMUX \specrev}
-{Volume I: PowerPC ISAMUX \specrev}
-\thispagestyle{empty}
-
-\frontmatter
-
-\input{preface}
-
-{\hypersetup{linktoc=all,hidelinks}
-\tableofcontents
-}
-
-\mainmatter
-
-\input{intro}
-% \input{rv32}
-% \input{zifencei}
-% \input{rv32e}
-% \input{rv64}
-% \input{rv128}
-% \input{m}
-% \input{a}
-% \input{csr}
-% \input{counters}
-% \input{f}
-% \input{d}
-% \input{q}
-% \input{rvwmo}
-% \input{l}
-% \input{c}
-% \input{b}
-% \input{j}
-% \input{t}
-% \input{p}
-% \input{v}
-% \input{zam}
-% \input{ztso}
-% \input{gmaps}
-% \input{assembly}
-% \input{extensions}
-% \input{naming}
-% \input{history}
-%
-% \appendix
-% \input{memory}
-
-\bibliographystyle{plain}
-\bibliography{power-spec}
-
-\end{document}
+++ /dev/null
-% Package includes
-
-\usepackage{graphicx}
-\usepackage{geometry}
-\usepackage{array}
-\usepackage{colortbl}
-\usepackage[svgnames]{xcolor}
-
-\usepackage[colorlinks,citecolor=Navy,linkcolor=Navy]{hyperref}
-\usepackage{placeins}
-\usepackage{longtable}
-\usepackage{multirow}
-\usepackage{float}
-\usepackage{listings}
-\usepackage{comment}
-\usepackage{enumitem}
-\usepackage{verbatimbox}
-\usepackage{amsmath}
-
-\usepackage[olditem,oldenum]{paralist}
-
-% Setup margins
-
-\setlength{\topmargin}{-0.5in}
-\setlength{\textheight}{9in}
-\setlength{\oddsidemargin}{0in}
-\setlength{\evensidemargin}{0in}
-\setlength{\textwidth}{6.5in}
-
-% Useful macros
-
-\newcommand{\note}[1]{{\bf [ NOTE: #1 ]}}
-\newcommand{\fixme}[1]{{\bf [ FIXME: #1 ]}}
-\newcommand{\todo}[1]{\marginpar{\footnotesize #1}}
-
-\newcommand{\wunits}[2]{\mbox{#1\,#2}}
-\newcommand{\um}{\mbox{$\mu$m}}
-\newcommand{\xum}[1]{\wunits{#1}{\um}}
-\newcommand{\by}[2]{\mbox{#1$\times$#2}}
-\newcommand{\byby}[3]{\mbox{#1$\times$#2$\times$#3}}
-
-\newlength\savedwidth
-\newcommand\whline[1]{%
- \noalign{%
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- }%
- \cline{#1}%
- \noalign{\vskip\arrayrulewidth}%
- \noalign{\global\arrayrulewidth\savedwidth}%
-}
-
-% Custom list environments
-
-\newlist{tightlist}{itemize}{1}
-\setlist[tightlist]{label=\textbullet,nosep}
-
-\newenvironment{titledtightlist}[1]
-{\noindent
- ~~\textbf{#1}
- \begin{tightlist}}
-{\end{tightlist}}
-
-\newenvironment{commentary}
-{ \vspace{-1.5mm}
- \list{}{
- \topsep 0mm
- \partopsep 0mm
- \listparindent 1.5em
- \itemindent \listparindent
- \rightmargin \leftmargin
- \parsep 0mm
- }
- \item
- \small\em
- \noindent\nopagebreak\rule{\linewidth}{1pt}\par
- \noindent\ignorespaces
-}
-{\endlist}
-
-%\newenvironment{discussion}
-%{ \vspace{-1.5mm}
-% \list{}{
-% \topsep 0mm
-% \partopsep 0mm
-% \listparindent 1.5em
-% \itemindent \listparindent
-% \rightmargin \leftmargin
-% \parsep 0mm
-% }
-% \item
-% \small\em
-% \noindent\nopagebreak\rule{\linewidth}{1pt}\par
-% \noindent\textbf{Discussion:}
-%}
-%{\endlist}
-
-% Other commands and parameters
-
-\pagestyle{myheadings}
-\setlength{\parindent}{0in}
-\setlength{\parskip}{10pt}
-\sloppy
-\raggedbottom
-\clubpenalty=10000
-\widowpenalty=10000
-
-% Commands for register format figures.
-
-% New column types to use in tabular environment for instruction formats.
