README.md

   1 # IEEE754 Floating-Point ALU, in nmigen
   2
   3 This project implements a pipelined IEEE754 floating-point ALU that
   4 supports FP16, FP32 and FP64.  It is a general-purpose unit that
   5 may be used in any project (not limited to one specific processor).
   6
   7 Developed under a Grant from NLnet (http://nlnet.nl), more information
   8 may be found at http://libre-soc.org
   9
  10 # Requirements
  11
  12 * nmigen
  13 * libresoc-nmutil
  14 * yosys (latest git repository, required by nmigen)
  15 * sfpy (running unit tests).  provides python bindings to berkeley softfloat-3
  16
  17 # Building sfpy
  18
  19 The standard sfpy will not work without being modified to the type of
  20 IEEE754 FP emulation being tested.  This FPU is emulating RISC-V, and
  21 there is some weirdness in x86 IEEE754 implementations when it comes
  22 to FP16 non-canonical NaNs.
  23
  24 The following modifications are required to the sfpy berkeley-softfloat-3
  25 submodule:
  26
  27     cd /path/to/sfpy/berkeley-softfloat-3
  28     git apply /path/to/ieee754fpu/berkeley-softfloat.patch
  29
  30 The following modifications are required to the sfpy SoftPosit Makefile:
  31
  32     cd /path/to/sfpy/SoftPosit
  33     git apply /path/to/ieee754fpu/SoftPosit.patch
  34
  35 # Useful resources
  36
  37 * https://en.wikipedia.org/wiki/IEEE_754-1985
  38 * http://weitz.de/ieee/
  39 * https://steve.hollasch.net/cgindex/coding/ieeefloat.html
  40