updates/023_2020mar26_decoder_emulator_started.mdwn

   1 So many things happened since the last update they actually need to go
   2 in the main update, even in summary form.  One big thing: Raptor Engineering
   3 sponsored us with remote access to a TALOS II Workstation!
   4
   5 # Introduction
   6
   7 Here's the summary (if it can be called a summary):
   8
   9 * [An announcement](http://lists.libre-riscv.org/pipermail/libre-riscv-dev/2020-March/004995.html)
  10   that we got the funding (which is open to anyone - hint, hint) resulted in
  11   at least three people reaching out to join the team.  "We don't need
  12   permission to own our own hardware" got a *really* positive reaction.
  13 * New team member, Jock (hello Jock!) starts on the coriolis2 layout,
  14   after Jean-Paul from LIP6.fr helped to dramatically improve how coriolis2
  15   can be used.  This resulted in a
  16   [tutorial](https://libre-riscv.org/HDL_workflow/coriolis2/) and a
  17   [huge bug report discussion](http://bugs.libre-riscv.org/show_bug.cgi?id=178)
  18 * Work has started on the
  19   [POWER ISA decoder](http://bugs.libre-riscv.org/show_bug.cgi?id=186),
  20   verified through
  21   [calling GNU AS](https://git.libre-riscv.org/?p=soc.git;a=blob;f=src/soc/decoder/test/test_decoder_gas.py;h=9238d3878d964907c5569a3468d6895effb7dc02;hb=56d145e42ac75626423915af22d1493f1e7bb143) (yes, really!)
  22   and on a mini-simulator
  23   [calling QEMU](https://git.libre-riscv.org/?p=soc.git;a=blob;f=src/soc/simulator/qemu.py;h=9eb103bae227e00a2a1d2ec4f43d7e39e4f44960;hb=56d145e42ac75626423915af22d1493f1e7bb143)
  24   for verification.
  25 * Jacob's simple-soft-float library growing
  26   [Power FP compatibility](http://bugs.libre-riscv.org/show_bug.cgi?id=258)
  27   and python bindings.
  28 * A Conference call with OpenPOWER Foundation Director, Hugh, and Timothy
  29   Pearson from RaptorCS has been established every two weeks.
  30 * The OpenPOWER Foundation is also running some open
  31   ["Virtual Coffee"](https://openpowerfoundation.org/openpower-virtual-coffee-calls/)
  32   weekly round-table calls for anyone interested, generally, in OpenPOWER
  33   development.
  34 * Tim sponsors our team with access to a Monster Talos II system with a
  35   whopping 128 GB RAM.  htop lists a staggering 72 cores (18 real
  36   with 4-way hyperthreading).
  37 * [Epic MegaGrants](http://lists.libre-riscv.org/pipermail/libre-riscv-dev/2020-March/005262.html)
  38   reached out (hello!) to say they're still considering our
  39   request.
  40 * A marathon 3-hour session with [NLNet](http://nlnet.nl) resulted
  41   in the completion of the
  42   [Milestone tasks list(s)](http://bugs.libre-riscv.org/buglist.cgi?component=Milestones&list_id=567&resolution=---)
  43   and a
  44   [boat-load](http://lists.libre-riscv.org/pipermail/libre-riscv-dev/2020-March/thread.html)
  45   of bug reports to the list.
  46 * Immanuel Yehowshua is participating in the Georgia Tech
  47   [Create-X](https://create-x.gatech.edu/) Programme, and is establishing
  48   a Public Benefit Corporation in Atlanta, as an ethical vehicle for VC
  49   Funding.
  50 * A [Load/Store Buffer](http://bugs.libre-riscv.org/show_bug.cgi?id=216)
  51   design and
  52   [further discussion](http://bugs.libre-riscv.org/show_bug.cgi?id=257)
  53   including on
  54   [comp.arch](https://groups.google.com/forum/#!topic/comp.arch/cbGAlcCjiZE)
  55   inspired additional writeup
  56   on the
  57   [6600 scoreboard](https://libre-riscv.org/3d_gpu/architecture/6600scoreboard/)
  58   page.
  59 * [Public-Inbox](http://bugs.libre-riscv.org/show_bug.cgi?id=181) was
  60   installed successfully on the server, which is in the process of
  61   moving to a [new domain name](http://bugs.libre-riscv.org/show_bug.cgi?id=182)
  62   [Libre-SOC](http://libre-soc.org)
  63 * Build Servers have been set up with
  64   [automated testing](http://lists.libre-riscv.org/pipermail/libre-riscv-dev/2020-March/005364.html)
  65   being established
  66
  67 Well dang, as you can see, suddenly it just went ballistic.  There's
  68 almost certainly things left off the list.  For such a small team there's
  69 a heck of a lot going on.  We have an awful lot to do, in a short amount
  70 of time: the 180nm tape-out is in October 2020 - only 7 months away.