-% Allocate 0.18in per bit.
-\newcolumntype{I}{>{\centering\arraybackslash}p{0.18in}}
-% Two-bit centered column.
-\newcolumntype{W}{>{\centering\arraybackslash}p{0.36in}}
-% Three-bit centered column.
-\newcolumntype{F}{>{\centering\arraybackslash}p{0.54in}}
-% Four-bit centered column.
-\newcolumntype{Y}{>{\centering\arraybackslash}p{0.72in}}
-% Five-bit centered column.
-\newcolumntype{R}{>{\centering\arraybackslash}p{0.9in}}
-% Six-bit centered column.
-\newcolumntype{S}{>{\centering\arraybackslash}p{1.08in}}
-% Seven-bit centered column.
-\newcolumntype{O}{>{\centering\arraybackslash}p{1.26in}}
-% Eight-bit centered column.
-\newcolumntype{E}{>{\centering\arraybackslash}p{1.44in}}
-% Ten-bit centered column.
-\newcolumntype{T}{>{\centering\arraybackslash}p{1.8in}}
-% Twelve-bit centered column.
-\newcolumntype{M}{>{\centering\arraybackslash}p{2.2in}}
-% Sixteen-bit centered column.
-\newcolumntype{K}{>{\centering\arraybackslash}p{2.88in}}
-% Twenty-bit centered column.
-\newcolumntype{U}{>{\centering\arraybackslash}p{3.6in}}
-% Twenty-bit centered column.
-\newcolumntype{L}{>{\centering\arraybackslash}p{3.6in}}
-% Twenty-five-bit centered column.
-\newcolumntype{J}{>{\centering\arraybackslash}p{4.5in}}
-
-\newcommand{\instbit}[1]{\mbox{\scriptsize #1}}
-\newcommand{\instbitrange}[2]{~\instbit{#1} \hfill \instbit{#2}~}
-\newcommand{\reglabel}[1]{\hfill {\tt #1}\hfill\ }
-
-\newcommand{\wiri}{\textbf{WIRI}}
-\newcommand{\wpri}{\textbf{WPRI}}
-\newcommand{\wlrl}{\textbf{WLRL}}
-\newcommand{\warl}{\textbf{WARL}}
-
-\newcommand{\unspecified}{\textsc{unspecified}}
+++ /dev/null
-\chapter{Preface}
-
-This document describes the Libre-SOC ISAMUX additions to the PowerPC architecture.
-
-\cite{foo-bar}
--- /dev/null
+% C++ Atomics
+% https://bugs.libre-soc.org/show_bug.cgi?id=236
--- /dev/null
+% Write-up of the augmentation of POWER ISA to switch on IEEE754 FP16
+% https://bugs.libre-soc.org/show_bug.cgi?id=239
}
}
+\newglossaryentry{ICubeCorpIC3128}
+{
+ name=ICubeCorp IC3128,
+ description={
+ A \gls{SoC} from ICube that has both \gls{CPU} and \gls{GPU} on a single chip.
+ See: \href{https://www.cnx-software.com/2014/10/15/icube-mvp-socs-combine-cpu-and-gpu-into-a-single-unified-processing-unit-upu/}{CNX Software}
+ }
+}
+
\newglossaryentry{IEEE754}
{
name=IEEE754,
}
}
+\newglossaryentry{IOMMU}
+{
+ name=IOMMU,
+ description={
+ Input Output Memory Management Unit.
+ Mediates between Input/Output devices and main memory mapping virtual
+ addresses to physical ones and, maybe, enforcing protection restrictions.
+ See: \href{https://en.wikipedia.org/wiki/Input%E2%80%93output_memory_management_unit}{Wikipedia}
+ }
+}
+
\newglossaryentry{ISA}
{
name=ISA,
}
}
+\newglossaryentry{ISAMUX}
+{
+ name=ISAMUX,
+ description={
+ \gls{ISA} \gls{MUX} -- having the same bits in the ISA mean different things.
+ }
+}
+
+\newglossaryentry{H.265}
+{
+ name=H.265,
+ description={
+ High Efficiency Video Coding, also known as HEVC \& MPEG-H Part 2.
+ Released in 2013.
+ Its data compression is better, for the same video quality, than previous standards:
+ AVC, H.264, or MPEG-4 Part 10.
+ Patent license may be required for H.265 use.
