README.md

   1 # IEEE754 Floating-Point ALU, in nmigen(tm)
   2
   3 nmigen (and all aliases) are Trademarks of M-Labs.
   4 nmigen is a Registered Trademark of M-Labs
   5 https://uspto.report/TM/88980893
   6
   7 This project implements a parameteriseable pipelined IEEE754 floating-point
   8 ALU that supports FP16, FP32 and FP64.  Other FP sizes (FP80, BF16, FP128)
   9 are a matter of adding new parameters for mantissa and exponent.
  10 The IEEE754 FP Library is a general-purpose unit that may be used in
  11 any project (not limited to one specific processor).  Limited Formal
  12 Correctness Proofs are provided (so far for fpadd, fpsub) as well as
  13 hundreds of thousands of unit tests.
  14
  15 Developed under Grants from NLnet (http://nlnet.nl), from
  16 EU Grants 871528 and 957073.  more information may be found at
  17 http://libre-soc.org
  18
  19 # Requirements
  20
  21 * nmigen (https://gitlab.com/nmigen/nmigen)
  22 * libresoc-nmutil (https://git.libre-soc.org/?p=nmutil.git;a=summary)
  23 * yosys (latest git repository, required by nmigen)
  24 * sfpy (running unit tests).  provides python bindings to berkeley softfloat-3
  25
  26 # Building sfpy
  27
  28 The standard sfpy will not work without being modified to the type of
  29 IEEE754 FP emulation being tested.  This FPU is emulating RISC-V, and
  30 there is some weirdness in x86 IEEE754 implementations when it comes
  31 to FP16 non-canonical NaNs.
  32
  33 The following modifications are required to sfpy:
  34
  35     cd /path/to/sfpy
  36     git apply /path/to/ieee754fpu/sfpy.patch
  37
  38 The following modifications are required to the sfpy berkeley-softfloat-3
  39 submodule:
  40
  41     cd /path/to/sfpy/berkeley-softfloat-3
  42     git apply /path/to/ieee754fpu/berkeley-softfloat.patch
  43
  44 The following modifications are required to the sfpy SoftPosit Makefile:
  45
  46     cd /path/to/sfpy/SoftPosit
  47     git apply /path/to/ieee754fpu/SoftPosit.patch
  48
  49 # Useful resources
  50
  51 * https://en.wikipedia.org/wiki/IEEE_754-1985
  52 * http://weitz.de/ieee/
  53 * https://steve.hollasch.net/cgindex/coding/ieeefloat.html
  54