  71
  72 # NLNet Funding announcement
  73
  74 TODO
  75
  76 # Coriolis2 experimentation started
  77
  78 TODO
  79
  80 # POWER ISA decoder and Simulator
  81
  82 TODO
  83
  84 # simple-soft-float Library and POWER FP emulation
  85
  86 The
  87 [simple-soft-float](https://salsa.debian.org/Kazan-team/simple-soft-float)
  88 library is a floating-point library Jacob wrote with the intention
  89 of being a reference implementation of IEEE 754 for hardware testing
  90 purposes. It's specifically designed to be written to be easier to
  91 understand instead of having the code obscured in pursuit of speed:
  92
  93 * Being easier to understand helps prevent bugs where the code does not
  94   match the IEEE spec.
  95 * It uses the [algebraics](https://salsa.debian.org/Kazan-team/algebraics)
  96   library that Jacob wrote since that allows using numbers that behave
  97   like exact real numbers, making reasoning about the code simpler.
  98 * It is written in Rust rather than highly-macro-ified C, since that helps with
  99   readability since operations aren't obscured, as well as safety, since Rust
 100   proves at compile time that the code won't seg-fault unless you specifically
 101   opt-out of those guarantees by using `unsafe`.
 102
 103 It currently supports 16, 32, 64, 128-bit FP for RISC-V, along with
 104 having a `DynamicFloat` type which allows dynamically specifying all
 105 aspects of how a particular floating-point type behaves -- if one wanted,
 106 they could configure it as a 2048-bit floating-point type.
 107
 108 It also has Python bindings, thanks to the awesome
 109 [PyO3](https://pyo3.rs/) library for writing Python bindings in Rust.
 110
 111 We decided to write simple-soft-float instead
 112 of extending the industry-standard [Berkeley
 113 softfloat](http://www.jhauser.us/arithmetic/SoftFloat.html) library
 114 because of a range of issues, including not supporting Power FP, requiring
 115 recompilation to switch which ISA is being emulated, not supporting
 116 all the required operations, architectural issues such as depending on
 117 global variables, etc. We are still testing simple-soft-float against
 118 Berkeley softfloat where we can, however, since Berkeley softfloat is
 119 widely used and highly likely to be correct.
 120
 121 simple-soft-float is [gaining support for Power
 122 FP](http://bugs.libre-riscv.org/show_bug.cgi?id=258), which requires
 123 rewriting a lot of the status-flag handling code since Power supports a
 124 much larger set of floating-point status flags and exceptions than most
 125 other ISAs.
 126
 127 Thanks to RaptorCS for giving us remote access to a Power9 system,
 128 since that makes it much easier verifying that the test cases are correct.
 129
 130 API Docs for stable releases of both
 131 [simple-soft-float](https://docs.rs/simple-soft-float) and
 132 [algebraics](https://docs.rs/algebraics) are available on docs.rs.
 133
 134 One of the really important things about these libraries: they're not
 135 specifically coded exclusively for Libre-SOC: like softfloat-3 itself
 136 (and also like the [IEEE754 FPU](https://git.libre-riscv.org/?p=ieee754fpu.git))
 137 they're intended for *general-purpose* use by other projects.  These are
 138 exactly the kinds of side-benefits for the wider Libre community that
 139 sponsorship, from individuals, Foundations (such as NLNet) and Companies
 140 (such as Purism and Raptor Engineering) brings.
 141
 142 # OpenPOWER Conference calls
 143
 144 TODO
 145
 146 # OpenPower Virtual Coffee Meetings
 147
 148 TODO
 149
 150 # Sponsorship by RaptorCS with a TALOS II Workstation
 151
 152 TODO http://lists.libre-riscv.org/pipermail/libre-riscv-dev/2020-March/005291.html
 153
 154 # Epic Megagrants
 155
 156 TODO
 157
 158 # NLNet Milestone tasks
 159
 160 TODO
 161
 162 # Georgia Tech CREATE-X
 163
 164 TODO
 165
 166 # LOAD/STORE Buffer and 6600 design documentation
 167
 168 TODO
 169
 170 # Public-Inbox and Domain Migration
 171
 172 TODO
 173
 174 # Build Servers
 175
 176 TODO
 177
 178 # Conclusion
 179
 180 TODO
 181
 182