+ See: \gls{VP9}
+ \href{https://en.wikipedia.org/wiki/High_Efficiency_Video_Coding}{Wikipedia}
+ }
+}
+
\newglossaryentry{JIT}
{
name=JIT,
}
}
+\newglossaryentry{MISA}
+{
+ name=MISA,
+ description={
+ Multiple Instruction Sets Architecture.
+ The ability to run more than one \gls{ISA} on the same hardware.
+ A setting in a \gls{CSR} controls which instructions will be
+ recognised at any time.
+ See: \href{}{}
+ }
+}
+% https://ieeexplore.ieee.org/document/6136696 - paywalled
+% https://www.researchgate.net/figure/Overview-of-the-MISA-instructional-system-design-method_fig2_245165034
+% https://people.eecs.berkeley.edu/~krste/papers/riscv-privileged-v1.9.pdf page 15
+
+\newglossaryentry{MUX}
+{
+ name=MUX,
+ description={
+ Multiplex, a way of compressing several things into the same data.
+% See: \href{}{}
+ }
+}
\newglossaryentry{PowerPC}
{
}
}
+\newglossaryentry{VideoCoreIV}
+{
+ name=VideoCore IV,
+ description={
+ Low power \gls{SoC} from Broadcom. ARM CPU that is used in the Raspberry Pi.
+ See: \href{https://en.wikipedia.org/wiki/VideoCore}{Wikipedia}
+ }
+}
+
+\newglossaryentry{VP9}
+{
+ name=VP9,
+ description={
+ Video encoding format released by Google in 2013.
+ Released open \& royalty free although Sisvel has made some claims.
+ See: \href{https://en.wikipedia.org/wiki/VP9}{Wikipedia}
+ }
+}
+
+% https://libre-soc.org/vpu/
\newglossaryentry{VPU}
{
name=VPU,
description={
- Video Processing Unit and Visual Processing Unit and Vector Processing Unit
- Contrast with \gls{CPU} and \gls{GPU}.
+ Video Processing Unit.
+ Similar to a \gls{CPU} but has extra hardware instructions to speed up things
+ like the decoding and encoding of \gls{H.265}, or \gls{VP9}.
% See: \href{}{}
}
}
% namespace
% MSB
% PCR
+% SIMD
+% ALU
+% RA
+% RB
+% microwatt https://github.com/antonblanchard/microwatt/blob/master/decode1.vhdl
+% 6600 https://libre-soc.org/3d_gpu/architecture/6600scoreboard/
+% DAG Directed Acyclic Graph
+% SR latch
+% FU Functional Unit
+% FPU float point unit
+% WAR https://libre-soc.org/3d_gpu/architecture/6600scoreboard/ #10
+% ALU
+% FU-FU function to function https://libre-soc.org/3d_gpu/architecture/6600scoreboard/ #14
+% GORD GOWR GO read/write
% ISANS
+% Unified Processing Unit (UPU)
+% MVP (Multi-thread Virtual Pipeline
% SIE
-% MISA
% WARL
% WLRL
separate pipeline: the CPU pipelines are the GPU and VPU pipelines.
Closest equivalents include the ARC core (which has VPU extensions and 3D
-extensions in the form of Broadcom's VideoCore IV) and the ICubeCorp IC3128.
+extensions in the form of Broadcom's \gls{VideoCoreIV}) and the \gls{ICubeCorpIC3128}.
Both are considered \textbf{hybrid} CPU-GPU-VPU processors.
\textbf{Normal} Commercial GPUs are entirely separate processors. The development cost
--- /dev/null
+% Write-up of a suitable compressed ISA Opcode protocol
+% https://bugs.libre-soc.org/show_bug.cgi?id=238
% ISAMUX
+% https://bugs.libre-soc.org/show_bug.cgi?id=214
\chapter{Introduction}
}
\end{verbatim}
-\subsection{Is this like MISA?} \label{misa}
+\subsection{Is this like \gls{MISA} ?} \label{misa}
\paragraph{}
\item
-MISA switches on and off entire extensions: ISAMUX/NS may be used to switch
+MISA switches on and off entire extensions: \gls{ISAMUX}/NS may be used to switch
multiple opcodes (present and future), to alternate meanings.
\item
\input{intro}
\input{isamux}
+\input{atomics}
+\input{varenc}
+\input{isa_op_protocol}
+% https://bugs.libre-soc.org/show_bug.cgi?id=238
+\input{fp16}
% \input{rv32}
% \input{zifencei}
--- /dev/null
+% Write-up of the Variable-sized Opcode protocol
+% https://bugs.libre-soc.org/show_bug.cgi?id=174